Local News


West Nile virus outbreak declared by Southern Nevada Health District

Posted: 8:28 AM, Aug 22, 2019
Updated: 2019-08-22 11:46:48-04
Clark County woman diagnosed with West Nile

LAS VEGAS (KTNV) — A West Nile outbreak has been declared by the Southern Nevada Health District.

The outbreak was declared after the health district was notified of 28 cases of the disease in humans; the highest total since the virus was first detected 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.

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).