The United States Centers for Disease Control and Prevention has issued a health advisory following a sharp rise in cyclosporiasis cases across multiple states.
Since May 1, 2026, health officials have recorded 1,645 confirmed domestically acquired cases of the intestinal illness in 34 states.
The CDC is also reviewing more than 5,100 additional cases to determine whether they are domestically acquired Cyclospora infections.
Cyclospora Cases Rise Sharply in 2026
The latest figures represent a major increase compared with the same period last year.
By mid-July 2025, 249 cases had been reported nationally.
Health officials say the true number of infections could be higher because cyclosporiasis is often underdiagnosed and underreported.
The CDC, Food and Drug Administration and local health authorities are investigating several clusters of infections.
141 Patients Hospitalised
Among confirmed patients with available information, 141 people, representing about nine per cent, were hospitalised.
No deaths have been reported.
Patients range from two to 95 years old, with a median age of 44.
Health officials said 56 per cent of confirmed patients were female.
What Is Cyclosporiasis?
Cyclosporiasis is an intestinal illness caused by a microscopic parasite known as Cyclospora.
People can become infected after consuming food or water contaminated with the parasite.
The illness is not usually spread directly from one person to another.
Previous outbreaks have been linked to contaminated fresh produce.
Symptoms of Cyclospora Infection
Symptoms usually begin about one week after exposure, although illness can develop between two and 14 days after infection.
The most common symptom is frequent watery diarrhoea.
Other symptoms may include loss of appetite, weight loss, bloating, nausea and tiredness.
Some patients may also experience a mild fever or vomiting.
Without treatment, symptoms can disappear and return repeatedly for weeks or longer.
CDC Investigates Possible Common Sources
Health authorities are investigating multiple clusters to identify the sources of the infections.
One outbreak involving more than 400 cases across at least four states appears to be epidemiologically linked, suggesting a possible common source.
However, officials have not identified one source responsible for all reported cases.
Investigations and food traceback efforts are continuing.
CDC Advises Public to Wash Fresh Produce
The CDC has advised people to thoroughly wash fresh fruits and vegetables under clean running water before eating them.
Consumers should follow safe food handling practices even when produce is labelled as pre-washed.
Health officials warned that chemical sanitising methods may not completely remove Cyclospora from contaminated produce.
People With Prolonged Diarrhoea Urged to Seek Medical Care
People experiencing prolonged or frequent watery diarrhoea are advised to contact a healthcare professional.
Doctors may need to specifically request laboratory testing for Cyclospora because routine parasite tests may not always detect the infection.
Patients with severe diarrhoea should also stay properly hydrated.
Health Officials Monitor Rising Infections
The sharp increase in cyclosporiasis cases has placed health authorities on alert during the annual Cyclospora season, which typically runs from May through August.
The CDC and other health agencies are continuing investigations to identify possible food sources and prevent further infections.
As investigations continue, health officials are urging the public to practise safe food handling and seek medical attention when persistent symptoms develop.
