Diarrhea Parasite Spreads Across the US

Topic: Disease Outbreak

Wednesday, August 5, 2026, at 1:02 pm

Cyclospora is a parasite that causes diarrhea, nausea, and vomiting.

A parasitic infection that causes diarrhea has spread across over a dozen US states after officials blamed contaminated lettuce for the outbreak.

A record number of cyclospora cases have been reported in over 30 US states, but experts say not every illness is likely caused by a single source.

The Cyclospora parasite causes diarrhea, nausea, and sometimes vomiting; without treatment, symptoms can last over a month.

The US Centers for Disease Control and Prevention has linked the outbreak to nine states.

Local media predict the number of states will soon increase to at least 15.

At least two deaths have been reported in Michigan, the first fatalities associated with the outbreak.

What is Cyclospora?

Cyclosporiasis is an intestinal infection from consuming contaminated food or water.

The microscopic parasite is transmitted via fecal matter.

It is difficult to detect, according to Professor Shokoofeh Shamsi.

It's easy for the parasite to infect us, she said.

Children, older people, and those with weak immune systems are at risk of serious illness.

The people who died had underlying health conditions that may have been impacted by dehydration and the infection.

Any time we get complacent, an outbreak happens, Professor Shamsi said.

The US is unable to control this outbreak.

How did this Cyclospora outbreak start?

The Food and Drug Administration linked the outbreak to iceberg lettuce from central Mexico.

The lettuce was served at Taco Bell locations in multiple states.

Taylor Farms has announced a recall for the lettuce products sourced from Mexico.

The same supplier was linked to a 2013 Cyclospora outbreak.

An investigation into reported cases and contaminated products is ongoing.

Former FDA commissioner Scott Gottlieb said weather conditions raised the risk of contamination.

Raw sewage could have reached farmed areas through flooding or a breach.

There was an event in central Mexico that we don't know about yet, he said.

Analysts in Mexico are waiting for the results of official investigations.

While most cases are linked to Taylor Farms, at least two other outbreaks have an unknown source.

Democratic congressman Josh Gottheimer blamed cuts to the FDA and CDC for the lack of surveillance.

Mr. Gottheimer said the CDC fired more than 70 percent of the team responsible for tracking Cyclospora.

How many cases of cyclosporiasis have been recorded?

As of August 3, the CDC had received reports of 10,468 cases.

An additional 12,255 cases are still unconfirmed.

To date, 47 states have reported cases, and at least 517 people have been hospitalized.

Dr. Gottlieb believes cases are being under-reported.

The true number is likely 10 to 20 times what has been recorded.

This is the largest outbreak we've ever seen in the history of Cyclospora.

In Michigan, officials have recorded 11,508 total cases.

The CDC does not include probable cases, so numbers vary.

Michigan's chief medical executive, Natasha Bagdasarian, said local health departments are interviewing patients.

The information is being entered into a statewide database.

There's a lot of tracing back that we have to do, Dr. Bagdasarian said.

It's not just where people got their produce from, but tracing it back to its origins.

How do you control the spread of Cyclospora?

For a single-celled organism, cyclospora is really difficult to kill.

The only thing that is 100 percent effective is high temperature and proper cooking.

But we don't want to cook our salads, and it's recommended to consume raw vegetables daily.

It's not only on the public to be aware, but on policymakers to have a well-designed supply system.

And if the parasite does make it through, they need proper surveillance and monitoring.

There have been no outbreaks of cyclosporiasis in Australia.

Sporadic cases have been associated with international travel.

See more ABC coverage.

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