The CDC is warning of an increase in cyclosporiasis cases. Here’s what you need to know:
Cases of cyclosporiasis are increasing across the United States as authorities warn of contaminated produce and symptoms.
Cases of the disease, caused by a parasite that causes symptoms such as explosive diarrhea, continue to rise across the United States, but so far investigators have arrived empty-handed in determining the cause.
Cyclosporiasis is an abdominal pain caused by the parasite Cyclospora, which is commonly found in agricultural products, and has been treated primarily as a food safety issue for many years. But as health officials struggle to pinpoint the cause of the outbreak, some experts believe the focus on food may be obscuring the bigger picture.
The number of cases of the primarily seasonal illness reached at least 843 people in 31 states as of July 9, according to CDC statistics, and more than 1,000 cases when individual states reported data.
Information about past outbreaks has led state and federal health officials to warn about known culprits such as fresh herbs and lettuce, but former USDA and Food and Drug Administration officials told USA TODAY that the key to the mystery may lie in something far more universal than produce: water.
Health officials face challenges tracing food links
As USA TODAY previously reported, cystic diseases are harder to trace than foodborne illnesses such as E. coli and Listeria, with longer incubation periods, harder to detect in food and environmental samples, and less amenable to the same genetic tracking tools used for other pathogens, leaving researchers with more effort and uncertainty.
An additional challenge is what Kalmia Kneel, a professor of microbial food safety at the University of Delaware, describes as “reduced oversight” at the federal level.
Last year, the CDC scaled back a decades-old federal and state partnership monitoring foodborne illnesses, including those caused by Cyclospora. The move eliminates the need for authorities to report Cyclospora and six other pathogens to the Foodborne Disease Prevention and Surveillance Network, known as Foodnet.
Losing such data could prevent health officials from tracking cases across the country and identifying trends linking cases, such as certain types of produce or food producers, Kneer said. This could risk delaying authorities’ ability to identify the cause of the outbreak and stop further transmission.
“We have much less information to work with,” Knier said. “I think we’re seeing some of the effects of that now.”
In response to USA TODAY, the FDA said, “Under Secretary Kennedy’s leadership, FDA is currently investigating the Cyclospora outbreak using established epidemiological, laboratory, and tracking tools, working closely with CDC and state and local partners.”
“Protecting the nation’s food supply is FDA’s core responsibility, and FDA has the expertise, personnel, and resources necessary to detect, investigate, and respond to foodborne illness outbreaks and take regulatory action when necessary.” The CDC did not respond to USA TODAY’s request for comment on July 10.
But food may not be the real origin
But some experts say that with so much focus on food, researchers are missing a big piece of the tracking puzzle.
“The role of water in the transmission of Cyclospora to humans is probably underappreciated, underappreciated, and poorly understood,” Frank Yiannas, former deputy assistant secretary for food policy and response, told USA TODAY. “There have been several large outbreaks associated with produce in the United States, and water is likely, and in some cases proven, to have been a conduit for produce contamination.”
Water acts as a kind of delivery system for pathogens to reach our produce. Contamination that causes food poisoning often begins in irrigation systems, soil, and the environment in which food is grown.
Waste, both human and non-human, enters waterways where it should not flow, such as sewage leaks, wastewater overflows, septic system failures, floods and surface waters (rivers, canals, reservoirs, rivers). When that fecal-contaminated water flows into irrigation systems used to grow food, Cyclospora remains on crops and can infect humans if eaten raw.
In one investigation conducted during Yiannas’ tenure at the FDA, the agency traced the outbreak to red cabbage grown in South Florida, where two years of testing found Cylospora “easily spread” in canals used by local farmers to irrigate their crops.
Cyclospora is also quite resilient and is not killed by chlorine, the main disinfectant used in city water supplies, Dr. Robert Mandrell, a microbiologist and former USDA official, told USA TODAY.
“This parasite is very resistant,” he said, noting that the parasite’s tough outer shell allows it to survive conditions that would kill many other pathogens. “When you treat water in a wastewater facility, you expect it to be able to withstand that chlorine.”
Floods, sewage and wastewater could be key
Mandrell noted that Michigan and Ohio, two of the states with the highest numbers of cases, have recently experienced heavy rains and flooding, and said people don’t have to get infected simply by eating crops grown in contaminated water.
When heavy rains cause sewage systems or septic tanks to overflow, untreated or partially treated sewage can mix with the floodwaters, spread to neighborhoods, fields, waterways, low-lying areas, and eventually filter into recreational areas such as waterways, wells, and reservoirs. This can result in more direct exposure than the water-to-food route.
“It may not be the drinking water that’s contaminated, but we don’t know. It could be that it’s contaminated in some cases, but it’s also possible that they were just exposed to flood water that had some level of sewage in it,” Mandrell said. However, many of these things are not certain because monitoring for Cyclospora in water sources is far from routine or thorough in the United States.
“We need to do a major study of not just our drinking water, but also the rivers and streams that drain our wastewater,” he said.
Yiannas said isolated cases have proven that this is possible. In one case, a cyclosporiasis infection was traced to tap water in a dormitory. In another case, a child was infected while swimming in Lake Michigan, and in yet another case, a man was infected while cleaning sewage.
Still, the nature of the parasite makes it more difficult to study than other foodborne pathogens, and there is much scientists and health officials don’t know, they said.
Why do parasites remain a mystery?
Although scientists understand how Cyclospora makes people sick, they still don’t fully understand how Cyclospora moves through the environment before reaching people, and under what environmental conditions and through what processes it transforms into an infectious microorganism, Mandrell explained. They are notoriously difficult to find in environmental samples, and have unique reproductive characteristics and a life cycle that is nearly impossible to reproduce in the laboratory.
In the face of outbreaks like this one, both Mandrell and Yiannas said U.S. public health agencies need to invest more energy and resources into researching Cyclospora and its potential for waterborne transmission. In fact, Yiannas said, the survey the FDA uses to track commonalities among sick people for possible sources of infection did not yet include a question about water the week of July 6.
“When we’re investigating these outbreaks, we’re not asking enough questions about it,” he said. “We don’t have a lot of data, so we should.”
The FDA and CDC did not respond to USA TODAY’s questions about water tracking.
Cyclospora was also previously thought to be an imported food problem, and still is, at least to some degree, but Mandrell said that even though this outbreak can be traced back to imported food, it is now likely also a domestic problem.
“We say it’s not endemic, but we don’t know for sure,” he says. “As I said, given the amount of waste that is being produced during this outbreak, where is it going?”
Yiannas agreed, saying, “I think this parasite is now endemic in the United States, and I think it would be foolish to simply assume that it’s a food from another country.”
“If we can’t solve this epidemic, I think it’s going to really test the effectiveness of our public health system,” he says.
In the meantime, Mandrell said people in high-flooding areas can switch to bottled water until conditions dry out if they have concerns about their water supply.
“If you want to be proactive, you might just stay away from the water if you’re worried, especially if you can see something clearly contaminated outside your window,” he says.
Christopher Kang, USA TODAY, Contributor
