/West Nile Virus

West Nile Virus

West Nile virus is a potentially serious illness that is most often spread through 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. West Nile virus has been detected in all lower 48 states (but not in Hawaii or Alaska) and outbreaks of disease have been occurring in the United States every summer since 1999.

The first human cases of West Nile virus in Clark County, along with the first positive mosquitoes, were reported in 2004. The health district conducts surveillance of mosquito populations to monitor the level of virus throughout the valley. Every year since then (except 2010), the virus has been found in both humans and mosquitoes. West Nile virus is now endemic in Clark County, which means we expect to see the virus every year during the mosquito season, which occurs April through November.

The most effective way to avoid West Nile virus disease is to prevent mosquito bites. You can play an important role in monitoring West Nile virus by reporting stagnant water, green swimming pools or other potential mosquito breeding sources to your local code enforcement agency. Visit the Mosquito Surveillance for more information on reporting mosquito activity to the health district. For additional information on West Nile virus visit the Frequently Asked Questions page or the Nevada Department of Agriculture’s website.

West Nile Virus – Public Health Updates & News Releases

2Sep 2021

Mosquitoes in Clark County test positive for West Nile Virus

Mosquitoes trapped by the Southern Nevada Health District’s Mosquito Surveillance Program in the 89014 ZIP code have tested positive for West Nile virus, the first this season in Clark County. The Health District is reminding people that “yes” there are mosquitoes in Southern Nevada, and to protect themselves from mosquito bites when they are outdoors.

18Jun 2020

Mosquitoes in Clark County test positive for West Nile Virus

Mosquitoes that tested positive as part of the Southern Nevada Health District Mosquito Surveillance Program’s trapping activities mark the first appearance of West Nile virus in Clark County this season. The mosquitoes were trapped in the 89120 ZIP code.

23Aug 2019

Public Health Update – Weekly Arbovirus Report: August 23, 2019

The Southern Nevada Health District Arbovirus report for the week of August 19-23 is available at www.snhd.info/wn-updates. The Southern Nevada Health District is reporting 10 additional West Nile virus cases for a total of 29 cases. The individuals are nine males, six of whom are over the age 50, three under the age of 50; and one female over the age of 50. Seven of the new cases have the more serious neuroinvasive form of the illness.

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Contact Information

(702) 759-1633

Updated on: October 21, 2019

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