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Published August 06, 2013, 09:48 PM

ND West Nile cases reported in Cass, Grand Forks, Richland, Stutsman counties

GRAND FORKS – West Nile virus has infected a person in Grand Forks County, one of six such cases throughout the state, a state Department of Health official said Tuesday.

By: Tu-Uyen Tran, Forum News Service, INFORUM

GRAND FORKS – West Nile virus has infected a person in Grand Forks County, one of six such cases throughout the state, a state Department of Health official said Tuesday.

Alicia Lepp, the state’s surveillance epidemiologist, said that so far, Cass, Grant and Stutsman counties each have one case and Richland County has two.

Until Tuesday, there had only been one human case reported by the state.

Grand Forks County Public Health officials, who learned of the news Tuesday, said they won’t make changes to their mosquito eradication efforts because they’ve been operating as if such a case already existed.

Despite the reported infection, conditions in Grand Forks County have become less likely to harbor culex tarsalis, the mosquito species that carries the virus, according to Todd Hanson, head of the county’s mosquito eradication program. The county has been spraying intensively and mosquito numbers are down. The daily trap count Tuesday was four compared to 104 at its peak on June 12.

The weather has also been cooler, impeding culex activities. Hanson said they’re more active when daytime temperatures are in the 80s and 90s.

While 70 to 80 percent of those infected with West Nile virus develop no symptoms, it can cause a fever in most others and, in about 1 percent, it can harm the brain and lead to death. Among those who experience a fever, some can feel fatigued for months or longer.

Detection

Before the state reports that a person has West Nile disease, Lepp said it must confirm the infection happened recently or the previous summer.

Antibodies that are part of the body’s immune response indicate to researchers that the virus has been in the body at some point but not precisely when.

So, researchers will typically follow up a positive blood test with interviews of the patient’s doctor and the patient himself to see if symptoms are consistent with the West Nile disease, rather than, say, another kind of fever.

Assuming it’s a current infection, the Department of Health then reports the patient’s location to the local public health agency so officials there can focus their mosquito eradication efforts, if needed.

The department does not reveal such locations to the general public. Lepp said she can’t even identify the city where the patient lives.

Surveillance

At Grand Forks Public Health, news of the recent human case apparently didn’t cause much of a stir, though.

Public Health Director Don Shields said the county is one of a few in the state with a surveillance program to track the presence of West Nile virus and the culex mosquito. The first bird confirmed to have died of the virus about three weeks ago already indicated the virus’ presence here.

Tracking the birds and culex caught in mosquito traps throughout the county helps the department zero in on problem areas, Hanson said, but by the time the first dead bird showed up, the virus was already present in culex mosquitoes throughout the county.

Birds usually get the virus first, he said, because culex favors their blood and not humans’.

Still, they like our blood, too, and Shields advises those going outdoors to cover up and use bug spray that has the chemical deet in it.

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