"People should assume that mosquitoes infected with West Nile Virus are in their community," says Ashley Rossi Lovell, a U.S. Department of Agriculture scientist. "The

risk from mosquito bites will probably continue until a good freeze in late fall kills mosquitoes. Because WNV is widespread, the Alabama Department of Public Health (ADPH) has issued a public health alert for all Alabama counties."

Lovell is coordinating surveillance of the disease in mosquitoes and birds in Alabama on behalf of ADPH.

The most recent person stricken with the disease is from Tuscaloosa County. Tests are pending on a fifth probable case in Montgomery County. The first confirmed WNV infection was earlier this month in a 71-year-old Dale County resident. Since then a 47-year-old Houston County resident and a 79-year-old Dale County resident have been diagnosed with WNV.

Lovell says the disease has been identified in 43 of Alabama's 67 counties this year. This far exceeds the level of virus activity reported in 2001, when 59 positive birds in 13 counties were detected, and none earlier than the end of August.

In 2001, Alabama experienced two human cases of West Nile virus infection, including one fatal case.

All residents should limit their exposure to mosquitoes, says one ADPH doctor.

"This should serve as a motivator to use precautions to avoid mosquito bites," says

Dr. Charles Woernle, assistant state health officer for disease control and prevention.

"It may be a difficult behavior change for some," says Woernle. "People just are not in the habit of protecting themselves against mosquito bites around their homes. In many people's minds, it is something you do when you go camping or go to the beach."

Woernle stresses that it is important to reduce mosquito bites by limiting exposure to the insects as well as using insect repellents.

WNV can infect humans, horses and wildlife. In people, it can cause West Nile encephalitis, a potentially deadly inflammation of the brain. However, some people who are infected may never know it, and others may only experience mild flulike symptoms or headaches. As with many diseases, the elderly and those individuals with compromised immune systems appear to be at the greatest risk.

WNV and other mosquito-borne viruses such as Eastern equine encephalitis are transmitted from bird to mosquito to bird. Occasionally, the same mosquitoes will take blood from mammals, including humans and horses. Mosquitoes pick up the virus by feeding on the blood of infected birds. The disease cannot be spread from person to person or from animals to people.

Xing Ping Hu, an entomologist with the Alabama Cooperative Extension System, says the most effective mosquito repellents contain the active ingredient, DEET.

"DEET's most significant benefit is its ability to repel potentially disease-carrying insects and ticks," says Hu. "But it is extremely important that people use the product as directed on the label."

She offers the following guidelines for safe, effective use of DEET-containing insect repellents.

• Read and follow all directions and precautions on the product label.

• Do not apply over cuts, wounds or irritated skin.

• Do not apply to hands or near eyes and mouth of young children.

• Do not allow young children to apply this product.

• Use just enough repellent to cover exposed skin and/or clothing.

• Do not use under clothing.

• Avoid over-application of this product.

• After returning indoors, wash treated skin with soap and water.

• Wash treated clothing before wearing it again.

• Do not spray in enclosed areas.

• To apply to face, spray on hands first and then rub on face. Do not spray directly onto face.

Woernle adds that only repellents containing concentrations of 10 percent DEET should beused on children.

(Source: Ashley Rossi Lovell, USDA Scientist, 334-844-9244)