August 4, 2026

expert reaction to Cyclospora outbreak in US and Mexico

Scientists comment on a Cyclospora outbreak in the US and Mexico.

Dr Brian Rice, Infectious Disease Epidemiologist and Senior Lecturer at the University of Sheffield’s School of Medicine and Population Health, said:

“Cyclosporiasis is something travellers should be aware of, but I would not want people to be unnecessarily alarmed. We are seeing an increase in reported cases in the United States, although surveillance figures need to be interpreted with some caution, and investigations into the reasons for this increase are ongoing.

“The infection is acquired by swallowing Cyclospora parasites in contaminated food or water, rather than through normal person-to-person contact. For travellers, sensible food and water hygiene remains a pragmatic precaution.

“My own research has looked at infections acquired by British people while travelling abroad, and has highlighted the importance of incorporating travel into routine infection prevention advice. The key message is not that travel itself should be avoided, but that travellers should be aware of the infections they may encounter and take appropriate precautions.

“There is no current reason to suggest that people should avoid travel to the United States or Mexico, or avoid fresh fruit and vegetables altogether, provided they follow good food and water hygiene practices.

“The current US investigation has identified a possible association with iceberg lettuce supplied from Mexico, but this should not be interpreted as meaning that Mexican food or travel to Mexico is generally unsafe.

“Foodborne outbreaks can be challenging to investigate, and epidemiological evidence can point towards a likely source even when the parasite itself is not detected in food samples.

“Anyone who develops persistent or recurrent watery diarrhoea during or after travel should mention their travel history to their healthcare provider. Cyclospora can cause prolonged illness, and specific testing may be needed.”

Declared interests

Dr Brian Rice: None received

For all other experts, no reply to our request for DOIs was received.