WEST NILE VIRUS DETECTED IN LANCASTER OFFICIALS SAY RISK OF INFECTION IS LOW.

Byline: Charles F. Bostwick Staff Writer

LANCASTER - West Nile virus has been detected in central Lancaster, mosquito-control officials said Tuesday.

The virus was found in a chicken living in a flock kept near Division Street by the Antelope Valley Mosquito and Vector Control District to detect mosquito-borne diseases.

``We will be increasing our surveillance in that area, to see which mosquito species is responsible for transmitting the virus,'' said Karen Mellor, an entomologist for the mosquito-control district.

Potentially fatal to humans - especially chronically ill and elderly people - and to horses, West Nile virus is spread by mosquitoes that bite infected birds and then pass it on to people or other animals.

Outbreaks commonly strike in late spring and summer, as mosquitoes multiply in warming weather.

Despite the confirmation of the disease, that area has relatively few mosquitoes, Mellor said. A mosquito trap near the flock has been catching only one or two mosquitoes a week, far fewer than other local traps, she said.

Flocks of chickens are set out to detect the virus because it is not fatal to them as it is to ravens, jays and other wild birds, and because there is no chance they picked up the disease in another area, as wild birds might.

So far this spring, West Nile virus has been detected in 22 counties around California but there have been no reported human cases.

West Nile virus last year infected more than 300 Los Angeles County residents, including 190 who became ill enough to be hospitalized and 13 who died. The largest outbreak was in the San Gabriel Valley. The human case closest to the Antelope Valley occurred in Saugus.

While the Antelope Valley had no human cases last year, two horses became sick - one so seriously it was euthanized.

Earlier this spring the virus was detected in wild birds found dead in Rosamond and at Edwards Air Force Base.

Health officials say the risk of acquiring the virus is low. About 80 percent of people who become infected with the virus show no symptoms, and most of those who become ill show only mild flu-like symptoms.

In rare cases, the virus can cause encephalitis and death. People over age 50 are most at risk for severe cases of the disease. There is no specific treatment for the virus.

Dead birds are an early sign of the arrival of the virus, which is not spread by person-to-person contact - though it has been spread by breast- feeding and blood transfusions - or directly by birds.

Charles F. Bostwick, [phone]

chuck.bostwick(at)dailynews.com

AT RISK

--People at the highest risk of life-threatening disease are over age 50 or have weak immune systems from another illness.

--Most mosquitoes do not have West Nile virus.

--Eighty percent of infected people have no symptoms. People typically develop symptoms between three and 14 days after they are bitten by an infected mosquito.

--Mild symptoms include fever, headache, body aches, vomiting and sometimes swollen lymph glands or a skin rash. They pass on their own.

--Of those infected, one in 150 can develop severe symptoms or even die. Severe symptoms can include high fever, neck stiffness, tremors, muscle weakness, vision loss, numbness and paralysis. Neurological effects may be permanent.

--The best way to protect against the disease is to protect against mosquito bites.

Source: Los Angeles County Health Department, Centers for Disease Control and Prevention 

MOSQUITO TIPS

To reduce exposure to the virus, health officials suggest residents follow the precautions recommended for all mosquito-borne diseases:

--Get rid of standing water, where mosquitoes can breed. Empty all small containers at least once a week, keep pools and spas chlorinated or drained, and avoid overwatering that lets water form puddles on lawns or in gutters.

--Get mosquito-eating fish (Gambusia affinis) for free from the mosquito district if you have sources that cannot be drained, such as fish ponds and large horse troughs.

--Wear long-sleeve shirts and pants and use mosquito repellent containing DEET when outdoors during dusk and dawn.

--Keep tight-fitting screens on doors and windows to prevent mosquitoes from entering homes.

--Horse owners should make sure their horses are properly vaccinated.

--Report stagnant pools and other backyard sources to the mosquito district so technicians can treat them.

The mosquito district can be reached at [phone]. Its Web site is www.avmosquito.org. Crows and ravens that have recently died - without obvious trauma - can be reported by calling (877) WNV-BIRD. Use gloves, a shovel or an inverted trash bag to pick up any dead bird.

Source: Antelope Valley Mosquito and Vector Control District

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