Minnesota reports first West Nile case this year

This year's first human case of West Nile virus in Minnesota was reported Thursday by the state Health Department.

An adult woman in Wadena County has been hospitalized for encephalitis after testing positive for the disease.

In late June, she became ill with a high fever and severe headache. Her condition is slowly improving, the department said.

The state's first human case in 2004 was reported Aug. 3.

Dave Neitzel, an insect-borne disease specialist for the department, said several factors contributed to a West Nile case occurring earlier than previous years.

"We had a lot more rain than normal," he said. "Add heat to the equation and it speeds up development time."

Human cases usually peak in August, Neitzel said.

The discovery of the first case, he said, is a reminder to take precautions when mosquitoes are feeding - mainly around dusk and dawn. Mosquito repellents that contain DEET or Picaridin are recommended.

Brady Scribner, an environmental health practitioner for Fargo Cass Public Heath, said limiting exposure during peak feeding times is important. He said if possible, people should wear long sleeves and pants.

Property maintenance can also help reduce the risk of mosquito breeding. Scribner said eliminating standing water and keeping weeds trimmed will curb the rising mosquito population.

According to the North Dakota Department of Health Web site, 198 people have been tested for the disease nationally since June 1. No human cases have been reported in North Dakota.

For the Fargo area, a jump in mosquito trap numbers earlier this week has prompted another round of aerial spraying.

Weather permitting, spraying is planned for 7:30 tonight, said Cass County Vector Control Director Angela Balint.

Mosquitoes that carry the virus in Minnesota and North Dakota, Culex tarsalis, usually make up 5 percent to 10 percent of trap counts, Neitzel said. Other species of mosquitoes in the area don't pose a threat.

Aerial spraying, Balint said, is a way to keep the number of adult mosquitoes down.

"The older that you let them get, the more likely they are to be carrying (West Nile)," she said.

Trapped mosquitoes in Cass County are tested for the disease. None have tested positive, Balint said.

A few mosquito eggs could receive the disease from their mother, Neitzel said, however most need to feed on an infected bird to be a carrier.

In Minnesota one infected bird was identified in Dakota County. Horses in Clay, Chippewa, Pipestone and Murray counties also have West Nile, according to statistics from the Department of Health Web site.

A Burleigh County horse is the sole case of West Nile in North Dakota this year.

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Barbara Raus at (701) 235-7311