The Mosquito Abatement District of St. Tammany and the Louisiana Department of Health and Hospitals said Friday that the first case of West Nile virus in the state for 2009 has been confirmed in Covington.

Mosquito Abatement District Director Chuck Palmisano said that there has also been one case of a horse contracting the disease, but the horse has fully recovered.

West Nile virus has slowly been making its way across the country over the past several years. It is spread by mosquito bites, primarily the southern house mosquito, or Culex quinquefasciatus. However, there is no real need for alarm or panic, according to LDHH spokesperson Jolie Adams. She said that of all the people in Louisiana that contract the disease, 90 percent are asymptomatic, that is show no symptoms. In 2008, there were 58 confirmed cases of West Nile in the state. Of those, 30 were asymptomatic, 9 patients got symptoms including fever, and 19 actually got the form of West Nile encephalitis, which is very serious and dangerous.

“It’s only a handful that get the serious form of the disease,” Adams said.

Even so, Palmisano said his department is not taking any chances. They check out various areas around the parish for the presence of the southern house mosquito. There are 2,449 pools of water that are checked out every week. Palmisano said that so far 12 locations have tested positive for West Nile virus and those are all in the western end of the parish.

Palmisano said the southern house mosquito has a breeding cycle of 7 to 10 days, and mostly breed in roadside drainage ditches with high organic content. So every five days, his workers treat parish ditches with a bacterial spore called Bti. The mosquito larvae in the water eat this spore. Once ingested, the spore releases a toxin that is poisonous to the mosquito. He said the Bti treatment is working, because testing has shown that larval counts in the ditches has decreased.

Of course, the Mosquito Abatement District also continues to spray the parish with trucks and airplanes. He said the Covington area has been sprayed several times this month.

Besides humans, the southern house mosquito can spread West Nile to horses. Palmisano urges anyone who owns horses to have them all vaccinated against the disease. He said the West Nile vaccine for horses is very effective.

For humans, the best defense against the virus is to keep mosquitoes from biting. Both Palmisano and Adams urge parish residents to be proactive and help to keep the mosquito population down.

Residents should use insect repellent containing 20 to 30 percent DEET for adults and no more than 10 percent for children. People should wear long-sleeved shirts, long pants when outdoors, and try to avoid being outdoors in the early morning or early evening, because this is when the southern house mosquito usually swarms. If you go outdoors for a long time, avoid using perfumes or cologne because these attract the mosquitoes.

Above all, residents should make sure there are no standing pools of water where the mosquito can lay their eggs and breed. Empty out flowerpots, cans or other containers that are outside. Drill holes in the bottom of containers so water does not accumulate. Turn wheelbarrows, garbage cans, wading pools and buckets upside down when not in use to avoid collecting water.

Palmisano said checking for pools of water is especially important, because of the recent rainfall. He said the increase in rain fills up the marshes, which become a breeding ground, and his workers are busy going out spraying marshlands and the woods.