The McHenry County Department of Health announced Friday that they have identified the first human case of West Nile virus in McHenry County in 2024.
The McHenry County Department of Health (MCDH) said the county’s first human West Nile virus case of the 2024 surveillance season was identified.
McHenry County has reported two other human West Nile virus cases in the past five years. One was in July 2022 and another was in September 2023.
As of Friday, eight mosquito batches and an owl have tested positive for West Nile virus in the county.
The Illinois Department of Public Health (IDPH) reports there have been 19 human cases of West Nile virus in 2024 in the state with one death.
The death occurred in a Lake County resident who was in their 80s and first experienced an onset of symptoms of West Nile virus in mid-August before dying later in the month.
West Nile virus surveillance is conducted from May to October.
The virus can be transmitted to humans through the bite of an infected Culex species mosquito approximately two to 14 days later.
The MCDH said illness from West Nile virus is usually mild and includes fever, vomiting, headache and body aches but serious illnesses, such as encephalitis and meningitis and death, are possible.
Those 60 years of age or older or who have serious underlying health conditions are at higher risk for developing severe symptoms.
The MCDH said mosquitoes typically breed in stagnant water high like abandoned swimming pools, bird baths, buckets, clogged gutters and rimless tires.
“The first and best defense against mosquito-borne illness is to eliminate potential mosquito breeding sites on your property by emptying standing water from containers around the house and making sure doors and windows have tight-fitting screens,” the MCDH said.
Health officials also recommend residents use insect repellents approved by the EPA.