The Maricopa County Department of Public Health is reminding the community to prevent mosquito bites with 26 human cases of West Nile virus infection reported this season, including two deaths. Both individuals who died were over 50 years old, the group that is most at risk for serious complications of West Nile virus.

Image/National Atlas of the United States
Image/National Atlas of the United States

“These tragic deaths serve as an important reminder to all of us to do our part in protecting ourselves, our family and our neighborhoods from mosquito-borne diseases,” said Dr. Rebecca Sunenshine, medical director of the Disease Control Division at Maricopa County Department of Public Health. “With all the recent rain we’ve had, it’s likely we’ll see more mosquito activity. Apply insect repellent and cover up whenever you are outdoors, and do your part to rid your property of water where mosquitos like to breed.”

West Nile virus is typically transmitted through the bite of an infected mosquito. It can cause severe illness in people and horses, although only about 20 percent of those infected will develop any symptoms at all. Those who do develop symptoms usually report fever, headache, body aches, and muscle weakness. Rarely, individuals might experience more severe symptoms including high fever, severe headache, neck stiffness, and/or encephalitis, which is inflammation of the brain. These severe cases can lead to paralysis or death, and usually occur in those over 50 years old.

Mosquito awareness has become increasingly important as the mosquitoes in many travel destinations in the Americas, Caribbean, Pacific Islands and Africa can transmit Dengue, Chikungunya and Zika virus. To date, Maricopa County has had only imported cases of these diseases, including eight cases of Dengue, three cases of Chikungunya, and 14 cases of Zika virus.

“Public Health is working very closely with our surveillance partners and healthcare providers to ensure we have a strong surveillance system for both humans and mosquitoes and prevention strategies in place,” said Dr. Sunenshine.

Maricopa County Health officials urge all people to “Fight the Bite” and follow simple precautions to avoid mosquitoes and the diseases they may carry:

  • Avoid mosquito bites day and night
  • Wear lightweight clothing that covers your arms and legs
  • Use insect repellents containing DEET, Picaridin, or other EPA registered repellants according to the product label on exposed skin and clothing
  • Make sure doors and windows have tight fitting screens and remain closed
  • Drain and remove containers that hold water from around your home where mosquitoes can breed such as plastic covers, buckets, old tires, plant trays, pet bowls, toys, and boats
  • Ensure that swimming pools and decorative water features are properly maintained

Maricopa County Environmental Services Department (MCESD) conducts a proactive and aggressive 12 month mosquito surveillance and abatement program. This year, MCESD’s lab has confirmed 60 West Nile virus positive mosquito samples. The trappings have yet to produce positive samples for Zika, Chikungunya, Dengue or Saint Louis encephalitis.

“With the recent West Nile virus-related deaths and the number of infected mosquitos with this virus in the County, we would like to remind everyone how critical it is to dispose of any standing water, which is required for mosquitoes to breed,” said Steven Goode, MCESD Director.  “If a resident or visitor notices any mosquito concerns in their communities, please call the MCESD Mosquito Information & Complaints Hotline at (602) 506-0700. The call will initiate investigation and follow-up with the appropriate level of monitoring and treating the area.”

In 2015, Maricopa County had 97 positive West Nile and 60 positive St. Louis encephalitis mosquito samples. Additionally, there were 62 West Nile virus cases with two deaths and 22 St. Louis encephalitis cases with two deaths.