/SNHD Surveillance Detects West Nile Virus in 12 Mosquitoes in Clark County

SNHD Surveillance Detects West Nile Virus in 12 Mosquitoes in Clark County

September 7, 2006

LAS VEGAS – September 7, 2006 – The Southern Nevada Health District’s mosquito surveillance program has detected West Nile virus in 12 additional mosquitoes in Clark County. There have been a total of 17 mosquitoes testing positive in the county in 2006, all of which have been detected since August. Affected mosquitoes were found at the Gilcrease Bird Sanctuary and at the Las Vegas Wash/Calico Ridge. To date, there have been two confirmed cases of West Nile virus in Clark County residents; neither individual contracted the disease in Clark County. The first individual is under age 50, and contracted the illness while traveling in northern Nevada. The second case is an individual over the age of 50 who contracted the illness in Utah.

“As we move into late summer and early fall, we need to remind the public that there is still mosquito activity in the county and it is still important to take steps to minimize exposure to mosquito bites and to control the mosquito population,” said Dr. Donald Kwalick, the Southern Nevada Health District’s chief health officer.

The following preventive actions are recommended by the U.S. Centers for Disease Control and Prevention (CDC) to reduce individual risk of mosquito-borne illness:

  • Eliminate areas of standing water, including bird baths, un-maintained swimming pools and sprinkler runoff, which support mosquito breeding.
  • Make sure doors and windows have tight-fitting screens without tears or holes.
  • Avoid spending time outside when mosquitoes are most active, notably at dusk (the first two hours after sunset) and dawn.
  • Wear pants and long-sleeved shirts, when outdoors.
  • 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.

West Nile virus most often is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread the virus to humans and other animals when they bite. West Nile virus is NOT spread through casual contact such as touching or kissing a person infected with the virus.

According to the Centers for Disease Control and Prevention (CDC), most people infected with West Nile virus will not develop any type of illness or experience symptoms. It is estimated that 20 percent of the people who become infected will develop West Nile fever. Symptoms include fever, headache, tiredness and body aches.

Approximately one in 150 persons (less than one percent) infected with West Nile virus will develop a more severe form of the disease, West Nile encephalitis or meningitis. Symptoms of the more severe disease include severe headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.

While there is no specific treatment for West Nile virus infection, people who have been exposed to mosquitoes and experience symptoms of the more severe illness are encouraged to contact their health care provider immediately.

For additional information on West Nile virus, visit the health district website at www.southernnevadahealthdistrict.org. The public may also call the West Nile virus hotline at (702) 759-1220 with questions, concerns or to report standing water, dead birds and mosquitoes.

Visit the Media Contacts webpage for media related inquiries.


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.