West Nile battle on again
Tracy B. Cieniewicz, Hartselle Enquirer
Mosquitoes took a larger than normal bite out of Americans last year.
All but four states-Arizona, Nevada, Oregon and Utah-confirmed cases of animals or humans infected with the West Nile virus in 2002.
According to the Centers for Disease Control and Prevention, more than 4,000 people across America have contracted the virus since it first emerged in 1999. Approximately 263 people, most of them elderly, have died as a result.
The Alabama Department of Public Health has confirmed human or animal cases of West Nile virus in each of the state's 67 counties. As of Feb. 1, 50 human cases and three deaths have been confirmed in Alabama.
Although 16 birds have tested positive for the virus, there have been no confirmed human or horse cases in Morgan County.
The USDA Wildlife Service is preparing to conduct a West Nile virus statewide surveillance project in Alabama for the fourth consecutive year. Wildlife biologist Ashley Lovell is coordinating the project.
"Right now we are taking advantage of the off season to prepare for the warmer months ahead in 2003," Lovell said.
West Nile virus causes West Nile encephalitis, an inflammation of the brain caused by virus bacteria, and is transmitted by the bite of an infected mosquito. While birds are the best indicators of the virus, Lovell said any animal a mosquito feeds upon is susceptible.
"Public awareness is key," Lovell said. "The reason we monitor West Nile virus is the same as any other disease. It alerts health departments and the public to a potential problem."
While bird and mosquito surveillance is only conducted during the months of May through November, Lovell said horse surveillance is conducted year-round.
"Several infected horses in southern parts of Alabama were confirmed in late December and early January," Lovell said. "This indicates to us that mosquitoes have the potential to be active throughout the year, despite cooler temperatures."
Dr. Gary Mullen, professor at Auburn University's Department of Entomology and Plant Pathology, agrees with Lovell that winter weather isn't necessarily a deterrent for mosquitoes.
"Year after year, mosquitoes seem to get through winter quite well," Mullen said. "When daytime highs rise to 60 degrees, as we have seen recently, mosquitoes may very well take flight."
Despite unusual highs and lows across the state this winter season, Mullen said winter weather is not a factor in determining mosquito or West Nile virus control.
"The severity of winter has little effect on the following season's mosquito population," Mullen said. "Their eggs tolerate freezing temperatures and then hatch based on warm weather and rainfall amounts in the spring."
Although freezing temps may not deter mosquitoes or the spread of West Nile, Mullen predicts that Alabama will still see fewer human and animal virus cases this year.
"When a virus first reaches a new area, evidence indicates that the number of cases drops dramatically the following year," Mullen said. "Since Alabama had its largest number of cases in 2002, it should be expected to see significantly less in 2003."