White House denies that CDC cuts affected parasite outbreak
White House Press Secretary Karoline Leavitt said the CDC and FDA “have the resources they need” to combat an outbreak of a diarrhea-causing parasite.
As a cyclosporiasis outbreak continues to impact thousands of people across the United States, some, especially those who have already been infected, may be wondering if developing immunity to the “explosive” diarrhea-causing parasite is possible.
According to health officials, including the New York State Department of Health, the answer is no: A previous infection of the Cyclospora parasite does not make a person immune. Individuals can be reinfected with cyclosporiasis if they are exposed to the parasite again, per the New York-based government agency.
The current outbreak has sickened thousands of people across the country. Michigan health officials reported more than 4,300 cases statewide and at least 102 hospitalizations since June 22, with cases also reported in 34 other states. Federal officials have said clusters in Kentucky, Michigan, Ohio and West Virginia are likely connected.
An investigation by the Centers for Disease Control and Prevention, the Food and Drug Administration and state health officials linked shredded iceberg lettuce served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia to the outbreak of the stomach-churning parasitic infection. The investigation identified a single supplier of iceberg lettuce from Mexico used by the suspected Taco Bell locations, the agencies announced on July 16.
“Based on ongoing conversations with public health officials, and out of an abundance of caution, Taco Bell has taken immediate action to voluntarily remove potentially impacted lettuce from a supplier in select states,” the fast-food company said in a statement following the investigation, adding that lettuce supplied by the unidentified vendor will be “indefinitely removed” and replaced within 24 hours in affected states.
Here’s what experts are saying about possible immunity to cyclosporiasis amid the growing outbreak.
‘Assume you do not have immunity,’ doctor says
Dr. Brian Yuen, a physician with Inova GoHealth Urgent Care in Virginia, told USA TODAY that while immunity to cyclosporiasis is theoretically possible, it is not something people in the United States should rely on. “The safest answer is to assume you do not have immunity after one exposure in a non-endemic area like the United States,” he said.
Additionally, Dr. Susan Cheng, a trained infectious disease epidemiologist and associate dean at Tulane University, shed some light on possible immunity, saying, “Because cyclosporiasis primarily attacks and stays in the gut, it does not travel in the bloodstream the way that some other infections might, which means it does not interact with the immune cells that create a lasting memory of previous infection.”
“The immune system in the gut isn’t as equipped to remember infections because its primary response is to shed the pathogens out of the body,” she added.
Why Cyclospora may not create lasting immunity
How the parasite behaves in the body is partly why creating lasting immunity to the infection is difficult, according to health officials.
Cyclospora is a microscopic parasite that infects the intestinal tract and can cause prolonged diarrhea. People become infected by consuming food or water contaminated with the parasite.
A National Library of Medicine review by researchers Maria Yazdanbakhsh and David Sacks explains that parasites often develop immune evasion strategies that allow them to survive in the human body. These strategies can include changing their surface features, altering immune signals or triggering regulatory responses that prevent the immune system from fully clearing them.
Cheng said Cyclospora presents its own challenges because much of its life cycle occurs outside the human body before it becomes infectious. “This makes it tricky to train our immune systems, as it is already infectious when it enters the body and our immune systems have less time to develop defenses against it,” she said. “Since it is not a virus, it is also challenging to develop a vaccine against it, and a vaccine does not currently exist.”
Symptoms and treatment
Cyclosporiasis most commonly causes watery diarrhea that can last from several days to a month or longer, and symptoms may disappear before returning. Other symptoms include nausea, vomiting, stomach cramps, fatigue, weight loss, muscle aches and loss of appetite.
Doctors diagnose the illness through laboratory testing of a stool sample. Treatment typically involves the antibiotic trimethoprim-sulfamethoxazole, while people with diarrhea are also encouraged to rest and drink plenty of fluids.
How to reduce the risk
Health officials say cyclosporiasis outbreaks in the United States have previously been linked to contaminated fresh produce, including cilantro, salad mixes, basil, snow peas and raspberries.
The New York State Department of Health recommends washing hands before and after handling produce, rinsing fruits and vegetables under running water, cutting away damaged areas and refrigerating prepared produce promptly.
Travelers visiting areas with poor sanitation are also advised to drink water from safe sources, including sealed bottled water, boiled tap water or sealed carbonated drinks.
Until investigators identify the source of the outbreak, Cheng said people who have already had cyclosporiasis should not assume they are protected from getting sick again. She recommends avoiding bagged salads, leafy herbs and greens, along with fruits and vegetables that cannot be thoroughly washed or cooked until health officials identify the contaminated food source. She also advised people to be mindful of fresh produce served at restaurants and in takeout meals while investigators work to identify the source of the outbreak.
Contributing: Katie Wiseman & Thao Nguyen/ USA TODAY
National Trending Reporter Anthony Thompson can be reached at ajthompsonUsatodayco.com, or on X @athompsonUSAT.
Mike Snider is a national trending news reporter for USA TODAY. You can follow him on Threads, Bluesky, X and email him at mikegsnider & @mikegsnider.bsky.social & @mikesnider & msnider@usatoday.com.