LAS VEGAS (KTNV) — Mosquitoes in 16 Southern Nevada zip codes have now tested positive for West Nile virus, the Southern Nevada Health District announced on Monday.
In a press release, the health district said results of its recent tests represent "the highest level of activity in the program's history this early in the season."
As of June 6, 91 mosquito pools containing 3,081 mosquitoes had tested positive for West Nile virus. Mosquitoes from two zip codes additionally tested positive for the virus that causes St. Louis encephalitis, health officials noted.
Mosquitoes in these zip codes tested positive for West Nile virus, according to the health district's most recent report:
- 89014
- 89030
- 89031
- 89032
- 89081
- 89101
- 89102
- 89104
- 89107
- 89108
- 89117
- 89120
- 89121
- 89128
- 89129
- 89146
The district is also reporting an increased number of complaints from the public about mosquito activity, officials said, which they attribute to the expansion of one particular mosquito in our region: Aedes aegypti.
These mosquitoes "are known to be aggressive daytime biters that prefer feeding on people instead of birds and have tested positive for West Nile virus for the first time in Clark County," officials stated.
Pest control experts previously told Channel 13 the Aedes aegypti mosquito is also unique in that it takes very little water for the mosquitoes to breed. In some cases, just a bottle cap of standing water can be enough — making it more difficult to contain the spread of these particular pests.
WATCH: Why are there so many mosquitoes in Las Vegas this year? We talked to a pest control expert to find out.
You're probably used to hearing about West Nile virus, but what is St. Louis encephalitis? As health officials explained, it's another virus spread through mosquito bites that can include symptoms like fever, headache, nausea, vomiting and fatigue.
While most people infected with this virus will not develop symptoms, "some people may develop a neuroinvasive form of the disease that causes encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes surrounding the brain and spinal cord)," health officials stated.
2019 was the last time mosquitoes carrying St. Louis encephalitis were last reported in Clark County, and the last reported cases in humans were in 2016, officials noted.
Mosquitoes in these zip codes were positive for St. Louis encephalitis:
- 89104
- 89115
As for West Nile virus, two human cases were reported in Clark County in 2023. In 2019, 43 human cases were reported, with minimal virus activity in the time since.
The virus is also spread to people through the bite of an infected mosquito, and can include symptoms like fever, headache, body aches, vomiting, diarrhea or rash.
"About one in 150 will develop more serious, sometimes fatal, illness," officials stated. "People who think they might have West Nile should talk with their health care provider."
