/Southern Nevada Health District Detects West Nile Virus in Mosquitoes Prevention is Urged

Southern Nevada Health District detects West Nile virus in mosquitoes Prevention is urged

July 28, 2008

LAS VEGAS – The Southern Nevada Health District’s vector control program has detected West Nile virus in a cluster of mosquitoes in the 89122 zip code. In 2007, Nevada had a total of 12 human cases of West Nile virus, three of whom were residents of Clark County. For more information or to report mosquito activity, “green” swimming pools or stagnant water sources, visit the health district website at www.SouthernNevadaHealthDistrict.org or call the mosquito control hotline, (702) 759-1220.

The health district’s environmental health specialists routinely survey and treat known breeding sources for mosquitoes and trap them for identification. In addition, they are tested for West Nile virus, Western equine encephalitis and St. Louis encephalitis. West Nile virus is spread through the bite of infected mosquitoes, which acquire the virus by feeding on infected birds. The illness is not spread person to person.

The health district strongly stresses the need for individual protective actions to avoid mosquito bites:

  • Apply an insect repellent containing DEET (N, N-diethyl-meta-toluamide) according to manufacturer’s directions. Repellents containing picaridin and oil of lemon eucalyptus also have some efficacy. However, DEET is the best-studied and most-effective repellant available.
  • Wear pants and long-sleeved shirts, when outdoors.
  • Avoid spending time outside when mosquitoes are most active, notably at dusk (the first two hours after sunset) and dawn.

Stagnant water sources are the optimal breeding source for mosquitoes. Southern Nevadans are urged to eliminate areas of standing water, including bird baths, un-maintained swimming pools and sprinkler runoff, which all support mosquito breeding. There are 17 mosquito species in Southern Nevada, however, only a few are known to “feed” on humans and horses and carry disease. The health district recommends the following strategies to eliminate standing water:

Swimming pools

  • Maintain circulation of swimming pool water
  • Keep pool covers tightly sealed
  • 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
  • Avoid spraying with garden insect sprays
  • 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

West Nile virus made its first appearance in the United States in the late 1990s in New York and has since spread across the country. The disease first appeared in Nevada in 2003. In 2007, the Centers for Disease Control and Prevention recorded 3,598 human cases of West Nile virus nationwide; 121 deaths were reported.

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The Southern Nevada Health District serves as the local public health authority for Clark County, Boulder City, Henderson, Las Vegas, Mesquite and North Las Vegas. The agency safeguards the public health of the community’s residents and visitors through innovative programs, regulations, and initiatives focused on protecting and promoting their health and well-being. More information about the Health District, its programs, services, and the regulatory oversight it provides is available at www.SNHD.info.