Arizona health officials are reporting the first confirmed human case of West Nile Virus in Arizona this season in Maricopa County. The infected individual is a male resident in his late 50’s with no travel history. He experienced flu-like symptoms, but was not hospitalized and has since recovered.

maricopaThis has prompted health officials to advise residents to protect themselves and their homes against mosquitoes because of the risk not only West Nile virus, but also other mosquito borne viruses like St. Louis encephalitis virus and Western equine encephalitis.

This is the time of year when we see an increase in mosquito-borne diseases that can cause serious illness, and in some cases can be deadly,” said Dr. Rebecca Sunenshine, medical director for the Disease Control Division at the Maricopa County Department of Public Health (MCDPH). “While this is our first confirmed case, there are likely many more out there and we expect our numbers to rise as the monsoon season continues.”

West Nile virus can cause severe illness in people and horses, although only about 20% of those infected will develop any symptoms at all, usually flu-like: fever, headache, body aches, and muscle weakness. Some people, especially the elderly, may experience severe disease including high fever, headache, neck stiffness, and/or encephalitis or inflammation of the brain, which can lead to paralysis or death. There were 108 human cases of West Nile virus reported statewide in 2014, 93 of which were in Maricopa County.


Mosquito populations increase dramatically during periods of high rainfall, and can spread serious diseases to people.

“By following a few simple guidelines you can reduce the risk of these diseases for yourself and your family,” said Dr. Cara Christ, director of the Arizona Department of Health Services.

To prevent the spread mosquito-borne diseases, please follow the prevention guidelines:

  • Wear mosquito repellant or long sleeved shirts and pants when outside.
  • Check your home for any containers that could hold water after rains or irrigation, including old tires, bottles, drums, and buckets.
  • Ensure water-holding containers are covered or turned over to protect them from mosquito eggs.
  • Make sure doors and windows have tightly fitted screens. Repair or replace screens with tears or holes in them.
  • Clean and change the water in flower vases, birdbaths, planters and animal watering pans at least once a week.
  • Repair leaky pipes and outside faucets.

Dr. Christ said people could also be infected with diseases from mosquitoes while traveling outside of Arizona. Some of the more common mosquito-borne diseases associated with travel include dengue, chikungunya, yellow fever, and malaria.
“It’s possible for someone to visit an area where there are mosquitos that carry a disease, such as dengue, and bring the disease back to Arizona,” Dr. Christ said. “Taking a few extra precautions will not only help you protect your own health, but also the health of our entire state.”

In 2014, 108 cases of West Nile virus and one case of St. Louis encephalitis were reported among Arizona residents. In addition, 91 cases of dengue and 16 cases of chikungunya were reported among persons who had traveled outside of Arizona in 2014. Dengue and chikungunya have currently not been found in Arizona mosquitoes.