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.

The illness can cause prolonged diarrhea and there is a risk of dehydration.

Individuals experiencing decreased urination, dizziness or headache after ongoing diarrhea should seek medical treatment for dehydration.

Anyone whose diarrhea persists for more than a couple of days is encouraged to contact their primary care provider or seek medical attention for evaluation, testing and appropriate treatment.

Cyclosporiasis cases are associated with the consumption of contaminated fresh produce or water.

Cyclosporiasis outbreaks historically have been linked to a variety of fresh produce items, including leafy greens such as lettuce, fresh herbs, snow peas, green onions and berries.

The McHenry County Department of Health said there is no specific source that has been identified in the current investigation, which is ongoing.

The health department said it encourages residents to follow routine food safety practices to help reduce the risk of foodborne illness.

Those include rinsing all fresh fruits and vegetables under running water and gently scrubbing or wiping produce before eating, cutting or cooking.

Safety practices also include scrubbing firm produce, such as melons and cucumbers, with a clean produce brush as well as washing and sanitizing cutting boards, utensils, containers and other food contact surfaces after preparing fresh produce.

Anyone preparing food, handling fresh produce or using the restroom should wash their hands thoroughly with soap and water.

“With no specific food source identified, consumers can reduce, but not completely eliminate, their risk by carefully washing, preparing, and storing fresh produce,” the health department said.

Cooking produce to an internal temperature of 158 degrees Fahrenheit is more effective than washing alone because it inactivates cyclospora, health officials said.

The McHenry County Department of Health said they will continue to monitor the situation and provide updates when available.