West Nile virus: Utah keeps an eye out

KAYSVILLE — There's a group of nasty, determined females out there who want nothing more than to suck a man's (or woman's) blood.

Itchy mosquito bites are bad enough, but this year they could be dangerous if the dreaded West Nile virus comes to Utah. Male mosquitoes, which lack the ability to bite, won't transmit the disease. Only females, with their need for a blood meal to develop eggs, cause misery to humans and animals. Most people who live some distance from mosquito breeding grounds have probably never seen a male mosquito, experts say.

Mosquito-borne diseases kill more than a million people each year worldwide. Such diseases include malaria, yellow fever, West Nile virus, St. Louis encephalitis, western equine encephalitis and dog heartworm disease.

No new West Nile cases have been reported in any state this season, but Gary Hatch, manager of the Davis County Mosquito Abatement District, expects the virus to show up sometime this summer. His employees are fighting in defensive mode until then by spraying marshlands on the edge of the Great Salt Lake, using trucks, ATVs, handsprayers and an airplane.

The district also has given thousands of tiny mosquito-eating fish to homeowners to put in their ornamental ponds.

The elderly are especially hit hard by West Nile, Hatch said. Young children also are susceptible.

Standing guard against the threat of the mosquito-borne disease are several hundred chickens in flocks throughout northern Utah and in Moab. The chickens, likely to be among the first to be bitten by infected mosquitoes, are in sentinel flocks whose blood is regularly checked for disease. Blood is taken each week from the chickens and sent to a state lab to see if antibodies to the West Nile, St. Louis encephalitis and western equine encephalitis viruses are present.

The district also collects 50 adult mosquitoes weekly, grinds them up in a test tube and sends the tube to a lab to see if the virus is in the mosquitoes.

Many counties in the state have mosquito abatement districts or programs administered by health departments. Salt Lake County has three districts: one in Salt Lake City, one in Magna and one in the south part of the county.

Mosquito-borne diseases start with infected birds who carry viruses. Disease spreads when a mosquito bites a bird while seeking a blood meal, transmitting the virus to the insect. After 10-14 days, the virus can be transmitted to another bird, animal or human bitten by the mosquito.