Encephalitis: Viral - Prevention

All baits should be designed to attract the female mosquito, which is the primary transmitter of the viruses. However, different baits may be more or less effective. Some may even attract one species and not others. For example, a comparative study of three traps that used similar attractants found, that after 20 hours, the Magnet Liberty and Mosquito Trap MK01 attracted 75 percent of mosquitoes in a single area, while the Sonic Web had attracted only 25 precent. However, all three traps tended to attract twice as many Aedes mosquitoes (which carry La Cross and Eastern Equine encephalitis) as the Culex (which transmits West Nile and St. Louis Encephalitis).

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Bug Zappers.Insect light traps (commonly called bug zappers), which attract and electrocute insects, may actually spread viruses and bacteria that are on the insects. They are also not very effective for killing female mosquitoes.

Encouraging Natural Defenders. Some attempts have been made to control mosquito populations with natural defenders, including building bat and bird houses to attract natural predators or growing certain insect-repellent plants.

Citronella Candles. Burning citronella candles reduces the likelihood of bites. (Indeed, burning any candle helps to some extent, perhaps because the generation of carbon dioxide diverts mosquitoes toward the flame.)

Other Preventive Measures

Your home environment, personal hygiene, and what you wear can also help reduce your risk for mosquito bites.

Wear trousers and long-sleeved shirts, particularly at dusk. One survey suggested that this measure may significantly reduce the incidence of mosquito-born disease.
Sleep only in screened areas.
Air-conditioning may reduce mosquito infiltration. Where air-conditioning is not available, fans may be helpful. Mosquitoes appear to be reluctant to fly in windy air.
Don't wearperfumes.
Cover up bare skinafter dusk.
Wash your hair at least twice a week.

Public Spraying

Public health measures are the best methods for controlling mosquitoes.

Spraying. Local areas that experience outbreaks of encephalitis from mosquitoes usually have a spraying program.

Insecticides containing synthetic pyrethroids (e.g., permethrin, resmethrin, and sumithrin) are generally recommended by consumer groups as being the most effective and the least toxic to people (although they are toxic to fish and bees).
Malathion and naral--another pesticide--are organophosphates and approved for spraying mosquitoes. Malathion specifically has been widely used in a number of areas. Organophosphates, however, can have toxic effects on the nervous system. Some people, for example, have reported being sick after exposure to Malathion. In addition, there is a risk that mosquitoes will develop resistance to it.

Report Dead Birds. Dead birds may be indicators that the West Nile has reached a specific region. People who spot any should report them to local public health authorities; dead birds should never be handled with bare hands.