West Nile Virus and Alaska

Alaska state and federal agencies are preparing for the arrival of an unwanted visitor, the West Nile Virus.

The West Nile Virus, spread to the New York metropolitan area from overseas sometime in 1999, has worked its way west by its two main carriers, mosquitoes and birds. The virus, sometimes but rarely fatal in humans, has killed thousands of wild birds and horses. In 2002, the U.S. Centers for Disease Control and Prevention charted the virus’ spread to 16 new states, including Washington. The states with no reported cases as of late 2002 were Oregon, Nevada, Utah, Arizona, Hawaii, and Alaska.

With the rapid spread of the virus the past two years, Alaska agencies are working now to monitor any possible cases in Alaska. Kimberlee Beckmen is a wildlife veterinarian with the Alaska Department of Fish and Game in Fairbanks involved in a surveillance plan for the virus that includes the U.S. Fish and Wildlife Service, the U.S. Geological Survey, the Alaska Department of Health and Social Services, and the University of Alaska Fairbanks. Beckmen is coordinating the testing of Alaska wild birds.

“We haven’t seen the virus in Alaska yet,” Beckmen said.

Chances of the virus taking hold in Alaska are slim, according to Beckmen and Jim Kruse, an insect expert at the University of Alaska Museum. Birds carry the virus, and mosquitoes spread the virus by biting infected birds and injecting it into other birds, people or horses. Alaska has natural limitations for the spread of the virus.

A mosquito has to bite an infected bird during a 2-to-4 day window when there is enough virus in the bird’s bloodstream, then the virus has to multiply within the mosquito, Beckmen said. The mosquito could then infect people, birds and horses by biting them, but Alaska’s remote nature lessens the danger to people.

“We could get fairly high numbers of West Nile Virus in birds and mosquitoes and only get a few cases of people being infected here and there,” Kruse said.

Researchers have found that the virus is much harder on wild birds than it is people or horses.

“More people will get sick and die from the flu than West Nile Virus,” Beckmen said. “About 1 in 1,000 people that get infected die.”

The virus has killed thousands of North American birds since 1999, most of them in the crow family. Ravens, the largest members of the crow family, will perhaps be the indicator species in Alaska if the virus establishes itself up here. Other birds killed by the disease include the gray jay, magpie, and many types of raptors.

“Birds that show symptoms have tremors, can’t fly, and don’t hold their wings normally,” Beckmen said. “Because of this, they are much more likely to get hit by a car or run into a window than a healthy bird.”

The Alaska scientists agree that it’s a long shot for the West Nile Virus to establish itself in Alaska. The disease has not made it to higher latitudes of Europe and the two mosquito species that have transmitted the virus most often in the Lower 48 don’t live in Alaska.

“Until we start getting dead birds up here, there’s no reason to worry,” Kruse said.