The United States is going through the largest cyclosporiasis outbreak on record. Thousands of people, mostly in the Midwest, have fallen sick with stomach cramps and severe diarrhea. The authorities have linked the food-borne illnesses to lettuce grown in Mexico and served at some Taco Bell locations.<\/p>\n
My colleagues on the Well team have been covering the race to trace the source of the outbreak<\/a>, and it took a twist this week.<\/p>\n On Saturday, the Food and Drug Administration announced that lab tests had confirmed cyclospora contamination in iceberg lettuce from Mexico. The company that runs the operation, Taylor Farms, issued a recall based on other epidemiological evidence and then expanded it after the lab test came in. But then, on Sunday, the F.D.A. said the test had been a false positive. Taylor Farms is still a focus of the investigation<\/a>, and the recall remains in effect.<\/p>\n It\u2019s still not clear whether climate change played a role in the current outbreak. Cyclospora is a parasite that spreads through human feces<\/a>, and it\u2019s rare for investigators to pinpoint a precise source of contamination.<\/p>\n But experts say it\u2019s plausible that warming could contribute to an increase in cyclospora illnesses. Don Schaffner, a food microbiologist at Rutgers University, told me that cyclospora tends to grow in the spring and summer, so higher temperatures could extend its season. In previous cyclospora outbreaks, investigators have theorized<\/a> that heavy rainfall might have somehow caused human waste to seep into irrigation water, contaminating crops.<\/p>\n Whether or not this outbreak was directly linked to climate change, we know that warming is expected to fuel the spread of a wide variety of food-borne pathogens. And the current episode has exposed potential vulnerabilities in public health detection systems at a time when the need for accurate monitoring of the food supply is only growing more important.<\/p>\n Higher temperatures, more illness<\/p>\n According to the World Health Organization, some 600 million people get sick each year from eating food that has been contaminated with bacteria, parasites or viruses. Scientists have predicted that climate change will drive caseloads higher<\/a> in many parts of the world.<\/p>\n Higher temperatures and more rain tend to correlate with increases in illnesses from pathogens like salmonella and campylobacter. That\u2019s the case in part because germs can multiply faster in hotter weather. Salmonella, for example, is happiest when the temperature is in the 90s Fahrenheit, when it can grow quickly in animals or on food. A 2014 study found that, in Mississippi, a temperature increase of 1 degree Fahrenheit<\/a> was associated with an increase in salmonella cases.<\/p>\n Warming oceans pose an emerging food safety risk, too. A 2024 paper found that climate change is \u201cundeniably\u201d contributing<\/a> to the spread and prevalence of a family of bacteria known as Vibrio, the most infamous of which is the flesh-eating bacteria Vibrio vulnificus. People can get Vibrio infections from eating raw seafood or swimming in contaminated water.<\/p>\n Dry summers and heavy rainfall can each also increase pathogen spread. During droughts, more dust can float through the air, spreading bacteria across farms. On the other hand, torrential rain can distribute germs by spreading human and animal waste from one place to another. Tropical storms, which can be intensified by climate change, are associated with big spikes in E. coli infections<\/a>.<\/p>\n The \u2018big concern\u2019 for public health<\/p>\n It\u2019s exceedingly uncommon for the F.D.A. to retract an announcement<\/a> of a positive lab test. Dr. Schaffner said the agency may have made the statement too early, before it completed confirmation testing.<\/p>\n \u201cNow they\u2019ve got egg on their face, and nobody\u2019s happy,\u201d he said.<\/p>\n In a statement, an F.D.A. spokeswoman, Emily Hilliard, said the Trump Administration has mounted a robust response to the outbreak and has provided Americans with the information they need to protect themselves.<\/p>\n But the back-and-forth has been confusing for people trying to understand which foods to avoid. The retraction didn\u2019t mean the focus of the investigation had shifted away from Taylor Farms or lettuce, but the company issued a statement saying<\/a> \u201cF.D.A. apologized to us.\u201d The agency said it had not apologized<\/a>, according to news reports.<\/p>\n \u201cThe big concern I have about the flip-flop is also the impact it has on trust,\u201d Dr. Susan Mayne of the Yale School of Public Health told my colleagues<\/a>. \u201cChanging such an important determination certainly raises questions,\u201d she added.<\/p>\n Federal cuts to health funding may be playing a role<\/a> in hampering the response to this outbreak. State and local health departments, which rely on federal support to monitor and respond to food-borne illnesses, received less than half the money they requested this year.<\/p>\n Until recently, several states were required to track and report cyclospora cases to a national database. But last year, the Centers for Disease Control and Prevention made this voluntary. Incomplete data may have made it harder for officials monitoring the database to identify the outbreak.<\/p>\n \u201cIt certainly doesn\u2019t strengthen our ability to do anything about cyclospora,\u201d Dr. Schaffner said.<\/p>\n Join us for a day of live journalism<\/p>\n