The first case of West Nile virus has surfaced in Minnesota, infecting a man in the southwestern part of the state, the Minnesota Department of Health said Thursday.
The virus is potentially life-threatening, and the public is urged to regularly use mosquito repellents and to take other precautions against mosquito bites, according to health officials.
A man in Murray County became ill with the virus this month and is recovering, the Health Department reported.
David Neitzel, a Health Department expert in this area, said Minnesota is entering its high season for cases of West Nile virus. "The species of mosquito that transmits the virus to humans is most abundant in July and August," Neitzel said. "Mosquito repellents used during outdoor activities at dusk and dawn can prevent this potentially severe disease."
About one out of 150 people bitten by an infected mosquito will develop central nervous system ailments such as encephalitis or meningitis. About 10 percent of people with a severe form of infection die from the illness; survivors can suffer long-term nervous system problems.
However, most people bitten by infected mosquitoes develop West Nile fever, the less severe form of disease, or fight off the virus without symptoms.
Symptoms that do surface usually begin three to 15 days after a bite and can include headache, high fever, rash, muscle weakness, stiff neck, disorientation, convulsions, paralysis and coma.
The type of mosquito that carries the virus prefers open agricultural areas of central and western Minnesota and Great Plains states. While the majority of Minnesota cases have occurred in agricultural areas, cases are possible anywhere in the state.
Since the virus was first detected in Minnesota in 2002, 535 cases have been reported to the Health Department; 16 were fatal.
Last year saw a surge in the West Nile virus, with 70 confirmed cases in the state, making it the first time the number of cases had hit double digits since 2008, when 10 were reported. There were only two cases in 2011.
One of the 2012 cases proved fatal, claiming the life of a woman in Stevens County.
Experts said a possible reason for the sharp increase was that the early spring resulted in a much-longer-than-normal bug season.