While health officials are optimistic the West Nile virus won't reach Alaska this year, they are taking precautions and planning for testing as the mosquitos start buzzing again.
"It has a lower likelihood of coming up here, but we're going to be looking at it just to make sure," said Louisa Castrodale, an epidemiologist with the Department of Health and Social Service's Division of Public Health.
West Nile virus is a mosquito-borne illness that can cause encephalitis, or inflammation of the brain. Mosquitos become infected by biting affected birds, horses or people, and transmit the disease by biting again. The virus affects some other mammals as well, according to the federal Centers for Disease Control.
Most people infected with the virus exhibit no symptoms, or just mild flu symptoms.
The virus has been common in Africa, Eastern Europe, West Asia and the Middle East. It was first detected in the United States in 1999 and spread quickly, from four East Coast states that year to 28 states and the District of Columbia in 2001. Last year, it reached all but six states - Alaska, Hawaii, Oregon, Utah, Nevada and Arizona. The virus was detected in animals in all of the affected states, and in people in all but New Hampshire, New Mexico, Idaho and Washington. In Canada, the virus first surfaced in the east in 2001 and spread as far west as Saskatchewan last year.
For the virus to spread to Alaska, a bird would have to become infected in the Lower 48 or Canada and then migrate to the state before dying or successfully fighting off the virus, said Dr. Bob Gerlach, the state veterinarian.
"That would be hard because, depending on how rapidly the virus would affect the bird, it might not even make it to the state," Gerlach said.
Even so, the health department is planning to test birds and people for the disease this year.
Castrodale said the agency is asking health providers to inform it when patients are hospitalized with certain illnesses, including viral encephalitis and acute meningoencephalitis, both of which can result from the West Nile virus. The health department would conduct further tests to determine whether the patients had contracted West Nile.
The department also is asking people to call its offices or a local wildlife authority if they spot certain dead birds, including ravens, crows, magpies, jays, owls, eagles and falcons. Those birds are particularly susceptible to the virus and their infection is a good indicator of its presence, Gerlach said.
Castrodale cautioned people not to touch the dead birds, and said the health department will take care of testing and removal if it deems that to be necessary. Otherwise, officials will instruct people on how to dispose of the bird.
So far, the health department has no plans to test mosquitos for the virus. More information was scheduled to be posted today on the public health division's epidemiology Web site at www.epi.hss.state.ak.us/default.asp.