West Nile virus found in Nevada

Tuesday, July 20, 2004 | 11:05 a.m.

A dead crow found in a Carson City back yard is the first hard evidence of the West Nile virus in Nevada, state officials said Monday.

A senior specialist picked up the dead bird from a woman's home on Thursday. A swab taken from the bird Friday tested positive for the virus later that evening, Carson City environmental health specialist Mike Faisy said.

No cases of the virus involving people have been detected yet in Nevada, Dr. Bradford Lee, the state health officer, said Monday.

People can take preventive measures, such as using insect repellent containing DEET, wearing long sleeves and pants when outdoors, making sure window screens are intact and draining any standing water around homes and businesses, he said.

Mosquito trapping and surveillance of dead and sick birds will be "significantly enhanced" over the next few weeks, perhaps lasting for months, state Veterinarian David Thain said.

West Nile virus is spread when mosquitos bite infected animals or birds and then bite other animals.

Washoe County health officials installed 20 mosquito traps around the immediate area where the crow was found. Only one species of mosquito, Culex tarsalis, was found, indicating a very low risk of widespread infection in mosquitos.

Thain urged people to advise health officials if they see any dead or sick birds, adding that reporting dead and sick birds is an important part of the overall surveillance effort.

"The dead crow was reported to the Carson City Health Department by an alert citizens who knew we were looking for dead birds to test," Thain said.

If more than one bird is infected, it could indicate a local population infected with West Nile virus.

Horse owners in Nevada should vaccinate their horses against the West Nile virus as soon as possible, Thain said. California reported one case of equine West Nile virus last year but there have been 26 cases reported this year. Eleven of those horses have died, he said.

Since the virus was first detected in 1999 in New York, Nevada has been preparing for its arrival. The Nevada West Nile Virus Working Group was formed last year to monitor the situation.

Last year Colorado was the state hardest hit by the virus, with 2,947 people who were sickened and 61 who died, the federal Centers for Disease Control and Prevention in Atlanta said.

Two Nevadans were infected with West Nile last year, but both contracted the disease while they were out of state, health officials said.

Nationwide 9,858 people were diagnosed with health problems caused by the virus in 2003, and 262 died. The virus can act like a mild infection, called West Valley fever, or it can be more dangerous to those 50 years and older, the CDC said.