Salmonella cases back to ‘baseline’ in the county after spike in June

Salmonella cases in McHenry County are back to “baseline” after July cases were tallied, following a spike in June.

The McHenry County Department of Health had reported a “threefold” increase in cases of the gastrointestinal illness during the month of June, prompting officials to urge the public to be cautious and take preventive measures.

The county reported 19 salmonella cases in June, but cases returned to “baseline” levels in July with two, department spokesperson Nick Kubiak said. Three salmonella cases were reported in May, according to health department provisional data.

The health department previously reported 10 cases of salmonella in June.

The data for 2025 “is provisional, so it is subject to change as investigations evolve and new reports are received,” Kubiak said.

Gastrointestinal illness can be more common in the warmer months, health department officials said earlier this summer.

The health department said in June people can contract diseases like salmonella, campylobacteriosis and cyclosporiasis through consuming or handling contaminated or undercooked food, drinking contaminated water or coming into contact with infected animals or animal waste.

Gastrointestinal illness as a whole was down in the county in July, according to health department data.

The department reported two cases of salmonella in July and five cases of campylobacteriosis. Those were the only gastrointestinal illnesses the health department reported during the month, but health officials track other gastrointestinal illnesses including E. coli, cholera, typhoid fever and paratyphoid fever and vibriosis.

The department reported 32 cases of gastrointestinal illness in June, including the 19 salmonella cases and 11 campylobacteriosis cases. The other two were an E. coli case and a shigellosis case. In May, the county reported 11 total gastrointestinal illness cases.

While high bacteria levels in the water have prompted beach closures in McHenry County beaches this summer, including Crystal Lake’s Main Beach, no cases of E. coli were reported in the county in July.