Alert in the United States: Cases of «Explosive» Diarrhea Rise Across 17 States

• Cyclospora outbreak expands across 17 states.
• Officials investigate a possible contaminated food source.
• Diarrhea can last for weeks without treatment.

An outbreak of cyclosporiasis, an intestinal illness caused by the Cyclospora parasite, has put health officials across the United States on alert after a seasonal increase in cases across at least 17 states.

The Centers for Disease Control and Prevention (CDC) are investigating whether the infections are linked to a common source of contaminated food, while several state health departments continue reporting expanding outbreaks.

CDC investigates possible source of the outbreak

The rise in cases coincides with the parasite’s peak season, which typically runs from May 1 through August 31 each year.

According to the CDC, 145 domestically acquired cases were confirmed in the United States between May 1 and June 16, 2026.

An additional 45 people became ill after traveling outside the country before developing symptoms.

In total, health officials recorded 190 cases through June 16.

At least 20 people required hospitalization.

No deaths related to the illness have been reported so far.

Federal health officials are working with state agencies and the Food and Drug Administration (FDA) to determine whether the illnesses share a common food source.

«Local, state, and federal public health authorities (CDC, FDA) are investigating multiple clusters of cases across more than one state. Investigations to identify possible sources are ongoing.»

Experts also warn that the actual number of infections is likely higher than reported.

Many people experience mild symptoms, recover without medical care, and are never tested specifically for Cyclospora.

Michigan reports one of the largest Cyclospora outbreak clusters this summer

While the nationwide investigation continues, Michigan has reported one of the sharpest increases in recent weeks.

On July 1, state health officials announced a sudden spike in cases.

Several local health departments have launched active investigations into an outbreak that continues to expand.

According to the Michigan Department of Health and Human Services, more than 170 cases were reported in just nine days.

The infections are spread across seven counties.

• Monroe: 70 cases.
• Lenawee: 33.
• Washtenaw: 21.
• Wayne: 12.
• Jackson: 7.
• Shiawassee: 7.

An additional 24 cases have been reported across 11 other counties and the city of Detroit.

«Cyclospora outbreaks have been reported across the United States, and now here in Michigan as well,» said Dr. Natasha Bagdasarian, the state’s chief medical executive.

«Given the unusual number of cases identified in just over a week, we expect more cases to be reported. We encourage Michigan residents to contact their healthcare provider if they experience sudden, persistent diarrhea and to notify their local health department if others in their household develop similar symptoms.»

Officials emphasized that they are still determining whether all recent cases are connected to the same outbreak.

What is cyclosporiasis, and why are experts concerned?

Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

According to the Illinois Department of Public Health, it is «a single-celled parasite too small to be seen without a microscope.»

People typically become infected by consuming contaminated food or water.

The CDC says researchers still do not fully understand how the parasite contaminates food.

However, it has most often been linked to fresh fruits and vegetables.

Foods previously associated with outbreaks include: Raspberries, peas, mixed lettuce, basil, cilantro.

Health officials also note that the illness follows a seasonal pattern.

Each spring and summer, infections increase in several regions of the country.

For that reason, public health agencies recommend taking extra food safety precautions during these months.

«Explosive» diarrhea can last for weeks

One of the hallmark symptoms is watery, «explosive» diarrhea.

However, the illness can also cause a variety of gastrointestinal problems.

According to the Cleveland Clinic and the CDC, symptoms may appear several days—or even weeks—after consuming contaminated food or water.

Dr. Irfan Hafiz, an infectious disease specialist at Northwestern Medicine, explained that the illness differs from many other intestinal infections because of its duration.

«The symptoms are less intense, but they last longer. Norovirus hits hard and then goes away. This illness, by contrast, continues over a much longer period.»

The CDC added that, without treatment, symptoms may persist for weeks.

«Without treatment, symptoms can last from a few days to a month or longer.»

«Some symptoms, such as diarrhea, may improve and then return. Others, such as fatigue, can continue even after gastrointestinal symptoms have resolved.»

Health officials also noted that some infections may occur after exposure to contaminated recreational water.

Dr. Hafiz said swimming in lakes, ponds, or water parks could represent another potential source of exposure if the water is contaminated.

How to prevent cyclosporiasis and recognize the symptoms

While investigators continue searching for the source of the Cyclospora outbreak, health officials say basic hygiene practices can significantly reduce the risk of infection.

To help prevent cyclosporiasis:

• Wash fruits and vegetables thoroughly before eating them.
• Wash your hands before and after handling food.
• Drink safe water and avoid potentially contaminated water sources.
• Practice proper food hygiene during preparation.
• Seek medical attention if you develop persistent diarrhea or if several people in your household experience similar symptoms.

Common symptoms include:

• Watery or «explosive» diarrhea.
• Loss of appetite.
• Weight loss.
• Abdominal cramps.
• Bloating.
• Excess gas.
• Nausea.
• Prolonged fatigue.
• In some cases: vomiting, low-grade fever, headache, muscle aches, and flu-like symptoms.

When should you seek medical care?

• Diarrhea lasts for several days or worsens.
• You develop signs of dehydration.
• Multiple people who shared a meal become ill.
• Symptoms return after initially improving.

Health officials continue investigating the source of the outbreaks and encourage the public to follow official updates as the investigation progresses in the affected states.

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SOURCE: KKTV / Telemundo