Health department investigating after seeing more than 5x increase in cyclosporiasis cases in McHenry County
The McHenry County Department of Health is investigating a significant spike in cyclosporiasis cases, with 61 reported since late June. Officials have not yet identified a specific source for the outbreak and are advising residents to follow food safety protocols.
Why it matters
Cyclosporiasis outbreaks pose a public health risk, and identifying the source of contamination is essential to preventing further illness in the community.
File Photo | Photo: Jeremy Bronson (Wikimedia Commons/Creative Commons) The health department issued a warning as they investigate a more than five times increase in cyclosporiasis cases in McHenry County recently, with no identifiable source so far.
The McHenry County Department of Health said Friday it is investigating an increase in reported cases of cyclosporiasis in McHenry County.
The health department has identified 61 cases of cyclosporiasis since June 25, more than five times the number of cases reported during the same timeframe in 2025.
The investigation remains active and the number of reported cases may continue to change.
Symptoms of cyclosporiasis typically begin about a week after exposure and commonly include watery diarrhea, loss of appetite, weight loss, stomach cramps or bloating, nausea, fatigue and low-grade fever.
Symptoms may last for several weeks or longer without treatment, with periods of improvement followed by recurrence.
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