Researchers Immunize Mice Against West Nile

NEW HAVEN, Conn-Researchers at Yale University have successfully immunized mice against West Nile virus.

The virus has emerged in North America and Europe in the past few years; however, it has been a serious health concern in the Mideast since the 1950s. Originally isolated in a febrile adult woman in the West Nile District of Uganda in 1937, the virus causes severe human meningoencephalitis.

An equine strain of the disease was first noted in Egypt and France in the 1960s. Researchers believe it was brought to the US by zoo animals.

West Nile virus is contracted by an infected mosquito bite. The mosquito becomes infected after feeding off of an infected bird. There is no human-to-human or bird-to-human transmission reported. Although the spread of the disease has been rapid along the eastern coast, officials at the Centers for Disease Control and Prevention (CDC) think the virus will spread slowly.

Seventeen human cases of West Nile were reported in 2000, all in New York City and New Jersey. The virus can cause encephalitis, a brain inflammation. But it's unknown how many healthy people shrugged off a milder case of West Nile, which can feel like the flu, without seeking medical attention. Most confirmed cases tend to be among patients with weaker immune systems, such as the elderly and young children.

Experts now know the culprit behind the virus-the Culex mosquito. They knew the disease was mosquito-borne, but they have now determined the specific mosquito that carries the virus. With this information, they are further informing the public to protect themselves from mosquito bites.

People are being urged to limit breeding grounds for the bugs by eliminating any standing water in gutters, old tires, wadding pools, outside containers, and pails. Health officials are also suggesting people wear long sleeves and pants outside, especially at dawn and dusk when mosquitoes are most prevalent. Wearing a bug repellent containing the chemical DEET.

The four major symptoms of the disease are fever, an altered mental state, spinal fluid with elevated levels or protein, and muscle weakness.

The Yale researchers reported in the November issue of the Journal of Immunology that they successfully genetically engineered a vaccine from a protein found in the virus. After injecting this into mice, they found their mutation was efficacious.

Information from www.latimes.com, previous Infection Control Today reports.