Minnesota's first human case of West Nile virus this season was reported Thursday. State health officials said the man, from Murray County, became ill with West Nile fever this month and is recovering.
Health officials are urging Minnesotans to protect themselves from mosquitoes by routinely using repellents and taking other precautions against mosquito bites.
This time of year is a high-risk season for West Nile virus, said David Neitzel, a state Health Department epidemiologist specializing in diseases carried by mosquitoes.
"The species of mosquito that transmits the virus to humans is most abundant in July and August," Neitzel said in a news release. "Mosquito repellents used during outdoor activities at dusk and dawn can prevent this potentially severe disease."
About one out of 150 people bitten by a West Nile virus-infected mosquito will develop central nervous system disease (encephalitis or meningitis). About 10 percent of people with this severe form of infection die from their illness, and survivors can suffer from long-term nervous system problems.
Most people bitten by infected mosquitoes develop West Nile fever, the less severe form of disease, or fight off the virus without any symptoms.
Illness from West Nile virus can occur in residents throughout Minnesota and among all age groups. However, the risk is greatest in western and central counties, which typically have the greatest number of Culex tarsalis mosquitoes, the primary mosquito carrier of the virus in Minnesota.
Elderly people or people with weakened immune systems face the highest risk of developing more severe or even fatal illness from a West Nile virus infection.
“They need to be especially diligent about protecting themselves from mosquitoes,” Neitzel said.
Besides using repellents, other important steps to prevent mosquito bites and potential illness from the virus include minimizing outdoor activities at dusk and dawn, as this is prime feeding time for West Nile virus-carrying mosquitoes.