Health District warns about West Nile virus

By Cara McCoy

Tuesday, March 17, 2009 | 1:45 p.m.

The Southern Nevada Health District is urging residents to help keep the mosquito population under control in an effort to stymie incidents of West Nile virus.

Stagnant water sources -- even those as small as a cup of water -- are the optimal breeding source for mosquitoes, health district spokeswoman Stephanie Bethel said. Swimming pools, ornamental pools and other areas around homes should be maintained to eliminate standing water, she said.

Residents are asked report "green" swimming pools or stagnant water sources to the health district. Last year, the health district responded to more than 2,850 green pool complaints, most of which were abandoned homes, Bethel said.

Health district specialists routinely survey and treat known breeding sources for mosquitoes. The insects are trapped for identification and testing for West Nile virus, Western equine encephalitis and St. Louis encephalitis, she said.

West Nile virus first appeared in Nevada in 2003. Last year, 16 human cases of West Nile virus were reported in Nevada, the health district said. Nationwide, 1,338 cases were reported and 43 people died, according to Centers for Disease Control and Prevention records.

The disease first appeared in the U.S. in the late 1990s in New York and has since spread across the country, the health district said.

The disease is spread through the bite of infected mosquitoes, which acquire the disease by feeding on infected birds. West Nile virus can't be spread by person-to-person or casual contact.

While there are 17 species of mosquitoes in Southern Nevada, only a few species can carry the disease, the health district said.

To report stagnant water or green pools, visit www.SouthernNevadaHealthDistrict.org or call the mosquito control hotline at 759-1220.

Stagnant water can be treated with larvicide or mosquito fish.

The health district recommends the following strategies to eliminate standing water:

Swimming pools:

• Maintain water circulation and chemical concentrations
• Remove rain water from pool covers
• Stock “out-of-order” pools with mosquito fish
• Change water weekly in wading pools
• Store wading pools indoors when not in use
• Store wading pools upright

Ornamental pools

• Stock with fish
• Remove leaves and thin out plants
• Keep water levels up and keep water clean
• Screen the inlet of the recirculation pump
• If not in use, break holes in the bottom and refill with sand

Standing water sources

• Repair leaky plumbing under and around the house
• Prevent seepage from garden irrigation
• Divert storm water away from foundations
• Drain the air conditioner outlet
• Clean rain gutters
• Remove and dispose of all unused containers that collect water
• Change water weekly in rooting plant containers
• Usable containers should be stacked upside down