CDC Investigates Cyclospora Outbreak Causing Explosive Diarrhea in 18 States

The U.S. Centers for Disease Control and Prevention (CDC) is investigating a surge in cyclosporiasis cases caused by the parasite Cyclospora, with more than 400 cases reported across 18 states as of early July 2026. The illness, characterized by watery and sometimes explosive diarrhea, has led to at least 20 hospitalizations but no deaths Source: The Guardian.

The Pathogen

Cyclospora spreads through raw produce or water contaminated with human feces. Symptoms include cramps, nausea, fatigue, and low-grade fever. The disease is not usually life-threatening and is not transmitted person-to-person Source: The Guardian.

Outbreak Scale

Between May 1 and June 16, the CDC recorded 145 cases across 17 states, with 20 hospitalizations. However, Michigan alone has reported over 300 cases since June 22—far exceeding its typical annual count of about 50 Source: The Guardian. New York has seen 107 cases since May 1, with NYC cases roughly doubling year-over-year Source: Ground News. Other hard-hit states include Texas, Illinois, and Michigan. A total of 18 states have reported cases, including Alaska, Colorado, and Florida Source: The Guardian.

Investigation and Response

The CDC, FDA, and local officials are investigating multiple clusters; there is no evidence of a single multi-state outbreak linking all cases Source: The Guardian. The parasite is seasonal, with peaks from May to August, and past outbreaks have been linked to fresh produce like basil, cilantro, and berries. The CDC advises thorough washing of produce and hands, and seeking medical care for symptoms Source: The Guardian.