Mosquito fighters gear up to swat the pests

Sunday, June 16, 2002

ALBANY, Ga. -- Humans vs. mosquitoes: The South's annual war against the bloodsucking insects is usually just a battle to prevent the nasty, itchy bites that the pests inflict on almost everyone who goes outside during warm weather.

But this year, after the region's first deaths due to mosquito-borne West Nile Virus, the humans are pulling out the big guns.

"Studies have shown West Nile is here to stay for a while," says Donell Mathis, the chief mosquito fighter in southwest Georgia's Dougherty County. "We're going to have to do everything we can to control the mosquito population."

Mathis and two technicians are putting out mosquito monitoring traps for the first time this spring and will attend classes to help them identify the 14 mosquito species that are known to carry the virus.

Wealth of weapons

The technicians use chemical sprays, known as adulticides, to kill adult mosquitos, and began spraying in mid-April. They have other weapons, known as larvicides, for fighting immature mosquitos in standing water. Larvicides include chemicals, growth-disrupting hormones and alcohol solutions that suffocate the pests.

West Nile Virus has sickened 149 humans and killed 18 since its discovery in the New York City area in 1999, according to the Centers for Disease Control. There were 66 cases and nine deaths last year.

University of Georgia entomologist Elmer Gray, who attended a national West Nile conference sponsored by the CDC, says the virus has made mosquito control more important than ever.

"The rapid and widespread occurrence of the West Nile Virus this past summer is one of the most interesting and unique occurrences in the entomological field in a long time," says Gray, an Extension Service specialist who presents talks and training sessions on mosquito control throughout Georgia.

CDC officials say West Nile could be circulating through some parts of the South throughout the year, especially in the Gulf Coast States, which are a haven for mosquitos.

One of the best weapons against mosquitos may be the South's four-year drought, which will prevent some mosquitos from finding standing water in which to lay their eggs, Gray says.

However, that can change rapidly with rainfall.

In the heat of the summer, a mosquito can develop from egg to adult in 4 to 5 days, but in the spring, when temperatures are milder, the transformation may take 10 days to two weeks, he says.

Health officials have been alarmed by the rapid spread of the virus from Ontario, Canada, to the Florida Keys in three years. It is transmitted to humans, birds, horses and other animals by mosquitoes.

West Nile causes a flulike illness. But for older people, or those with weak immune systems, it can cause deadly encephalitis, an inflammation of the brain.

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