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Climate Change Is About to Make Foodborne Illnesses More Powerful, Researchers Warn

Climate Change Is About to Make Foodborne Illnesses More Powerful, Researchers Warn

The pre-harvest stage of food production poses the greatest risk of contamination by pathogens like Salmonella and E. coli. (Photo Modified: Flickr/m.shattock)

Climate change, which is causing rising temperatures all over the world, is expected to compromise global food security and increase the rate of foodborne illness, according to a new study published in Food Research International.

The study, a collaboration between Ghent University in Belgium and Wageningen University in the Netherlands, was conducted for the Veg-i-Trade, a European research project which specifically explores the link between climate change and foodborne illness.

“Climate change is expected to challenge the effectiveness of food safety management systems in the near future,” the study cautions. “Climate and weather events play an important role in the presence of pathogens as warmer ambient temperature in combination with differences in eating behavior may contribute to the foodborne portion of the increased incident of enteric (intestinal) diseases.”

Areas of particular concern include the facilitation of easier contact between food and contaminants, growth of mold, and blooms of algae that may be increasingly harmful to shellfish. What’s more, researchers predicted that the use of pesticides would increase, as existing pests are expected to adapt to environmental changes.

Climate Change Is About to Make Foodborne Illnesses More Powerful, Researchers Warn - Recipes

Researchers warn that poor diet quality is now the number one risk factor killing more people than several other diseases combined. Even the ones who have enough to eat are not eating the right types of diverse foods, in optimal amount or time. The Global Nutrition Report 2018 documents that while more than four in 10 children drink sugary drinks daily, one in three does not eat fruits every day. There&rsquos not one income group that&rsquos eating enough healthy foods, like vegetables, whole grains or legumes. While 821 million people sleep hungry each day, two billion of us are overweight-obese on this planet. This poses a double whammy to public health, because low birth-weight or stunted children are more vulnerable to obesity and non-communicable diseases&mdash diabetes, heart problems, hypertension and more. The food environment doesn&rsquot help either if they live in a country where the market for unhealthy, processed foods is expanding rapidly. Recently published analysis of over 23,000 packaged food products found the vast majority (69 per cent) were of relatively poor nutrient quality (high in added sugar, sodium and unhealthy fats) especially in two most populous countries India and China. Diet diversity is plummeting and the frequency of eating out is increasing multi-fold&mdashreveal national surveys and research studies.

The past decade has been illuminating and exciting for nutrition advocates like me. A lot of attention is being rightfully given to eradication of malnutrition in all its forms. In fact, sustainable, resilient food systems for healthy diets have been identified as the first of the six pillars for action during the UN Decade of Action on Nutrition (2015-2025). A sustainable food system is defined as the one &ldquothat ensures food security and nutrition for all in such a way that the economic, social and environmental bases to generate food security and nutrition of future generations are not compromised&rdquo. A sustainable global food system by 2050 means sufficiently healthy food for all, with no additional land use conversion for food, protection of biodiversity, reduced water use, decreased nitrogen and phosphorus loss to waterways, net zero carbon dioxide emissions, and significantly lower levels of methane and nitrous oxide emissions.

Climate change is being recognised as a more active adversary for nutrition than previously contemplated. Every one degree rise in temperature results in about 10 per cent loss in production of staples. This small rise also translates to big nutrient losses in the form of dilution of water soluble vitamins and minerals, especially in fruits and vegetables. Additionally, climate change results in more floods, famines and other adverse situations which make disadvantaged people even more food insecure. Climate change can have an impact on environmental health issues, such as sanitation, water availability, access and quality and the transmission of waterborne, food-borne, vector-borne, and other diseases. Such diseases, in turn, reduce the body&rsquos absorption and utilisation of essential nutrients, effectively increasing overall nutritional needs. The linkages between agriculture, public health, environment and nutrition are being discussed but the pace and quantum of discussion urgently need to be accelerated across all possible platforms.

Thus during this Poshan Maah celebration in India, we present five key strategies which may guide action to tackle multiple forms of malnutrition from a multi-sectoral (especially, environment) lens.


Generate and/or collate (as required) evidence and action plan. Lucid Statement of Purpose are urgently required. Use the knowledge pool of experts globally, best practices, case studies. Example: Sustainable agri-models like agro-ecology may be able to feed the world better and longer. Agro-ecology utilises local knowledge and know-hows of farming and improves smallholder farmers&rsquo yield, income, resilience to climate change and helps meet the challenges of climate adaptation and mitigation. The recently released EAT-Lancet Commission this year outlines a planetary health diet and targets for sustainable food production that, when combined, can prevent 11 million premature adult deaths per year and help us move towards a sustainable global food system by 2050. This planetary health diet chart emphasises increasing the consumption of local, healthy, diverse diets with fresh fruits, vegetables, nuts and legumes and small portions of meat and dairy. Developing guidelines based on the planetary health diet incorporating all above-mentioned domains, and supporting the implementation of these guidelines through regulatory efforts must be prioritised.


Attaining and sustaining food and nutrition security in a changing climate requires a multi-sectoral approach involving public nutrition, agriculture, health, and social protection. There are also important links to education (especially women and children), water supply, and sanitation, as well as to cross-cutting issues like gender equality, governance etc. Leverage existing policies and strategies to advocate for greater integration and inform joint planning, objective setting and monitoring. Using appropriate financial levers and fiscal policies, people must be empowered to access healthy foods and reduce food waste and food loss. Policies should have a greater emphasis on the nutritional quality and dietary diversity of agricultural food production for local consumption. Policies must also be gender-sensitive to allow women farmers to balance their child-care responsibilities and farming.

Evidence suggests that climate-resilient agriculture can contribute to improving dietary diversity and nutrition by integrated traditional agroforestry systems which promote the sustainable exploitation of nutrient-rich forest products integrated farming systems exploiting the synergies of horticulture, aquaculture, and small livestock rearing to reduce waste and expenses on agricultural inputs and increase food production diversity. The Aid for Trade programme, initiated in 2005, is a positive example of several global institutions (e.g. WHO, FAO and the World Bank) collaborating to ensure that the health and trade sectors enhance health and development by fostering policy coherence across sectors. International trade agreements may have considerable impact on domestic food environments. Multiple sectors, ministries, departments need to talk the same language and have common vision. Leverage work done and existing resources, plan for collaborative work.

For instance, across the tribal-dominated districts of Chhattisgarh, the government has launched the Poshan Vatika scheme to raise the nutrition levels of people, especially women and children. In the same state, a new scheme - Narva (watershed management and revitalising the water table and water resources) Guruva (livestock management), Ghurva (composting and creating biogas) and Baadi (nutri-garden for home consumption) programme is being implemented through convergence between various departments such as Horticulture, Agriculture and Livestock, Panchayati Raj and Rural Development and the Forest Department. Another successful multi-sectoral project SWAN (Safe Water and Nutrition) focused on both talking about and showing communities in Vietnam that safe water and safer, more nutritious food would improve their children&rsquos health.


Demonstrate political leadership in setting national food-system strategies and initiatives with attainable time bound measurable targets. Policymakers and practitioners should capitalise upon existing knowledge, synthesised high quality evidence in form of best practices and promote positive local risk management and coping holistic strategies. Accountability must be set a priori and empowered committees should monitor periodic progress including challenges and achievements. Leaders must demonstrate practices which ensure transparency, accountability, citizen participation and inclusion, and the minimisation of conflicts of interest in policy development.


India has poor capacity to manage public health and nutrition sectors. Whether its short training programs or integrated curricula with pooled knowledge, we need to invest in awareness building, imparting relevant skill, strengthening capacity to deliver required interventions etc. Use of media and technology should be harnessed to amplify the effect. Education, communication and social advocacy around strengthening local food systems, promoting cultivation and consumption of local micronutrient-rich foods should be emphasised. Better research and development programmes to improve post-harvest management (food storage, transformation, handling, and processing) to reduce losses in quantity and nutrient content may also contribute to nutrition security. School-based approaches (school feeding programs, school gardens, nutrition education, etc.) can support child nutrition through improved WASH practices, diverse plant based diets and practical nutrition education. These early exposures help to provide a platform for sensitising both children and parents/caregivers, creating young ambassadors and future leaders.


Government action is essential to increase the healthiness of food environments, reduce all forms of malnutrition and their related inequalities. Create stringent systems to check growing influence of commercial interests on public policy development. Using technology and multiple communication channels, we must strengthen support systems, grievance redressal and provide unconditional hand holding as and when required. Designing or strengthening social protection systems to protect vulnerable population groups is also an essential component of this. Innovative example of climate risk management is the Livelihoods, Early Assessment and Protection (LEAP) project, in which the World Food Programme, supported by the World Bank, has assisted the Government of Ethiopia in the development of a comprehensive national weather risk management framework. LEAP links Ethiopia&rsquos Productive Safety Net Program to a contingency fund.

Every 1 per cent decrease in the poverty rate achieves a 0.25 per cent reduction in the malnutrition rate, a reduction of 1 per cent in undernutrition eventually yields a 4 per cent decrease in poverty. Therefore, nutritional interventions are essential to speed up the reduction in poverty. However, even if good progress is made in tackling undernutrition, those efforts could very well be neutralised by climate change if the impacts and threats of climate change to nutrition security are not properly addressed. So far, current climate change-related policies and practices have not considered agriculture, food security, social protection, health, and nutrition contexts, when in fact a more integrated approach and coherence are needed. Suposhit, Swastha, Swachh Bharat vision needs to act cohesively and urgently, especially from the sustainable environment and resilient food systems perspective.

Dr Shweta Khandelwal is Head of Nutrition Research and Additional Professor of Public Health Foundation of India

(Picture Credit: Photograph by Aron Visuals, Unsplash Photo Community)

Should fed’s dietary guidelines recommend plant-based meats?

If you want to see a lot of people become unhinged, try floating this: why not include meat alternatives such as plant-based burgers to the Dietary Guidelines for Americans recommended foods? Especially, since the recently released report from the 2020 Dietary Guidelines Advisory Committee extols the health benefits of eating a lot of vegetables and fruits.

Going one step further, why not offer these meatless burgers in school cafeterias and nursing homes? That way the children and old people could get yet another way to dine on produce.

While this line of thinking might make perfect sense to some people, especially those agreeing with the federal departments that people should limit how much meat they eat, it would, of course, cause fireworks among groups that raise livestock such as cows, pigs, chickens, and lamb. After all, in their minds — and in the minds of many consumers —meat is the backbone of a healthy diet.

This has long been a firm dietary belief in the United States. Glance through the Farm Journal’s “Famous Country Cookbook: Great Cooking for Everyday,” published in 1971, and you’ll quickly see that meat was a culinary “shining star.” In fact, the first section is titled simply “Meats.” There’s no need to adorn it with any gustatory adjectives.

Farm Journal’s “Famous Country Cookbook: Great Cooking for Everyday,” was published in 1971.

Let’s read the first paragraph of that section: “Farm women carry platters to the table for just about every meal they serve. Meat takes the spotlight three times a day in their homes, for that’s country custom, and many farmers think they haven’t had a square meal without it.”

Want to kick your appetite into gear? Try the next part of that paragraph: “Breakfast brings crisp bacon ribbons, ham slices dappled with brown, (glaze) or expertly seasoned sausage cakes — and eggs. Dinner, still served at noon, as a rule, features such favorites as roasts and steaks, with satiny smooth gravy. Supper platter specials are countless — ground beef in dozens of dress-ups has its share of champions.”

And while there are chapters devoted to “Chicken and Other Poultry,” “Potatoes,” “Eggs,” “Butter and Cream,” “Milk and Cheese,” there is no chapter strictly devoted to vegetables. How about kale? Not even an afterthought. It doesn’t seem like the recipes in this book, as delicious-sounding as they may be, would serve as a benchmark for the recent dietary guidelines.

While most people don’t even know that the federal government puts out dietary guidelines every five years, they do benefit from them. This year, the advisory team of health and nutrition experts’ report is actually a review of the latest dietary and nutrition research that the USDA and Department of Health and Human Services will use to develop the 2020-25 Dietary Guidelines for Americans. Updated every five years, the guidelines help determine federal nutrition policies and healthy eating recommendations for the nation.

Our eating habits change

Without a doubt, people’s eating preferences do change as time goes by. Doctors’ advice also changes.

In earlier years, for example, urban moms were perplexed about how they would go about persuading their children to drink 3 to 4 cups of milk each day, as was recommended by government nutritionists. Back then, milk wasn’t a common household drink, at least not in the cities. Now milk is not only cow’s milk but also almond milk, oat milk, even hemp milk. In fact, these alternative milk have grabbed 14 percent of the entire milk category— to the tune of $2 billion in the 52 weeks ending Dec. 2019, according to SPINS, a food-related data technology company.

And it wasn’t that long ago that vegetarians and vegans were brushed off as people “who ate rabbit food.” But vegetarian meal options are now offered on airplanes and at conferences. That would have been unheard of 20 or so years ago. Back then, the reaction would be “Who would want to eat a meal without meat?”

The bottom line is that federal dietary guidelines help determine federal nutrition policies and form the basis for programs such as the National School Lunch and Breakfast Programs. Starting over a century ago, the government has helped Americans make healthy food choices by providing a number of publications, food guidance symbols, and, more recently, a suite of interactive online tools.

Not that everyone will abide by the guidelines. After all, french fries and Dorito chips are tempting. But the hope is that people will substitute healthy foods such as vegetables, fruits, grains, nuts, and lean meats for junk food — at least for some of it. This, in turn, according to the dietary guidelines, will improve people’s health.

These sensible changes will mean healthier school lunches for our children, better nutritional advice for all, and progress in the fight against climate change,” said Erik Olson, Senior Strategic Director of the Health Program at the Natural Resources Defense Council.

Plenty to improve

According to the recently released advisory report, the committee’s work took place against a backdrop of several significant health issues related to nutrition in the United States.

Top of the list is overweight and obesity. The report points out that more than 70 percent of Americans are overweight or obese. More alarming than that: the prevalence of severe obesity has increased over the past two decades.

And while the high rates of overweight and obesity are a public health problem in themselves, says the report, they also can lead to prevalent diet-related chronic diseases such as cardiovascular disease, type 2 diabetes, and some types of cancer.

The report says that 6 in 10 Americans have a chronic condition and 4 in 10 Americans have 2 or more chronic conditions. And while various conditions contribute to the prevalence of these chronic diseases, prominent among these are unhealthy dietary patterns and a lack of physical activity.

We’ve heard it before. We have to eat healthy foods and exercise. Some people do that — and, of course, they’re usually healthier for it. Maybe there’s something to it. Maybe we should pay more attention to what we eat. Maybe we should check out the guidelines.

Another health-related problem is that many low-income people simply don’t have access to affordable healthy food. According to the report, in 2018, more than 37 million people, including 6 million children, lived in households that were uncertain of having or unable to acquire, enough food to meet their needs.

What they found

The good news is that you’ll reduce the risks of all causes of death if you’re an adult whose diet is higher in vegetables, fruits, nuts, legumes, whole grains, lean meats and seafood, appropriate dairy foods and unsaturated vegetable oils while being lower in red and processed meats, saturated fatty acids and cholesterol, and beverages and foods with added sugars.

Notice that they didn’t cut out meat altogether. But when it comes to beef, it needs to be lean. And a portion should be no larger than the palm of your hand or your cellphone, advise folks at the National Cattlemen’s Beef Producers Association.

As for plant-based burgers such as the Impossible Burger and Beyond Meat burgers, Danielle Beck, a policy guru, and Shalene McNeill, one of the association’s nutritionists, warn that those types of options are processed — made with a lot of ingredients. And they contain a lot of sodium.

McNeill said that while a 4-ounce hamburger has 75 mg of sodium, the Impossible Burger and Beyond Meat burgers have anywhere from 370 to 390 mg.

Burger King’s Impossible Whopper is 19g of protein, which it gets from soy and potato proteins and its fat from coconut oil and sunflower oil.

According to the Dietary Guidelines for Americans, diets higher in sodium are associated with an increased risk of developing high blood pressure, which is a major cause of stroke and heart disease.

When you hear “sodium,” think “salt,” a mineral composed primarily of sodium chloride. The bottom line, go easy with the saltshaker. Too much salt is bad for you.

McNeill and Beck also pointed out that American consumers are increasingly seeking out “natural” foods — that is, foods without a long list of ingredients. Meat fits right in with that.

In an earlier interview with Food Safety News, Washington state cattleman Rick Nelson, who has a degree in animal science, said that beef is usually “nutrient-dense,” while plant-based meats can be deficient in some nutrients.

Nutrient-dense foods are foods that are naturally rich in vitamins, minerals, and other substances and that may have positive health effects. All vegetables, fruits, whole grains, fish, eggs, and nuts prepared without added solid fats or sugars are considered nutrient-dense, as are lean or low-fat forms of fluid milk, meat, and poultry prepared without added solid fats or sugars. Nutritionists say that nutrient-dense foods provide substantial amounts of vitamins and minerals (micronutrients) and relatively few calories compared to forms of the food that have solid fat and/or added sugars.

On the other side of the fence, Impossible Foods CEO Pat Brown said that the critics of plant-based meats are missing the point

“Our product is substantially better for the consumer than what it replaces,” he told CNBC.

These new plant-based burgers and other meat options are actually directed toward meat-eaters, especially since vegetarians make up only 3 percent of the U.S. population. Many consumers say that although they eat beef, they also say they’d like to cut down on how much beef they eat.

According to a long-term study published in the Journal of the American Medical Association Internal Medicine, researchers found that swapping only 3 percent of total calories in the diet from animal to plant protein was linked to a 10 percent decrease in the risk of death.

The two most popular meatless burger alternatives are the Beyond Burger and the Impossible Burger, both of which are 100 percent plant-based and made without any animal products. The Beyond Burger’s 20 grams (g) of protein comes from peas, mung beans its fat contents come from canola oil, coconut oil , and cocoa butter. The Impossible Burger has 19 g of protein, which it gets from soy and potato proteins and its fat from coconut oil and sunflower oil.

Plant-based meats are not a passing fad. In fact, they’re a fast-growing segment of the food market. Investment firm UBS projects that the plant-based protein and meat alternatives market will increase from $4.6 billion in 2018 to a whopping $85 billion in 2030.

As for the committee’s report, Michele Simon, executive director of the Plant-Based Foods Association said she is pleased to see the Dietary Guidelines Advisory Committee follow the science on recommending a mostly plant-based diet while reducing saturated fats as well as red and processed meats.

“The science on such recommendations has been clear for decades,” she said. “We hope that science will carry the day and look forward to submitting our comments and seeing the final report.”

But when asked if the dietary guidelines should include recommendations in favor of plant-based meats, Simon said the ball is in the consumer’s court.

“We are pleased that the recommendations follow the science that we should all reduce our meat intake,” she said, “however consumers choose to make that change in their diets.”

What about food safety

Food safety is part of this, especially when considering the Food Safety Modernization Act (FSMA), which takes a preventive approach to safeguard people’s health.

Consumers play an important role in food safety. Health and nutrition experts agree that individual behaviors, along with sound government policies and responsible private-sector practices, are needed to reduce foodborne illnesses.

As for hamburgers, they have been linked to E. coli and other food pathogen outbreaks, but that’s usually because the raw meat (if it was contaminated with E. coli or other pathogens) came into contact with things like cutting boards and other foods before being cooked. Also, some people don’t cook the burgers to an internal temperature of 160 degrees, which kills the pathogens.

But raw produce — romaine lettuce, spinach, and onions, for example — has also seen its share of outbreaks and recalls associated with foodborne pathogens.

However, because plant-based meats are cooked, they don’t present the same potential health problems as raw produce.

Even so, Jaydee Hanson, Center for Food Safety, said that when it comes to food safety, consumers should treat the plant-based burgers like meat. They should be cooked to an internal temperature of 160 degrees, and they shouldn’t be eaten raw.

Washing your hands before preparing the meatless burgers and making sure the burgers don’t get contaminated by touching meat or other possibly contaminated foods, is also important.

“Pathogens that you might pick up in a kitchen could grow and contaminate the burgers,” he said.

Weighing the risks of falling ill from eating foods contaminated with foodborne pathogens, Simon of Plant-Based Foods said that “it seems pretty obvious that the risk of outbreaks we tend to see in burgers such as E.coli and salmonella is far less with plant-based burgers.”

Read the report

USDA and the Department of Health and Human Services plan to release the 2020-2025 Dietary Guidelines for Americans by the end of this year. The next edition will include advice on healthy eating from people from birth into older adulthood. The whole report can be read here.

(To sign up for a free subscription to Food Safety News, click here)

Food—How Safe?

The chief topics of discussion one midsummer afternoon in a conference room at the Centers for Disease Control and Prevention (CDC) are ground beef, eggs, salad, almonds, and cilantro. This is no conversation about the lunch menu but a review of outbreaks nationwide of disease caused by food. At the table are 26 epidemiologists—medical detectives charged with investigating the mysterious links between contaminated food and the illness it causes.

The stories are not those I expect to hear, of people getting sick from drinking unpasteurized milk or eating deviled eggs left too long in the hot sun at a picnic, but tales of people sickened by contaminated parsley and scallions, cantaloupes, leaf lettuce, sprouts, orange juice, and almonds refrigerated potato salad, eggs, chicken, salami, and beans hot dogs, hamburgers, deli meats. The food culprits were served in kitchens, restaurants, and nursing homes, on cruise ships and farms, at churches and temples, family reunions, county fairs, casinos, day-care centers. They were distributed among many towns, in many states.

According to the CDC, each year in the United States 76 million people suffer from food-borne disease 325,000 of them are hospitalized and 5,000 die. In the developing world contaminated food and water kill almost two million children a year. The epidemiologists in this room are keenly aware that behind the numbing, cold-potato statistics are real people, particularly the very young and the very old, who have suffered debilitating, even lethal, disease from what most of us consider one of life's less risky activities: eating.

On the face of it, it seems that "risk" should not be in the same sentence with "food"—that essential and wholesome component of life, so mixed and mingled with comfort, security, even love. But often it is. In recent years we've heard about the dangerous adulterants contaminating our food: pesticides on our grapes, carcinogens on our strawberries, chemicals on our apples, poisonous metals in our fish. We've heard dire warnings of the long-term effects of taking in too much fat or salt or cholesterol. In fact, in the past 30 years or so, there have been so many findings about the possible ill effects of our meals—some of them refuted shortly after being announced—that many of us have become inured to the red flags raised over food dangers.

I consider myself knowledgeable about safe eating. I thought I knew how to buy safe foods how to clean, cook, and eat them properly which dishes to order in restaurants and which to avoid. But the stories I have heard from food safety experts and the tales swapped among the epidemiologists at the CDC have swept away my assumptions. I'm starting to rethink the way I shop, cook, eat, feed my children, even the way I define food and see its place in the world.

Among the agencies that oversee the safety of the U.S. food supply is the Department of Agriculture (USDA), charged with regulating meat and poultry and foods that contain them. It also regulates pasteurized egg products. The Food and Drug Administration (FDA) addresses the safety of all other foods, including fresh produce, canned and imported foods, milk, shell eggs, seafoods, and any processed foods that do not contain meat and poultry. These agencies post periodic alerts about hazards in food—chemical contaminants, food additives, unlabeled allergenic ingredients. These are matters of serious concern. But most government officials and health experts agree: The greatest hazards today in the American food supply are not pesticide residues or dioxins or even hidden allergens but food-borne pathogens—bacteria, viruses, parasites—with the potential to harm or kill us.

Once, while on assignment for this magazine, I fell ill in an oceanside town in California after a hotel dinner of seafood and salad. That night I broke into a feverish sweat and suffered abdominal cramps and multiple bouts of diarrhea. By morning I was weak and depleted, but my symptoms were gone. If the statistics hold true, most Americans suffer in this way from time to time. We get a bad stomach for a brief spell or a bout of vomiting or diarrhea. These short-term ailments of our alimentary tracts are typically caused by viruses—often foodborne—and can spread from one person to the next by what is known as the fecal-oral route (contact with human waste and unwashed hands). The symptoms are usually mild and are gone in a day or two.

For some, however, experience with tainted food has another ending, no less chilling for its relative rarity.

A week before Christmas 1992 Lauren Beth Rudolph ate a cheeseburger from a Jack in the Box restaurant in California. On Christmas Eve, suffering from severe cramps and bloody diarrhea, Lauren was admitted to the hospital. There she endured three massive heart attacks and fell into a coma before dying on December 28. She was six years old.

The burger Lauren ate was contaminated with the virulent bacterium Escherichia coli 0157:H7. Her death was what epidemiologists refer to as an index case, the first in an outbreak that caused 732 illnesses in five states and killed four children. Every year some 73,000 Americans become ill and 60—most of them children—die from E. coli 0157:H7. The bug is a close cousin of the beneficial E. coli that normally reside in our own digestive systems. But so virulent is this version that it takes no more than a few organisms to cause deadly infection.

"We used to think of foodborne illness as little more than a stomachache," says Joseph Levitt, director of the FDA's Center for Food Safety and Applied Nutrition. "After the Jack in the Box incident we realized this was no issue of stomachaches, but a serious and compelling public health problem.'

There are 200 times as many bacteria in the colon of a single human as there are human beings who have ever lived. Most of these microbes coexist peacefully with our own cells and even assist them, helping with digestion, synthesizing vitamins, shaping the immune system, and fostering general health. Nearly all raw food, too, harbors bacteria. But the microbes that produce foodborne illness are bugs of a different order, capable of causing severe illness and even lasting damage—disorders ranging from temporary paralysis to kidney disease.

Many of these microbes are present in the animals we raise for food. When a food animal containing pathogens is slaughtered, its stomach contents or manure can taint meat during processing. Fruits and vegetables can pick up the pathogens if washed or irrigated with water contaminated with manure or human sewage.

And since a single bacterium, given the right conditions, divides rapidly enough to produce colonies of billions over the course of a day, even only lightly contaminated food can become highly infectious. The microbes can also hide and multiply on sponges, dish towels, cutting boards, sinks, knives, and countertops, where they're easily transferred to food or hands.

A century ago typhoid fever, cholera, botulism, and trichinosis were common. The incidence of these diseases has fallen, at least in the developed world, thanks to improvements in food sanitation and safety—better animal husbandry, refrigeration, the pasteurization of milk, sophisticated canning and food preservation techniques. Consumers are better educated about how to clean and cook meats and produce, and standards put in place by the federal government have largely rid dining tables in the U.S. of food that is spoiled, contaminated with filth, or derived from sick animals.

But other foodborne infections have taken the place of the old ones—among them, a troubling cluster caused by bacteria with unwieldy names: Campylobacter jejuni, Salmonella enteritidis, E. coli O157:H7, Shigella sonnei, Listeria monocytogenes. Some of these are new forms of old microbes others are the same as they've always been but are popping up in new places. The foods contaminated with this nasty set of pathogens tend to look, smell, and taste normal, and the offending microbes, we are learning, can survive the traditional heating and cooling techniques we once thought did away with them.

Growing up in the 1960s, I remember the first thing I ever tasted that I wanted to taste again was cookie dough, a sweet, melting mix of butter, brown sugar, and raw eggs. I licked the dough bowl frequently over the years with no ill effect. The wisdom used to be that one should avoid only those raw eggs with cracked shells, which might allow pathogens in.

But now food experts agree that even a perfect egg may not be safe. Salmonella enteritidis—bacteria that can cause diarrhea, cramps, fever, and, in those with weakened immune systems, life-threatening infection—can get inside the ovaries of a laying hen and contaminate her eggs before the shells are formed. Beginning in September 2001 the FDA required that all egg cartons carry a safe-handling label stating: "To prevent illness from bacteria: keep eggs refrigerated, cook eggs until yolks are firm, and cook foods containing eggs thoroughly." Soft-boiled eggs, eggs fried sunny-side up, and even softly scrambled eggs are now on the "unsafe" list along with classic versions of many egg-containing recipes touted in the cookbooks of the past few decades: Caesar salad, mousses, hollandaise sauce, French toast, omelettes, eggnog. It's not wise to make mayonnaise or ice cream with eggs at home anymore either.

In my childhood I also ate with impunity the semi-raw hamburgers served at family picnics, undercooked either because of impatient appetites or a fashion for rare meat. It's clear now that E. coli O157:H7 can survive the gentle heating we give our rare hamburgers. The USDA advises cooks at home to heat ground beef until it's no longer pink and reaches a temperature of 160 degrees Fahrenheit. The standard for commercial food services, where equipment is more reliable, is 155 degrees Fahrenheit.

Other potential troublemakers include patés, hot dogs, sliced deli meats, smoked fish, blue cheese, or soft cheeses such as Brie and Camembert because of the dangers of Listeria. This organism multiplies at refrigerator temperatures. In one study the microbe turned up on the inside surfaces of the refrigerators of two-thirds of the patients infected with Listeria. It doesn't always get into our food, but when it does, it can cause encephalitis or meningitis in people with vulnerable immune systems and, in pregnant women, miscarriage or stillbirth.

Whether the overall incidence of foodborne disease has risen over the past generation is not known because we can't track all foodborne illnesses," says Patricia Griffin, chief of the CDC's Foodborne Diseases Epidemiology Section. "What is clear is that the incidence is high, that some foodborne illnesses have clearly increased, and that dramatic changes in our food production system are likely to be playing a major role."

Until the Jack in the Box outbreak, many consumers believed that people got sick from food they didn't cook right. "Now," Griffin says, "we are more aware that the responsibility does not rest solely with the cook. We know that contamination often occurs early in the production process—at steps on the way from farm or field or fishing ground to market."

Griffin has been in the foodborne-disease business for 15 years. Her job is to look for trends in food-related illness through analysis of outbreaks. Her staff of epidemiologists at the CDC investigates outbreaks by comparing those who have become ill from food with closely matched individuals who are well and by comparing what the two groups ate. In this way they can identify both the food source of an outbreak and the contaminating microbe.

To link cases together, the scientists use a powerful new tool called PulseNet, a network of public health laboratories connected by computer that matches strains of microbes through DNA fingerprinting. PulseNet allows epidemiologists to associate an illness in Nebraska, say, with one in Texas, tying together what might otherwise appear as a sea of sporadic and unrelated cases.

Then it's the job of the investigators to track down the nature and mechanism of the contamination—what changed or went wrong in the food's journey to the table—and to determine whether to recall a particular food or to change the process by which it's produced.

In January 2000 public health officials in Virginia noted an unusual cluster of patients sick with food poisoning from one strain of Salmonella. Using PulseNet, the CDC identified 79 patients in 13 states who suffered infection from the same strain of the microbe. Fifteen had been hospitalized with severe bloody diarrhea two had died. The common factor? All had eaten mangoes during the previous November and December.

An investigation of the implicated fruit led to a single large mango farm in Brazil. When a team of health officials visited the farm, they discovered that tanks used to dip the mangoes in warm water to control fruit fly infestation, and then in cold water to cool the fruit, were open to the air. There were toads and birds around the tanks and feces in the water. It likely was the cold rinse that caused the mangoes to absorb the tank water and the pathogens it contained, including a strain of Salmonella.

It was a small problem, easily fixed. "That's one reason we investigate outbreaks," explains Griffin, "to find the little things that need to be corrected. These are not generally flukes they're problems in the way food is produced. They're likely to have happened before and—if they're not fixed—will happen again. Since the mango incident, the farm in Brazil has enclosed its warm-water tanks, and the fruit is air-cooled with fans.

But the mango outbreak had a larger lesson: In the U.S. we no longer eat only fruits and vegetables in season and grown locally, as we once did. Instead, we demand our strawberries, peaches, mangoes, and lettuce year-round. As a result, we are depending more and more on imports. Over 40 percent of all fresh fruit consumed in the U.S. comes from Mexico, Chile, Guatemala, Costa Rica, and other foreign countries, traveling hundreds, even thousands, of miles to reach our grocery-store shelves.

Eating food grown elsewhere in the world means depending on the soil, water, and sanitation conditions in those places and on the way their workers farm, harvest, process, and transport the products. (This is true, as well, for other nations that consume food exported from the U.S. Last spring, almonds from a farm in California infected 160 Canadians with Salmonella.) Because of the globalization of our food supply, the health hazards of one nation easily become those of another.

Not only do we like our foods diverse and available year-round, but we also like them convenient—prepackaged, preferably, and ready-to-eat. This means that we're leaving to commercial foodmakers the peeling, chopping, and mixing of our food. We're buying lettuce in plastic packages and potato salad, tabbouleh, and hummus in deli containers. We're eating out more: Forty cents out of every U.S. dollar spent on food is spent outside the home in restaurants and other commercial food services, where young or inexperienced, and often underpaid, workers are preparing our meals. All of this raises our risks of food poisoning. "The more untrained people handling food, the greater the risk of inadequate cooking or of cross-contamination of safe foods from unsafe or uncooked foods," notes Griffin.

We also like our food cheap. No developed nation spends less of its wealth on meals than the U.S. Advances in technology spurred by pressure to keep food prices low have shifted the balance of food production in the U.S. from many small plants to fewer but larger ones. This magnifies the extent of harm that can arise from a single failure in food safety. In fact, some of the largest and most serious outbreaks of foodborne illness have resulted not from imported foods but from the factories and farms within our own borders, which provide food to huge numbers of consumers.

A 1994 case involving contaminated ice cream constitutes one of the largest outbreaks ever recorded. Trucks transporting the premix for Schwan's, a widely distributed brand of ice cream, carried traces of raw eggs contaminated with Salmonella enteritidis. The outbreak sickened an estimated 224,000 people in 48 states.

One of the deadliest outbreaks on record involved various brands of hot dogs and cold cuts made with meat from a Sara Lee processor. The microbe, an unusual strain of Listeria, sickened scores of consumers in 1998 and was linked to 15 deaths and 6 miscarriages or stillbirths. The outbreak ended after the company recalled 15 million pounds of meat—one of the largest meat recalls in U.S. history.

In the name of efficiency and economy, we have also changed the way we raise our food animals. Our fish, cattle, and broiler and laying chickens are raised in giant "factory" farms, which house large numbers of animals in tight quarters. Griffin and others at the CDC worry that the conditions in these concentrated animal cities favor contamination and the spread of disease.

This is true in cattle feedlots, where animals are held in large groups for fattening before they're brought to slaughter. "Have you ever seen one of these places?" Griffin asks. "The cattle are jammed together, standing on black stuff, which is all feces. By the time they reach the slaughterhouse, they're covered with feces and crowded together. Even if only one animal is carrying E. coli O157:H7, under these conditions it will probably spread to others "

The Jack in the Box outbreak is a case in point. When beef is processed into ground beef, the chances of contamination rise significantly. Processing meat contaminated by one animal can spread the pathogen to all the hamburger that passes through the machinery in one day.

The USDA inspects every carcass in every meat and poultry processing plant—but without checking for microbial pathogens. "Meat inspectors still rely on sight, touch, and smell to spot disease," says Mike Taylor, former administrator of USDA's Food Safety and Inspection Service. "But the real problem in food, the bacteria that make people sick, can't be found that way."

In the summer of 1999, scientists from the USDA visited four large slaughterhouses in the Midwest to test beef cattle for E. coli O157:H7 contamination. The team found that 28 percent of the cattle entering slaughterhouses were infected and 43 percent of the skinned carcasses were contaminated. By the end of processing, however, only 2 percent of the tested meat was tainted, suggesting that measures taken by meat processors may be helping to reduce contamination.

One such measure, put in place in the past several years by food-processing companies, is a system called Hazard Analysis and Critical Control Point (HACCP) plan. This system, overseen by government regulatory agencies, scrutinizes threats to the safety of meat, poultry, seafood, and juice during processing. With HACCP, companies identify the key vulnerable points where contamination can occur in their slaughterhouses or processing plants. They must take steps to minimize the risk of pathogens invading at these points, after which they undergo government auditing.

Many U.S. meat processing plants also address contamination problems with procedures that include chemical baths, rinses, or sprays bathing carcasses in steam or irradiating processed meat to kill microbes. But while these measures have likely helped reduce the amount of contamination in meat products, it could be lower still, say scientists, if farmers reduced infection in their livestock. That's no easy task: E. coli O157:H7 is already widespread among cattle herds, and so far there's no proven, effective treatment. Researchers are exploring the possibility of using vaccines against the bug, treating livestock drinking water, even inoculating food animals with healthy gut bacteria to keep the pathogens out.

Patricia Griffin believes that finding E. coli in produce is an even more compelling argument for addressing the food-animal issue than finding it in meat. The problem arises for the most part from manure. "As a society," notes Griffin, "we're extremely careful with human feces. But cattle feces works its way into streams and groundwater, which we use to irrigate and wash our produce. Manure is also used as fertilizer. If it contains E. coli and Salmonella, we are recirculating these pathogens through our environment.

"At least you can kill E. coli in ground beef by cooking it at high enough temperatures," she continues. "But these organisms stick to produce. By washing, you can reduce contamination, but if the pathogenic organisms are there, it's unlikely that you'll get them all off. What are you going to do, not eat lettuce?"

Just how our food animals are becoming infected with these pathogens in the first place remains a mystery. But the answer may lie in what they eat.

Farmers have in the past 50 years shifted the diets of beef cattle from hay to grain in order to boost growth rates and reduce costs. "When ruminants are fed fiber-deficient rations," write USDA's James B. Russell and Jennifer Rychlik of Cornell University, "microbial ecology is altered, and the animal becomes more susceptible to metabolic disorders and, in some cases, infectious diseases."

In addition, new technologies have encouraged the feeding of a wider range of materials to cattle, including wastes. "Chickens in the U.S. eat a variety of feed, including fish meal from Asia," explains Frederick Angulo of the CDC. "Cattle eat such agricultural by-products as peanut hulls, almond shells, waste from bakeries, and poultry manure. These commodities are shipped all over the world.”

By recirculating animal by-products and waste, we may be creating new niches and opportunities for foodborne pathogens to enter the food supply and spread. In Great Britain evidence of the dangers of using animal by-products in livestock feed surfaced in the outbreak of mad cow disease, or bovine spongiform encephalopathy (BSE). The rapid spread of the illness, which likely resulted from feeding cattle meat and bonemeal from animals that already had the disease, was linked with more than a hundred cases of deadly Creutzfeldt-Jakob brain disease in humans who had consumed the infected meat. Since the outbreak among cattle in Great Britain in 1986, BSE has been found in animals in several European countries and Japan.

In 1997 the FDA banned the use of rendered remains of dead cattle and sheep in feed for U.S. ruminants, and there is no sign of BSE yet in the U.S. But many consumer groups are concerned that the government rules for animal feed include too many loopholes. Regulations still allow the use of animal blood and blood products as well as pig and horse protein. They also allow poultry to be used in cattle feed and cattle to be used in poultry feed. Is this an effective recycling of animal protein or a breach in a basic ecologic relationship—with serious consequences for our food supply?

Also present in the troughs of our food animals may be an even greater health hazard than pathogens themselves: antibiotics.

In the summer of 1998 a 62-year-old Danish woman was admitted to the emergency room at a hospital in Copenhagen after suffering diarrhea for nine days. She was diagnosed with foodborne Salmonella and immediately treated with ciprofloxacin, the antibiotic used to treat anthrax and one of the drugs of choice for Salmonella infection. But the drug did little good, and bacteria perforated her intestines. Surgery was unsuccessful, and the woman died of organ failure.

The Salmonella that infected the woman is known in the code language of epidemiologists as DT104. It is a relatively new strain that has evolved resistance to five antibiotics and sometimes shows resistance to those most commonly used to treat the infection it causes. Danish epidemiologists found the DT104 strain of Salmonella in 25 patients, all of whom had either eaten contaminated pork, handled it, or been exposed to someone sickened by it. The meat was traced through a slaughterhouse on the Danish Island of Zealand to two different swine herds. The pigs were carrying bacteria that had acquired resistance to the quinolone class of antibiotics. However, scientists were unable to determine how the pigs had become contaminated.

Farmers have been adding antibiotics to animal feed for more than half a century, after it was discovered that the drugs were effective in accelerating the growth of animals. Now by some estimates the volume of antibiotics used in animal feed equals or exceeds that used in human medicine.

"The promiscuous use of antibiotics as food supplements for farm animals is a serious threat to human health," says CDC's Alicia Anderson, an epidemiologist for the National Antimicrobial Resistance Monitoring System (NARMS). Anderson and others believe that use of the drugs in healthy animals is playing a role in changing the very nature of foodborne bacteria, creating strains that are resistant to antibiotics used in human medicine.

Since the early 1990s infections with the "superbug" DT104 and other foodborne antibiotic-resistant bacteria have turned up in several countries. A report published in 2001 after scientists at the University of Maryland and the FDA sampled ground beef, turkey, chicken, and pork from supermarkets in Washington, D.C., revealed that a fifth of the samples contained Salmonella, and 84 percent of these organisms were resistant to at least one kind of antibiotic. Some were resistant to as many as 12.

Officials in the animal drug industry argue that antibiotics are critical for keeping food animals healthy, and experts agree that overuse of antibiotics among people, not animals, is the true cause of antibiotic resistance in humans. But many scientists say that dosing animals with the same antibiotics we rely on in human medicine is a bad idea. The World Health Organization has advised against the practice, and in 1999 the European Union prohibited four antibiotics used to treat human illnesses from use as livestock growth promoters.

Three of those four antibiotics are still used to treat human illness and to promote livestock growth in the U.S. And at least 13 more are approved for both uses. "We're out of sync with the rest of the developed world in how antibiotics are used," says Anderson.

There are, however, signs of change. In early 2002, three poultry companies announced that they had greatly reduced their use of antibiotics in healthy chickens. Consumer groups and public health officials are hoping that other companies in the poultry, pork, and beef industries will follow their lead.

Government officials and industry representatives are fond of boasting that despite the many threats we have discovered, Americans have the safest food supply in the world. This may or may not be true.

There are indications that since 1996 infections from Campylobacter, Salmonella, and Listeria have dropped slightly—perhaps as a result of consumer awareness combined with new programs in government and industry to ensure the safety of meat, eggs, juice, and fresh produce. Recently government agencies and the food industry initiated a food safety curriculum for students and a "Fight BAC!" campaign to inform consumers how to keep foods safe from harmful bacteria by cleaning them, separating them, cooking them to proper temperatures, and chilling them promptly. And the FDA has launched a training program called Good Agricultural Practices to help other nations train agricultural workers and food producers in safe methods of farming, harvesting, and producing food.

But critics of the nation's food safety net say that gaps created by antiquated, inconsistent laws and regulations as well as fragmented oversight are still allowing too many pathogens to slip into our food supply. Since 1996 more people have gotten sick from Shigella, and the number of deadly E. coli infections has held steady. FDA studies completed in 2001 reported finding either Salmonella or Shigella in 12 out of 1,028 samples of domestic fresh produce, from cantaloupes to scallions, cilantro to celery to lettuce. According to the CDC contaminated eggs caused 82 percent of the cases of Salmonella enteritidis between 1985 and 1998. A study by the Consumers Union a few years ago reported that two-thirds of chickens in U.S. grocery stores carry Campylobacter, bacteria that live in the intestines of healthy birds. When the bacteria survive because of improper cooking of chickens or when cross-contamination occurs in the kitchen, they can cause abdominal pain, fever, diarrhea, and vomiting in humans.

Food is not sterile, and it cannot be made risk-free. But I'm asking myself, Do I accept some level of contamination as inevitable and increase my vigilance in the kitchen? Or do I insist on cleaner meat, poultry, eggs, and vegetables? And how far would I go to get them?

The Swedish chicken industry virtually eliminated Salmonella from their flocks by cleaning up their chicken houses and heating feed to rid it of the pathogen. Now Swedes buy Salmonella-free chickens. Are American consumers willing to pay extra for safer food of higher quality? "Many food producers say no," says Frederick Angulo, director of CDC's NARMS. "But do Americans really know that 10 percent of chickens have Salmonella and 60 to 80 percent have Campylobacter? And that 20 percent of Campylobacter is resistant to fluoroquinolones—the antibiotics of choice for treatment of Campylobacter infections?" he asks. Consumers may understand that cooking chicken properly will kill pathogens, but if they don't know how prevalent those pathogens are in the first place, can they make an informed choice about what to pay for?

Safe food is a moving target—in part because we are moving targets. Our eating habits and our ways of producing food change. We change. In this country the number of people most vulnerable to foodborne disease is growing. Within the next three decades a fifth of the population will be over 65, and many of them will be particularly susceptible to serious infection from Salmonella, Listeria, E. coli. Young children are more likely to be exposed to these bugs than they were a generation ago, not only because the production of food has changed but also because families eat out or take home prepared food more often.

And the microbes themselves are changing, evolving, taking hold in new populations, through new food vehicles, causing more or new disease. We still have limited understanding of how these foodborne pathogens work. After nearly 20 years of research, we still can't consistently treat advanced E. coli O157:H7 infections. We still are searching for clues to how food pathogens spread among cattle, egglaying hens, and broiler chickens.

How can we make safer the food and water that animals consume? How can we dispose of animal manure without threatening the environment and the food supply? How can we ensure the safety of imported foods and foods handled in our restaurants and kitchens?

These are some of the big questions that still need to be addressed to minimize our risk of infection from foodborne disease. In the meantime I am cooking my egg yolks thoroughly, washing my hands and countertops to avoid cross-contamination, and forbidding my children pink hamburger. And I am considering what choices we may have in the future about the safety of our own food, and how much extra I might be willing to pay to have my chicken guaranteed free of Campylobacter—or my salad free of deadly E. coli.

How much damage is the Porter Ranch leak doing to the climate?

Stephen Conley has flown pollution-detecting airplanes over some of the largest oil and gas fields in the nation. But never before has the UC Davis scientist encountered as much methane in the air as in recent months over suburban Los Angeles.

Over and over, Conley has flown his single-engine plane through the invisible plume billowing from an underground natural gas storage facility and into Porter Ranch to provide California air quality officials estimates of the planet-warming emissions from the leak.

On the first flight, in November, methane levels above the community jumped to 50 parts per million, so high that Conley double-checked his instruments in disbelief.

“This is probably 20 times bigger than anything else we’ve measured,” Conley said.

In three months, one failed well at Southern California Gas Co.'s Aliso Canyon storage field has spewed more greenhouse gases than any other facility in California. At its height, the leak more than doubled the methane emissions of the entire Los Angeles Basin and surpassed what is released by all industrial activity in the state.

Experts say the release of so much methane, a fast-acting greenhouse gas many times more powerful than carbon dioxide, means that the biggest environmental consequence of the leak will be its effect in boosting global warming. Long after the leak stops and the foul odors vanish, the pulse of methane will remain in the atmosphere and its damage to the climate will go on.

“It’s really moving us in the wrong direction,” said Jorn Herner, chief of research planning, administration and emissions mitigation at the state Air Resources Board.

Once the leak is stopped, air quality officials plan to complete a detailed estimate of its methane emissions using computer models and data from a network of gas analyzers on towers and buildings throughout the region. It will take months to complete an accurate measurement.

If there is any good news, it is that they show the leak rate has been declining since its peak on Nov. 28, when the well released 58,000 kilograms of methane per hour. By Thursday the rate had dropped by two-thirds to 18,400 kilograms per hour.

The utility attributed the decline to its increased withdrawals of gas from the underground reservoir, “which is helping reduce the pressure that is pushing the gas up the well and out of the leak,” gas company spokeswoman Kristine Lloyd said in an email.

As a result, she said, the reservoir has gone from being 90% full before the leak to at most 37% full on Jan. 10.

The utility does not have an estimate of the amount of gas released and says it cannot complete one until after the leak has stopped.

Crews are drilling a relief well to seal off the damaged one, with work expected to be completed by late February. Earlier this month the gas company abandoned a plan to capture and burn the leaking methane after regulators raised concerns about safety and explosion risk.

The utility has pledged to make up for its harm to the climate.

Brown has ordered state officials to draft a plan for the gas company to offset the emissions by funding projects in California to curb fast-acting climate pollutants such as methane.

“Those are significant but reasonable constraints,” said Gary Gero, senior advisor to Climate Action Reserve, a leading certifier of carbon offsets. He said the emissions from the leak are so great that the gas company would have difficulty finding enough certified offsets to cover them.

The utility would not otherwise be required to pay for its pollution because California’s climate change regulations exempt methane leaks — even enormous ones — as “fugitive emissions” that are not subject to the state’s cap-and-trade program.

estimates show the leak has put out the equivalent of 2.1 million metric tons of carbon dioxide — more greenhouse gas than 440,000 cars emit in a year. Because the surge of pollution is in the form of methane, it will have a more immediate heat-trapping effect on the atmosphere.

Natural gas consists mostly of methane. Health officials say mercaptan and other odorants added to the gas are responsible for the symptoms being reported by Porter Ranch residents, including headache and nausea. The gas also contains compounds such as benzene that can increase cancer risk through long-term exposure.

State regulators and scientists monitoring methane from the leak throughout the Los Angeles region emphasized the gas is not at concentrations that pose a health or safety risk to residents.

But its fingerprint is evident far and wide, said Riley Duren, a researcher at NASA’s Jet Propulsion Laboratory in La Cañada Flintridge. A network of gas-detecting instruments across the basin, including one sensor atop Mt. Wilson, has detected noticeable increases in methane levels as far away as Orange County and San Clemente Island, he said.

Duren thinks estimates gathered by airplane represent a “reasonable lower bound” and that total methane emissions from the leak could be higher.

The methane is leaking from one of 115 wells at the company’s sprawling facility in the Santa Susana Mountains, which stores natural gas for use across Southern California. With a capacity of 86 billion cubic feet, it’s one of the largest of more than 400 natural gas storage fields around the nation.

This is a massive leak, but it’s not altogether unexpected.

Jessika Trancik, assistant professor of energy studies at Massachusetts Institute of Technology

The incident is likely to affect regulations under development by state and federal environmental agencies to reduce methane emissions from oil and gas operations.

“This is a massive leak, but it’s not altogether unexpected,” said Jessika Trancik, assistant professor of energy studies at Massachusetts Institute of Technology, who evaluates the climate effects of natural gas-related emissions.

That’s because of a growing recognition that the nation’s natural gas infrastructure is vulnerable to leaks and other failures, particularly as it ages, Trancik said.

“It’s inevitable that parts of the supply infrastructure will fail, but the impacts of these kinds of events can be contained if we have more comprehensive monitoring and better predictions of which sites are at risk,” she said.

Studies in recent years have found emissions in the industry are significantly underestimated by official inventories. Experts blame widespread leakage, with some estimating that between 2% and 4% of the natural gas in the nation escapes into the air at some point in the production, transmission and distribution system.

Companies have spent millions in recent years improving monitoring and tightening up equipment to reduce the risks to the climate and the public, said Rob Jackson, environmental scientist at Stanford University.

“One accident like this wipes out those benefits over the past year and more,” said Jackson, who is studying the Aliso Canyon leak and thinks it is probably one of the largest in the last 50 years.

State officials might have more quickly understood the severity of the leak if they had measured its emissions earlier. The first aerial measurements came more than two weeks after the leak was reported by the gas company on Oct. 23. The Air Resources Board said it wasn’t notified of the leak until Nov. 5.

UC Davis project scientist Stephen Conley measured methane emissions from the Aliso Canyon natural gas leak on Jan. 8, 2016.

Reports submitted to the state agency show that pilot Conley made his first attempt to measure emissions from the leak the same day, working for the advocacy group Environmental Defense Fund. But Conley was sent home.

“During the two-hour flight to the site at the northern edge of the Los Angeles metro area, EDF was dissuaded from the measurement by personnel from SoCal Gas, citing extreme danger,” according to a report by the pilot. Just before reaching the facility, the environmental group ordered him to turn around, Conley said.

Conley returned two days later, under contract with the state, to complete the first successful emissions measurements.

“That’s when we discovered this absurd level,” Conley said.

The Air Resources Board released its first estimate of the greenhouse gas emissions nearly two weeks later, after what officials called an extensive review of the data.

The agency’s Nov. 20 report found that the stricken well was boosting California’s methane emissions by about 25%, underscoring “the urgency of stopping the gas leak.”

California Drought Affects Critical Mountain Snowpack

Scientists have understood the fundamental physics of climate change for almost 200 years. In the 1850s, researchers demonstrated that carbon dioxide and other naturally occurring greenhouse gases in the atmosphere prevent some of the heat radiating from Earth’s surface from escaping to space: this is known as the greenhouse effect. This natural greenhouse effect warms the planet’s surface about 60°F above what it would be otherwise, creating a habitat suitable for life. Since the late 19th century, however, humans have released an increasing amount of greenhouse gases into the atmosphere through burning fossil fuels and, to a lesser extent, deforestation and land-use change. As a result, the atmospheric concentration of carbon dioxide, the largest contributor to human-caused warming, has increased by about 40% over the industrial era. This change has intensified the natural greenhouse effect, driving an increase in global surface temperatures and other widespread changes in Earth’s climate that are unprecedented in the history of modern civilization.

Global climate is also influenced by natural factors that determine how much of the sun’s energy enters and leaves Earth’s atmosphere and by natural climate cycles that affect temperatures and weather patterns in the short term, especially regionally (see Ch. 2: Climate, Box 2.1). However, the unambiguous long-term warming trend in global average temperature over the last century cannot be explained by natural factors alone. Greenhouse gas emissions from human activities are the only factors that can account for the observed warming over the last century there are no credible alternative human or natural explanations supported by the observational evidence. Without human activities, the influence of natural factors alone would actually have had a slight cooling effect on global climate over the last 50 years (Ch. 2: Climate, KM 1, Figure 2.1).

Future Change

Greenhouse gas emissions from human activities will continue to affect Earth’s climate for decades and even centuries. Humans are adding carbon dioxide to the atmosphere at a rate far greater than it is removed by natural processes, creating a long-lived reservoir of the gas in the atmosphere and oceans that is driving the climate to a warmer and warmer state. Some of the other greenhouse gases released by human activities, such as methane, are removed from the atmosphere by natural processes more quickly than carbon dioxide as a result, efforts to cut emissions of these gases could help reduce the rate of global temperature increases over the next few decades. However, longer-term changes in climate will largely be determined by emissions and atmospheric concentrations of carbon dioxide and other longer-lived greenhouse gases (Ch. 2: Climate, KM 2).

Climate models representing our understanding of historical and current climate conditions are often used to project how our world will change under future conditions (see Ch. 2: Climate, Box 2.7). “Climate” is defined as weather conditions over multiple decades, and climate model projections are generally not designed to capture annual or even decadal variation in climate conditions. Instead, projections are typically used to capture long-term changes, such as how the climate system will respond to changes in greenhouse gas levels over this century. Scientists test climate models by comparing them to current observations and historical changes. Confidence in these models is based, in part, on how well they reproduce these observed changes. Climate models have proven remarkably accurate in simulating the climate change we have experienced to date, particularly in the past 60 years or so when we have greater confidence in observations (see CSSR, Ch. 4.3.1). The observed signals of a changing climate continue to become stronger and clearer over time, giving scientists increased confidence in their findings even since the Third National Climate Assessment was released in 2014.

Today, the largest uncertainty in projecting future climate conditions is the level of greenhouse gas emissions going forward. Future global greenhouse gas emissions levels and resulting impacts depend on economic, political, and demographic factors that can be difficult to predict with confidence far into the future. Like previous climate assessments, NCA4 relies on a suite of possible scenarios to evaluate the implications of different climate outcomes and associated impacts throughout the 21st century. These “ Representative Concentration Pathways ” (RCPs) capture a range of potential greenhouse gas emissions pathways and associated atmospheric concentration levels through 2100.

RCPs drive climate model projections for temperature, precipitation, sea level, and other variables under futures that have either lower or higher greenhouse gas emissions. RCPs are numbered according to changes in radiative forcing by 2100 relative to preindustrial conditions: +2.6, +4.5, +6.0, or +8.5 watts per square meter (W/m 2 ). Each RCP leads to a different level of projected global temperature change higher numbers indicate greater projected temperature change and associated impacts. The higher scenario (RCP8.5) represents a future where annual greenhouse gas emissions increase significantly throughout the 21st century before leveling off by 2100, whereas the other RCPs represent more rapid and substantial mitigation by mid-century, with greater reductions thereafter. Current trends in annual greenhouse gas emissions, globally, are consistent with RCP8.5.

Dog Safety: The Dangers of Blue-Green Algae Poisoning

Blue-green algae and the dangers it poses are back in the news. In August alone, the New York Times covered the subject on the national, regional and local levels.

As the articles point out, dogs are often the first alert to freshwater dangers. Their willingness to swim in and drink slimy water makes them sentinels for some of the most powerful natural poisons on earth.

A Labrador Retriever enjoying a family outing in June 2015 collapsed after swimming in a Minnesota lake. He died that day at the vet’s office. While tests were pending, the vet suspected that the dog was poisoned by cyanobacteria, also known as blue-green algae (BGA).

While most algae are harmless, some species of blue-green algae produce toxins that can kill a dog within minutes. Those that survive, or dogs who are often exposed to low levels of toxins, may develop health problems such as chronic liver disease and possibly tumors—damage that may go unnoticed until it’s severe. Humans can be sickened, too, though deaths are rare.


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Dog deaths are another matter.

As health agencies weigh the human risks that lie in recreational and drinking water from harmful algal blooms, they’ve been looking closely at animal deaths.

In New Mexico, 100 elk died in August 2013 after drinking water tainted with blue-green algae. When it comes to pets, researchers suspect many deaths are missed because people don’t even realize their dogs were exposed. Vets may not recognize the symptoms, and tests to detect the toxins can be costly and complex.

A study published in 2013 found 368 cases of dogs that died or were sickened by blue-green algae in the U.S. between the late 1920s and 2012. The authors say these “likely represent a small fraction of cases” in the U.S. each year. “The vast majority of blue-green algae associated dog deaths remain unreported and often unrecognized by owners and veterinarians.”

And the cases have surged along with the number of toxic blooms fueled by nutrients such as phosphorous and nitrogen washed into waterways from agriculture, lawns and other sources—and by climate change.

Reports of canine poisonings were sporadic until the mid-1970s, when dog deaths attributed to blue-green algae were reported “almost yearly,” the study notes.

In 2007, as drought plagued much of the country, the Minnesota lake region alone saw as many as 40 cases of canine algae poisoning, and at least four deaths. Since 2001, eleven dog deaths have been blamed on blue-green algae in California’s Humboldt and Mendocino Counties.

The earliest known case in the U.S. was in the late 1920s when a dog swam in California’s Clear Lake during an algal bloom. The dog reportedly became ill after licking “a thick coating of algae” from its fur. In 2013, another dog sickened after playing in the lake was less fortunate. this dog did not survive.

Spotting Blue-Green Algae

There are plenty of clues for telling blue-green algae—the most primitive group of algae—from harmless green, brown, and other kinds. But according to a fact sheet [PDF] from the Humboldt County Health Department, while most blue-green algae blooms don’t produce toxins, only tests can tell. “All blooms should be considered potentially toxic.” Only “a few mouthfuls of algae-contaminated water may result in fatal poisoning.”

For one thing, its color isn’t always blue-green. It can also be reddish-purple or brown, and other hues. And not all blue-green species produce toxins, while the dozens that do are only toxic at certain times. Normally, algae are equally distributed throughout the water. But excess nutrients, heat and drought make for large blooms, followed by large die offs. As it decays, toxins are released. These can still taint the water after it looks clear. Blooms may last for a week their toxins may last three weeks.

Even when blue-green algae isn’t floating on the surface, it may lurk below, moving up and down with available light and nutrients. At night it often floats to the top, forming scum. So blooms can appear overnight.

Wind and waves can then concentrate toxic blooms in shallow areas or at the water’s edge—right where dogs like to splash, wade or drink. The water doesn’t taste bad, vets say, so dogs will lap it up. Some like to gobble down dried algae mats.

After the sudden death of a dog in July 2014—hours after swimming in an Oregon reservoir—officials issued an alert, as they did in Minnesota. But toxic blooms and dog deaths were nothing new. According to Minnesota Department of Natural Resources, from 2004 through 2007, the state had reports of eight algae-related dog deaths, while toxic blooms are a familiar scourge at the Oregon reservoir.

At least 18 states have monitoring programs to detect harmful blooms. But sometimes, even advisories aren’t enough. After two dogs died within hours of drinking water from a private lake in Nebraska in 2004, state agencies acted quickly. Two weeks later, monitoring and notification networks were in place. But by the end of the recreation season there were reports of three more dog deaths, wildlife and livestock deaths, and more than 50 cases of human effects at Nebraska lakes.

The Environmental Protection Agency published a set of national standards for microcystins and cylindrospermopsin (blue-green algae toxins) in recreational or drinking water in May 2019, and promotes safety and public awareness to help protect dogs and kids.

While most algal blooms just make the water unappealing, an EPA information sheet says, “there are some real risks if dogs swim in, wade, or drink from water” with harmful algal blooms. The toxins “can sicken pets, causing everything from mild eye irritations and diarrhea to extreme health problems, including liver poisoning and even death.”

The EPA recommends that outings with pets to lakes, rivers and streams include an algae check. Dogs should not drink, swim or wade in water that is discolored, smells bad, or where there are mats of algae, foam or scum. If dogs do get into scummy water, rinse it off with tap water immediately, making sure they don’t lick algae from their fur. The toxins can also be absorbed through their skin. If a dog shows signs of poisoning, seek veterinary treatment right away. And report incidents to the Public Health Department. To avoid adding to the algae problem at home, the agency advises not over fertilizing.

According to the study of canine incidents, blue-green algae toxins can be inhaled and ingested, and exposure can induce “acute, sub-acute or chronic poisoning” in animals and people.

Most reported dog deaths involved swimming in or drinking from lakes, rivers and other fresh waters where slime was visible. In California, blue-green algae from freshwater tributaries drained into Monterey Bay, killing sea otters in 2010. Scientists were baffled by the deaths. They hadn’t known the toxins could reach the ocean. One major clue: suspicious dog deaths at a lake tainted with blue-green algae that drains to the sea.

Other dog incidents may have involved beach outings. The study of canine cases says that between 2007 and 2010, at least eight dogs developed serious or fatal liver disease after visiting Monterey-area beaches. Two of the dogs belonged to local veterinarians, but weren’t tested for the toxin that was killing sea otters.

Blue Green Algae Toxins, Symptoms and Treatment

Are water-loving dog breeds more at risk for blue-gree algae poisoning? Researchers warn that diagnosing algae poisoning is hard enough—such assumptions can lead to the wrong diagnosis. But the study did find that the most poisoning incidents involved Labrador Retrievers.

However, the “wide range” of affected dogs included Poodles, Dachshunds and toy breeds, which also encountered blue-green algae in urban and residential water bodies. These waters, often shallow and stagnant in warmer months, can have high levels of nutrients escaped from nearby yards and gardens, “providing ideal conditions for toxic blooms.”

The belief that small dogs or urban-dwelling dogs don’t encounter algae may influence the diagnoses considered. Also adding to the problem of detection and treatment, the study claims: the tests are expensive and can take weeks, access to testing may be limited, and diagnosis may not be a priority for the owner after the dog has died.

According to the algae fact sheet from Humboldt County, the toxins of concern are nervous system poisons (neurotoxins) and liver poisons (hepatotoxins). The neurotoxins can kill animals within minutes by paralyzing respiratory muscles, while hepatotoxins can cause death within hours by causing blood to pool in the liver.

The canine study mentions the many reports of animals drinking algae-tainted water “and dying within hours from neurotoxicity or hepatotoxicity, or developing sublethal chronic liver disease.”

Another less dangerous compound causes allergic responses. But initial, low-level exposure to any of these toxins may cause skin irritation and stomach upset, the study says. So those symptoms alone may not help identify the toxin.

Both nervous system toxins and liver toxins can be fatal. Liver toxins cause weakness, vomiting, pale mucous membranes and diarrhea. Common signs of neurotoxins are muscle tremors, seizures, labored breathing and difficulty moving.

Often implicated in poisonings are anatoxins (neurotoxins) and microcystins (liver toxins, considered more common and possibly carcinogenic, research suggests). Dogs are especially susceptible to anatoxins, according to the North Carolina Department of Health’s website these poisons can be fatal within minutes–or hours. Quick veterinary care with anti-seizure medication and oxygen may help.

The consensus is that there is no antidote for blue-green algae toxins. But the review of dog poisonings says that most exposed animals aren’t given specific treatment, even though “simple, cost-effective treatments may improve their chances.” In the case of microcystin exposure, since many believe that no therapies exist, owners and vets “might euthanize suspect cases or provide limited supportive care.”

After several days of veterinary treatment, a Miniature Australian Shepherd sickened by algae at a Montana lake was only getting worse. On the fifth day, her vets tried a new therapy not readily available. A 2013 report described what happened next as possibly the “first successful treatment of microcystin poisoning.”

So Many Advances in Medicine, So Many Yet to Come

After President Dwight D. Eisenhower suffered a heart attack in the middle of the night on Sept. 24, 1955, his physician told Mamie Eisenhower to snuggle with her husband in bed to keep him warm.

The physician, Dr. Howard M. Snyder, injected morphine and other drugs, none specific for a heart attack or for Eisenhower’s falling blood pressure and irregular pulse. Dr. Snyder, a general surgeon, let Eisenhower sleep until noon at Mamie’s family home in Denver, where he was staying. Then he called a cardiologist to do an electrocardiogram. Later, the president went by car to a hospital. There, he was largely confined for almost seven weeks to bed, chair rest and limited physical activity.

Eisenhower’s care shows how little doctors could do for heart attacks in 1955, three years before I entered medical school, where we were taught that medicine would be a lifetime of learning. My professors could not have known how powerful the advances that followed would be.

As a reporter for The New York Times for 37 years, I have witnessed many important medical events, from new treatments to new diseases. In reflecting on that panorama, it is clear that technology has accounted for the greatest changes in medicine. Technology has improved laboratory testing allowed for the development of CT scans, magnetic resonance imaging exams and positron emission tomography, or PET, imaging to improve diagnostic accuracy and produced new drugs and devices. Basic science, too, has deepened our understanding of disease, and much of that work depends on technology.

At the same time, the care for many ailments has been greatly improved by ancillary developments like better nursing care, newer antibiotics, transfusions of platelets to prevent bleeding, the insertion of monitoring tubes in major veins, and better organization of some services.

The gains, though, have also led to new challenges, like the risk of developing Alzheimer’s disease, strokes, arthritis and other ailments that increase in frequency with age.

When Eisenhower had his heart attack, heart disease was the No. 1 killer of Americans, and it remains so today. But more deaths would occur without these advances. Men and women with chest pain are now told to call 911, setting off an emergency response that often results in medical care within minutes, not the hours as in Eisenhower’s case.Emergency medical technicians sent to the scene can transmit electrocardiograms to a base hospital. They can inject drugs to dissolve clots and can correct potentially fatal heart rhythms at the scene or in an ambulance on the way to a hospital. These measures can stop a heart attack before it scars heart muscle.

Coronary-care units for round-the-clock monitoring were just being created during my training. Now they are standard. Doctors urge patients to become physically active as soon as possible, and most go home a few days after a heart attack.

Eating sensibly and exercising regularly are today’s central messages for preventing heart disease. A variety of drugs are widely prescribed to lower cholesterol and high blood pressure, two problems that increase the risk of heart attacks.

Angiogram X-rays can detect coronary arteries that are clogged with deposits of cholesterol and other fats. An angioplasty procedure can clear the arteries, and stent devices can keep the new channels open. Heart bypass surgery is available when angioplasty and stents will not work.

For me, an electrifying moment came in the early 1960s. Dr. Bernard Lown of Harvard reported how a shock of direct current applied to the skin over the chest at a precise point in the heart beat could safely correct a number of dangerous heart rhythms. Alternating current could not be used because such shocks were often lethal. But application of the direct current technique helped make open-heart surgery — and many other advances — possible.

In time, pacemakers came along. Now we have implanted devices that serve as both pacemakers and defibrillators. They can automatically detect a life-threatening abnormal rhythm and then shock the heart.

Vice President Dick Cheney, who had a sophisticated pacemaker and defibrillator implanted in 2001, is perhaps the most prominent recipient of these advances.

Few people appreciate that medicine has advanced more since World War II than in all of earlier history. Newer drugs and devices and better understanding of disease mechanisms have vastly improved the care of patients. For male babies born in this country in 1960, the life expectancy was 66.6 years for female babies, it was 73.1 years. In 2004, the figures, respectively, were 75.2 and 80.4. Medical advances account for much, though not all, of the gain.

As a specialist in internal medicine in the 1960s, I could prescribe about 7,000 drugs approved by the Food and Drug Administration. That number is now more than 11,700 drugs, including many new classes of medication.

Powerful drugs help patients live longer with heart failure.

The mid-1960s saw the introduction of Lasix (furosemide), a vastly more powerful diuretic than any before it. With its help, patients with heart disease and other disorders, whose bodies swelled with gallons of fluid, could eliminate the fluid through urination within hours.

Another drug, thalidomide, has gone through an amazing resurrection. In the 1960s, the F.D.A. kept thalidomide off the American market (though some doctors gave out free samples). Its use in other countries soon showed that the drug produced flipper-like arms and other ghastly birth defects among children born to mothers who took the drug as a sedative or for morning sickness. Now thalidomide is approved for a complication of leprosy, and doctors prescribe it off-label for some cancers.

Anti-rejection drugs have allowed organ transplant surgery to flourish, though no one has solved the organ donor shortage that deprives many people of a chance at longer lives.

Although doctors had measured blood pressure, few believed until the 1960s that lowering high blood pressure would prevent complications like strokes, heart attacks, loss of vision and kidney disease. In medical school, a standard therapy was the sedative phenobarbital. Now, tens of millions of Americans take more effective medications — like diuretics — to prevent these hazards.

New drugs are only part of the story. A million test tube babies would not have been born without the in vitro fertilization technique introduced in 1978. And immunizations introduced in recent years protect children against infections that include chicken pox, hepatitis A and B, measles, mumps and pneumococcal pneumonia.

As an epidemiologist at what is now the Centers for Disease Control and Prevention, I helped investigate some of the last outbreaks of polio in the United States. We used vaccine-laced sugar cubes that were easier to administer than injections in a public health emergency. I also helped investigate outbreaks of botulism, a food-borne disease produced by one of the deadliest toxins known. A few researchers mused about turning the toxin into a useful drug for serious neurological problems. That vision became Botox. But none of us dreamed that the most common use would be cosmetic, to temporarily erase the visible wrinkles of aging.

As the son of a radiologist whose office was in our home, I grew up seeing conventional X-rays displayed on my father’s light boxes. When I went to London in 1973 to report on the first brain CT scanner, I was astonished to see how it could detect tumors, strokes and other disorders that never could be seen on X-rays. I recalled all the patients with neurological symptoms who had to undergo a special X-ray procedure known as a pneumoencephalogram. In it, a needle was inserted through the back to remove spinal fluid and to inject air to outline structures in the brain. The technique was painful and unable to detect the tiny lesions that are now seen on scans.

Later versions of CT, M.R.I. and PET scanners revolutionized medical practice. These scanners have simplified the decision-making process, allowed the development of simpler and safer procedures, and eased suffering for patients.

Imaging technology also has reduced the need for exploratory surgery to detect various abnormalities. Such operations often required a long incision and a lengthy recuperation. Now, CT scans can detect an abdominal abscess, for example, and have reduced what once required three operations to one.

Better imaging has also allowed radiologists to do procedures they could not have imagined.

For me, a vivid example of that occurred when I was training as a specialist in internal medicine in the late 1960s. The patient needed scores of blood transfusions because of intermittent rectal bleeding. Standard techniques failed to detect the source of the bleeding in the bowel. An attending physician told us to stop the transfusions and let the patient die because he was depleting the blood supply. In desperation, we asked a radiologist to use new angiographic techniques to pinpoint the bleeding and stop it. The effort saved the man’s life.

Medical instruments made from fiber optics have enabled doctors to peer into many areas of the body that previously were inaccessible or that required major surgery.

One example, colonoscopy, detects intestinal polyps before they become cancerous. Another involves the repair of torn ligaments and tissues in knees and other joints.

Artificial joints are now implanted in patients whose hips and knees have been severely damaged by arthritis and injuries. Video monitors and laparoscopic instruments allow surgeons to remove diseased gall bladders through a few small incisions instead of one long cut that severed abdominal muscles and led to long and painful healing. To do the new procedures, surgeons had to develop manual dexterity and other skills entirely different from those used in traditional operations.

In ophthalmology, cataract patients once had to stay immobilized in a hospital for about 10 days. Sandbags were positioned to prevent any movement of their head to protect the newly implanted lens. Now a technique called phacoemulsification allows a lens to be implanted in a simpler cataract operation performed as an outpatient procedure.

Some major advances in surgery did not involve technology or instruments. Short-acting anesthetics like fentanyl now allow many patients to go home a few hours after an operation. In my medical school days, surgeons were learning the critical importance of monitoring fluid and vital chemicals known as electrolytes before and after an operation. Such regulation is now standard.

For breast cancer, radical mastectomy was virtually the only choice of surgery. We read studies from doctors in Canada and Europe who since 1939 had reported benefits from radiation and simpler operations for breast cancer. But our professors, virtually all men, made disparaging remarks about the quality of the work, and held dogmatically to a thesis that the more tissue removed, the better the outcome.

Then consumerism in medicine grew, more women became doctors, mammography was used more widely along with other advances to detect breast cancer earlier, and the government invested more in research on breast cancer. From these changes, doctors began to understand that the cancer was systemic and not confined to the breast. The studies documented that simpler and less disfiguring procedures, often combined with radiation and drugs, were safe treatments.

We have also learned that there are many kinds of breast cancer, lymphomas and other tumors, subtypes determined only by newer laboratory tests. This can be crucial to offering optimal therapy.

Ulcers are another ailment that doctors now understand in a new way. In 1984, two Australian doctors, Barry J. Marshall and J. Robin Warren, reported scientific evidence that the H. pylori bacterium, not stress, caused most stomach ulcers. Many doctors dismissed the finding as nonsense, and criticized me for reporting what they knew could not be true. Soon antibiotic treatment for ulcers made a rarity of the common ulcer treatment: surgical removal of parts of the stomach. In 2005, Dr. Marshall and Dr. Warren shared a Nobel Prize.

Doctors can now more effectively treat more diseases, but there are now more diseases to treat.

During my training, most professors said that all diseases were known. That hubris left doctors unprepared when AIDS came along in 1981 to cause one of history’s worst pandemics. H.I.V. has infected an estimated 60 million people and killed 25 million of them.

In 2002 and 2003, a new disease, severe acute respiratory syndrome, or SARS, spread from China to Canada and elsewhere. I began covering SARS with the first recognition of the disease and continued as scientists, in a rare World Health Organization collaborative effort, quickly identified the cause: a new coronavirus. The findings allowed health officials to act swiftly to stop the outbreak.

One of the first articles I wrote for this newspaper, in 1970, was about Lassa fever, a hemorrhagic viral infection discovered in Africa. The virus was isolated from a missionary nurse who flew to New York City from Nigeria for care. She survived. But a researcher at Yale died while trying to identify the virus. Among other new diseases are Marburg, Ebola and Legionnaire’s. Still others, like West Nile fever, have moved from one area of the world to another. For decades, the West Nile virus caused outbreaks in Africa and Europe. In 1999, West Nile appeared in the Americas, in New York City. Since then, it has spread widely and quickly through the United States and Canada to cause encephalitis and other problems.

As malaria and many other so-called tropical diseases disappeared from the United States, most doctors did not understand their continued importance in the era of jet travel, which allowed someone to become infected in one part of the world and return home before falling ill.

Eradication of smallpox has shortened the list of diseases by one. This is arguably medicine’s greatest triumph because it is the only naturally occurring disease we have wiped out. As an epidemiologist working in Africa in the 1960s, I saw lots of smallpox, and took part in the first efforts to eradicate it. In 1975, I covered its successful eradication from India.

More recent therapies have improved the outlook for many patients, but are not cures. For example, the decline in heart attacks is offset by the rise in heart failure, which, as it worsens, makes patients progressively short of breath.

And we still do not know, for example, what causes most ailments, or the precise biological mechanisms of basic life events like labor. Though doctors have long stressed the importance of prevention and public health, they and society have been slow to take strong action. Our medical school class was lucky to have a good course in preventive medicine because epidemiology was not widely taught elsewhere. To me, Berton Rouche, the New Yorker writer, arguably taught doctors more about public health than all medical schools combined through his medical detective stories about infectious and communicable diseases.

At the time, anyone who went into preventive medicine and public health was assumed to have graduated at the bottom of the class. A shingle on Park Avenue was the measure of success, not saving lives in poor countries. Now students are eager to study global health.

We may snicker over Eisenhower’s treatment. But imagine the laughter in 2056 as people look back at the brand of medicine and public health that we consider so sophisticated today. For all that doctors have learned in the last half-century, we are ignorant about far more.

Regulatory Efforts Have Been Botched

Attempts have been made to regulate antibiotic use in CAFOs better.

In January of 2012, the FDA prohibited the use of cephalosporins in food animals. This didn’t make much difference, though. That class of drugs makes up less than 1% of the antibiotics used in the U.S. on food animals every year.

A 2016 study published by researchers at Ohio State University warned of the very real potential of a post-antibiotic age after finding bacteria that was resistant to last line antibiotics on a Midwestern hog farm.

The FDA eventually took action in 2017. The rules state that farmers can no longer give antibiotics to animals for the purposes of weight gain. They also can’t buy antibiotics without the oversight of a veterinarian. Will this help? Probably. But not as much as you might hope.

Even after the 2017 attempt to crack down on CAFO antibiotic use, testing conducted at meat packing plants shows that not much has changed.

Testing on thousands of meat samples by the US Food Safety and Inspection Service (FSIS) found that antibiotics categorized as critical for human health are still in use on farm animals.

One reason for this is that, according to the Bureau of Investigative Journalism, growers can easily exploit an abundance of regulatory loopholes.

The Complexity of Current Global Food Systems and Implications for Food Safety

Today's food systems are diverse and complex, involving everything from subsistence farming to multinational food companies. Everyone eats therefore, everyone relies on food systems, local and global. The movement of food and food ingredients in food systems includes animals and animal products, plants and plant products, minerals, and vitamins. The classic cheeseburger provides an excellent example of the complexity of today's supply chain. Researchers at the University of Minnesota mapped the global supply chain of the cheeseburger working with a large quick-service restaurant chain, Figures A5-1, A5-2, and A5-3 tell the story. Figure A5-1 demonstrates graphically the movement of different commodities from the farm through processing to the restaurant. Figure A5-2 lists all the ingredients found in this company's cheeseburgers and Figure A5-3 provides an idea of the variety of companies supplying key ingredients like vinegar, garlic powder, tomatoes, beef, and wheat gluten. Each cheeseburger includes more than 50 ingredients sourced from countries in every continent of the world except the Arctic.


Global supply chain complexity. Movement of commodities. SOURCE: Shaun Kennedy, Director, National Center for Food Protection and Defense, University of Minnesota.