/Southern Nevada Health District reports first West Nile virus death in Clark County

Southern Nevada Health District reports first West Nile virus death in Clark County

October 17, 2019

LAS VEGAS – The Southern Nevada Health District is reporting the first West Nile virus death in a Clark County resident. The individual was a female over the age of 50 and had previously been reported as having neuroinvasive illness.

In August, the Health District declared an outbreak of West Nile virus in humans after reaching the highest case count in a season since the virus was first detected in the state in 2004. In addition to the increased number of reports, many of the reported cases had the more serious neuroinvasive form of the illness.

“This case is a tragedy, and we want to remind the public that mosquitoes can pose serious health threats,” said Dr. Michael Johnson, Director of the Community Health Division for the Southern Nevada Health District. “Fortunately, there are steps people can take to protect themselves from mosquito bites throughout each season. I would encourage everyone to continue to use repellents whenever they are outdoors and to make sure they are eliminating standing water from around their homes.”

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 system such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). Recovery can take several weeks or months, and the effects on the central nervous system may be permanent. Approximately one in 10 people who develop the neuroinvasive form of West Nile virus die from the illness.

The Health District has concluded its mosquito surveillance activities for the season. As of October 11, the agency had received reports of 43 cases of West Nile virus, with 34 cases having had the more serious neuroinvasive form of the illness. The Centers for Disease Control and Prevention reports that as of October 15, a total of 46 states and the District of Columbia have reported West Nile virus infection in people, birds, or mosquitoes. There have been 731 cases of West Nile virus disease reported to the CDC as of this date. Of those cases, 472 (65 percent) were classified as neuroinvasive disease.

The Health District’s Mosquito Surveillance Program identified both West Nile and St. Louis encephalitis virus-positive mosquitoes throughout Southern Nevada. West Nile virus-positive mosquitoes were found in 43 unique ZIP codes, and mosquitoes testing positive for the St. Louis encephalitis virus were found in 15 unique ZIP codes. More than 43,000 mosquitoes were submitted for testing. Weekly arbovirus surveillance reports for the season are available on the Health District website at www.southernnevadahealthdistrict.org/programs/mosquito-surveillance/weekly-arbovirus-update/.

While mosquito activity does wane in Southern Nevada during the cooler months, mosquitoes can stay active throughout the year. More information on how to control mosquitoes at home and in the community is available on the Health District’s Mosquito Breeding Prevention website.


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.