/Health District identifies first West Nile-positive mosquitoes of the season

Health District identifies first West Nile-positive mosquitoes of the season

Reminds Southern Nevadans to Fight the Bite

July 27, 2018

LAS VEGAS – The Southern Nevada Health District’s Mosquito Surveillance Program identified the first West Nile virus-positive mosquitoes of the season in the 89122 ZIP code. To date, there have been no human cases of West Nile illness reported. Updated information on positive mosquito submission pools and mosquitoes that are tested in Clark County is posted on the Health District’s website.

“As we continue through monsoon season, it is important to remind Southern Nevadans to take steps to eliminate mosquito breeding sources to protect themselves and their families from mosquito bites,” said Dr. Joe Iser, Chief Health Officer. “Community members can do their part by ensuring their homes are free of standing water, using insect repellent appropriately, and reporting mosquito activity to our agency.”

Mosquitoes acquire West Nile virus by feeding on infected birds. The illness is not spread from person to person. Many people with the virus will have no symptoms or very mild clinical symptoms of illness. Mild symptoms include fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach, and back. In some cases, the virus can cause severe illness and even death. In 2017, the Health District reported three cases of West Nile virus. For information about prevention tips, visit the Health District’s Mosquito Surveillance page.

The Health District’s Mosquito Surveillance Program is continuing its surveillance to identify the Aedes aegypti mosquitoes, which are capable of transmitting Zika, chikungunya, and dengue. Unlike mosquitoes that can transmit West Nile virus and are most active at dawn and dusk, Aedes mosquitoes are more aggressive during the day. They are known to breed near homes, in smaller water sources, and primarily bite humans. Since they were first identified in 2017, the Aedes aegypti mosquitoes have been found in the 89130, 89131, 89031 and 89032 ZIP codes.

In addition to Zika, West Nile virus, and St. Louis Encephalitis, the Southern Nevada Health District’s Mosquito Surveillance Program regularly tests mosquito pools for Western Equine Encephalitis, which is occasionally identified in Clark County. Residents can report green swimming pools and standing or stagnant water sources to local code enforcement agencies. Contact information for local jurisdictions’ code enforcement is available on the Health District website.

Residents are urged to report all mosquito activity to the Health District, particularly day-biting mosquitoes. Mosquito activity can be reported to the Mosquito Surveillance Program at (702) 759-1633.

Mosquito Control

  • Check your yard for water-filled containers weekly or after every use of sprinklers or rain.
  • Throw away or recycle water-holding containers that are not needed.
  • If storing boats, old appliances, containers, or other large objects, they should be covered, turned over, or placed under a roof that does not allow them to fill with water.
  • Clean and scrub bird baths and pet-watering dishes weekly and dump the water from overflow dishes under potted plants and flower pots.
  • Fill tree holes and other cavities in plants with sand or soil.
  • Eliminate areas of standing water around your home, including non-circulating ponds, “green” swimming pools, and accumulated sprinkler runoff, which support mosquito breeding.
  • Check for hidden bodies of water such as wells, septic tanks, manholes, clogged drains, etc.
  • Call the Health District to report mosquitoes.

Prevent Mosquito Bites

  • Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, Picaridin, IR3535, oil of lemon eucalyptus (OLE), or 2-undecanone. Always follow instructions when applying insect repellent to children.
  • Do not use insect repellent on babies younger than 2 months old.
  • Do not apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin.
  • Adults: Spray insect repellent onto your hands and then apply to a child’s face.
  • Do not use products containing oil of lemon eucalyptus (OLE) or para-menthane-diol (PMD) on children under 3 years old.
  • Wear pants and long-sleeved shirts to reduce mosquito exposure when outdoors.
  • Make sure doors and windows have tight-fitting screens without tears or holes.
  • If you are outdoors in a mosquito-infested area, place mosquito netting over infant carriers.
  • Use mosquito netting when sleeping outdoors or in an unscreened structure.

For more information on mosquito surveillance activities in Southern Nevada, access the Southern Nevada Health District website. For additional information on eliminating breeding sources, access the CDC’s Controlling Mosquitoes at Home webpage.



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.