The Southern Nevada Health District received confirmation that the first Aedes aegypti mosquitoes identified in Southern Nevada have tested negative for the Zika virus. Testing for Zika was completed on two of the mosquitoes by the Nevada Department of Agriculture Animal Disease Laboratory. As Aedes aegypti is a new to Nevada, the third mosquito was sent to the Centers for Disease Control for reference laboratory confirmation.

The mosquitoes were identified by the Health District’s Vector Surveillance Program in the 89032 ZIP code area of Clark County on May 31. Health District staff will continue conducting surveillance to determine the scope of the Aedes mosquito population in the area and providing nearby residents with breeding prevention information throughout the weekend. The immediate area where the Aedes mosquitoes were first detected was treated as part of the Health District’s mosquito control efforts. The Health District has conducted surveillance for the Aedes mosquito species since 2014.

“Our environmental health specialists are talking to residents, providing them with information about eliminating breeding sources, and asking if they can set traps on their property. This is an opportunity to work with the community to be proactive and put preventive measures in place,” said Dr. Joe Iser, Chief Health Officer of the Southern Nevada Health District. “With the detection of this new species in our community and the report of our first case of West Nile virus, it is important to remind everyone to take steps to eliminate mosquito breeding no matter where you live in the Las Vegas area.”

The Aedes aegypti mosquito is the main type of mosquito that spreads Zika, dengue, chikungunya, and other viruses. Before being identified in Southern Nevada, the Aedes species has been identified in California and Arizona. To date, mosquitoes in those states have not tested positive for the Zika virus. Aedes aegypti mosquitoes can become infected if they bite an infected person while he or she still has the virus in their blood. The mosquito then needs to live long enough to bite someone after the virus has had time to multiply in its system.

The Health District reported 22 cases of Zika virus in Clark County residents in 2016. Twenty-one cases were travel-associated, and one was sexually transmitted. There has been one travel-associated case reported in 2017. In addition to mosquito bites, Zika virus can be spread from a mother to her baby during pregnancy, and it can spread during sex from an infected person to his or her partners.

Residents are urged to protect themselves from mosquito bites. 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 and primarily bite humans. Residents are urged to report all mosquito activity to the Health District, particularly day-biting mosquitoes. Mosquito activity can be reported to the Vector Surveillance Program at (702) 759-1633.

Mosquito Control

  • Check your yard weekly for water-filled containers or after every use of sprinklers.
  • Throw away or recycle water-holding containers that are not needed.
  • If empty containers or large objects, such as boats or old appliances must be stored, 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 up-to-date information on Zika and travel recommendations visit the CDC website. For more information on mosquito surveillance activities in Southern Nevada access the Southern Nevada Health District website.

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