/Public Health Update West Nile Virus

Public Health Update West Nile Virus

October 2, 2012

CORRECTED: Due to an error, the health district reported on Oct. 2 that one local horse was euthanized as a result of West Nile illness. The horse was not euthanized and is still alive.

The Southern Nevada Health District is reporting four additional human cases of West Nile virus. The patients, a 25-year-old woman with the more serious neuroinvasive form of the illness; a 52-year-old man with the less serious form of the illness; a 68-year-old woman and a 64-year old man, both with the more serious neuroinvasive form of the illness and both of whom are hospitalized. The health district reported its first 2012 case in September in a 75-year-old woman. That patient, who was hospitalized, has since died; she is the fourth West Nile-related death in Clark County since 2003. This brings the number of 2012 West Nile cases in Clark County to five.

In addition, the health district reports that it has identified a second West Nile-positive mosquito pool in the 89145 zip code. Previously, the health district’s vector control program identified positive mosquitoes in the 89107 zip code. The Nevada Department of Agriculture reported that a horse in the 89130 zip code contracted West Nile. The horse was unvaccinated. There is currently no vaccine for people. The link to the Department of Agriculture is: http://agri.nv.gov/Animals/Animal_Home/.

Recently, the Centers for Disease Control and Prevention announced that West Nile virus infections and illness rates are on record pace this year with more than 3,500 cases and 147 deaths reported through September 25. The health district reminds the community to take precautions to prevent against West Nile virus.

With the identification of two positive mosquito pools in Clark County it is likely that West Nile virus infected mosquitoes are present throughout the valley and precautions against the disease are recommended for all residents and visitors.

West Nile virus can be prevented by using insect repellants and eliminating sources of standing water which support mosquito breeding. For information about prevention tips, visit the health district’s West Nile virus pages on its website: http://www.southernnevadahealthdistrict.org/west-nile/index.php

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. Many people with the virus will have no symptoms or very mild clinical symptoms of illness. Mild symptoms include fever, headache, body aches, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach, and back. In some cases the virus can cause severe illness and even death. In 2011, Nevada reported 16 cases, 11 of which were in Clark County. There were no human cases of West Nile virus were reported in Clark County in 2010.

The health district’s environmental health specialists routinely survey and treat known breeding sources for mosquitoes and trap them for identification. However, the health district is no longer treating breeding sources on private property, such as green pools. Residents can now report green swimming pools and standing or stagnant water sources to local code enforcement agencies. Contact information for local jurisdictions’ code enforcement is available on the health district website at: http://southernnevadahealthdistrict.org/forms/mosquito.php.

In addition to West Nile virus, mosquitoes are also tested for Western equine encephalitis and St. Louis encephalitis.

The health district recommends the following to prevent mosquito bites and to eliminate breeding sources:

  • 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, “green” swimming pools and sprinkler runoff, which support mosquito breeding.

Updated information about the Southern Nevada Health District can be found on Facebook www.facebook.com/SouthernNevadaHealthDistrict, on YouTube www.youtube.com/SNHealthDistrict or Twitter www.twitter.com/SNHDinfo The health district is now available in Spanish on Twitter www.twitter.com/TuSNHD. Don’t have a Twitter account? Follow the health district on your phone by texting “follow SNHDinfo” to 40404.

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.