/Twenty-eight cases of West Nile virus reported

Twenty-eight cases of West Nile virus reported

Health District declares outbreak — urges the public to protect themselves from mosquito bites

August 22, 2019

LAS VEGAS – The Southern Nevada Health District is declaring an outbreak of West Nile virus in Clark County after receiving reports of 28 cases of the disease in humans – the highest case count in a season since the virus was first detected in the state in 2004. In addition to the high number of cases, 17 of the 28 reported cases have had the more serious neuroinvasive form of the illness.

The Health District’s Mosquito Surveillance Program has identified both West Nile and St. Louis encephalitis virus-positive mosquitoes throughout Southern Nevada. West Nile virus-positive mosquitoes have been found in 39 unique ZIP codes, and mosquitoes testing positive for the St. Louis encephalitis virus have been found in 15 unique ZIP codes so far this season. More than 38,600 mosquitoes have been submitted for testing this year. This season 19 percent of mosquitoes have tested positive for West Nile or St. Louis encephalitis virus. Last season less than 0.1 percent tested positive for the virus. Updated reports on mosquito activity and human case counts are available on the Health District website each week at www.southernnevadahealthdistrict.org/programs/mosquito-surveillance/weekly-arbovirus-update/.

“The West Nile virus activity we are seeing in our community is a serious public health concern,” said Dr. Joe Iser, Chief Health Officer of the Southern Nevada Health District. “I urge people to protect themselves from mosquito bites by using repellents whenever they are outdoors and to make sure they are eliminating standing water from around their homes.”

The Health District is reminding the public that West Nile virus is preventable. The disease is transmitted by the bite of an infected mosquito. The illness is not spread person to person. Most people with the virus (eight out of 10) will have no symptoms or very mild symptoms of illness. About one in five people will develop mild symptoms which include fever with other symptoms such as headache, body aches, vomiting, diarrhea, or rash. Most people with this type of West Nile virus recover completely but fatigue and weakness can last for weeks or months. About one in 150 people who are infected develop a severe illness affecting the central nervous symptom such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord).

The most effective way to keep from getting infected with West Nile virus and other mosquito-borne illnesses is to prevent mosquito bites. In addition to using Environmental Protection Agency (EPA)-registered insect repellents containing DEET, Picaridin, IR3535, Oil of lemon eucalyptus (OLE), or 2-undecanone, wear light-colored, long-sleeved shirts and pants, and take steps to control mosquitoes in and around the home. Eliminate breeding sources, including non-circulating ponds, “green” swimming pools, and accumulated sprinkler runoff, which support mosquito breeding. For more tips, go to the Health District’s Mosquito Breeding Prevention website.

Mosquito activity can be reported to the Health District’s Mosquito Surveillance Program at 702-759-1633.


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.