Mosquitoes spreading two viruses

"At least two different viruses are being spread by mosquitoes, so it’s especially important this year that we avoid them as much as possible," says Donald Williamson, state health officer with the Alabama Department of Public Health.

West Nile virus has been identified in 12 birds in eight Alabama counties: Baldwin, Clay, DeKalb, Macon, Marshall, Shelby, Talladega and Winston. Six of these West Nile-infected birds were identified during the first week of July.

Recently, Eastern Equine Encephalomyelitis (EEE) was confirmed in horses in Baldwin and Mobile counties, and in emus in Butler County. In addition, Georgia and Florida have confirmed EEE in at least 110 horses and 97 birds, and West Nile Virus in two horses and 60 birds.

According to John Mosely Hayes, a health department epidemiologist, "An easy way to remember what you can do to protect yourself and your loved ones from mosquito-borne diseases is to remember the five D's of prevention: dusk, dawn, dress, DEET and drain.

"Avoid being outside during dawn and dusk when mosquitoes are most active. Dress to cover your skin with protective clothing. Protect bare skin with mosquito repellent that contains DEET. And drain empty containers holding stagnant water in which mosquitoes breed."

West Nile Virus was diagnosed in 49 humans last year in Alabama. At least four died. The virus is likely to be a threat every year. EEE occurs almost every year in animals in Alabama, and epidemics in horse and emu populations happen every four to five years. The last human death from EEE in the state was in 1996. So far this year, no human cases of mosquito-borne viral disease have been confirmed in Alabama.

Avoiding mosquito bites and eliminating mosquito breeding sites will help protect individuals and the community from West Nile Virus, EEE and the other mosquito-borne viruses that occur in Alabama, says Williamson.

These viruses are maintained by transmission between birds and mosquitoes. However, sometimes the viruses are spread to humans and other animals by mosquitoes that feed on infected birds and then bite humans and other animals. People contribute to the continuing cycle of these viruses by maintaining environments — especially standing water — in which mosquitoes can lay eggs.

These mosquito-borne viruses are not spread person-to-person, animal-to-human, or animal-to-animal, notes Williamson. A person or animal usually is infected through the bite of an infected mosquito. The key to protection is avoiding mosquito bites.

Very few mosquitoes are infectious, and most people who are infected do not get sick. In some individuals, these viruses can cause a serious illness called encephalitis, which is an inflammation of the brain.

"People with encephalitis are sick enough that they will seek medical care and be hospitalized," says Williamson.

Symptoms of encephalitis may include high fever, severe headache, nausea, stiff neck, confusion, muscle weakness, paralysis, disorientation, convulsions, coma and rarely, death. The seriousness of an illness may depend on a person's health and age.

West Nile Virus affects the elderly most severely, and EEE affects the young and elderly most severely.

Mosquito control programs are being operated locally, says Williamson, and the health department is helping to protect Alabamians from mosquito-borne disease by tracking the spread of these viruses and educating individuals and communities on ways to protect themselves from mosquitoes.

"By working with a wide variety of partners — health care providers, veterinarians, the Alabama Emergency Management Agency, the Centers for Disease Control and Prevention, Alabama universities, the Alabama Department of Agriculture and Industries, and the U.S. Department of Agriculture — the health department is monitoring for virus activity in humans, horses, birds and mosquitoes, and helping establish local mosquito control programs," says Williamson.

More information about these efforts and a booklet titled, "How to start a mosquito control program in your town, Alabama," is available from the Alabama Department of Public Health.

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