Encephalitis: Viral - Prevention

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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 (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. You should never handle a dead bird with bare hands.

Review Date: 01/18/2007
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital