Michigan health officials are tracking a cyclosporiasis outbreak that has infected approximately 4,000 people since June 2026 [1, 4].

The scale of the outbreak represents a significant public health challenge, as the parasite causes severe intestinal distress and has led to more than 100 hospitalizations in Michigan [1].

Cyclosporiasis is a parasitic illness characterized by severe watery diarrhea. Health officials said the symptoms are "explosive" diarrhea [1]. While some reports indicate the outbreak has topped 1,250 cases [3], other data suggests the number has surpassed 4,000 [1].

Disease investigators are working to identify the exact point of contamination. Public health investigators said lettuce is a possible source of the outbreak [2]. In addition to produce, authorities are investigating Taco Bell locations as part of the multistate probe [5].

The illness is not contained within Michigan. The outbreak has spread to several other U.S. states, and has been reported in Quebec, Canada [1, 2].

Investigators continue to monitor the spread of the parasite to prevent further infections. Officials said they have not yet issued a formal recall, but the focus remains on the supply chain of fresh produce and specific fast-food outlets [2, 5].

“"explosive" diarrhea”

The rapid spread of cyclosporiasis across the US-Canada border suggests a contaminated ingredient in the commercial food supply chain rather than a localized failure. Because the parasite is often linked to produce like lettuce, the investigation into both retail produce and fast-food chains like Taco Bell indicates that the source may be a large-scale distributor affecting multiple vendors.