Southern Nevada Health District surveillance detects

West Nile virus in mosquitoes Prevention is urged


8 August, 2007

Las Vegas – The Southern Nevada Health District today announced that its surveillance program has detected West Nile virus in a cluster of mosquitoes in the county. The health district announced the county’s first human case of West Nile virus in July in a resident over the age of 50 with the mild form of the disease; the Nevada State Health Division on Friday reported one case in a Pershing County resident under the age of 50.

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.
  • Eliminate areas of standing water, including bird baths, un-maintained swimming pools and sprinkler runoff, which support mosquito breeding.

The health district’s mosquito surveillance program generally begins in spring and continues through the end of September. Environmental health specialists routinely survey and treat known breeding sources for mosquitoes and trap them for identification and testing for West Nile virus, Western equine encephalitis and St. Louis encephalitis.

In 2006, Nevada had a total of 123 human cases of West Nile virus, including one death. Three Clark County residents contracted the illness last year, all of whom contracted it while traveling outside of the area.

For more information or to report mosquitoes, “green” swimming pools or stagnant water sources, visit our website at or call the mosquito control hotline, (702) 759-1220.

Visit the Media Contacts webpage for media related inquiries.


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