2021 is turning out to be an especially harsh West Nile Virus (WNV) year in Arizona. Here in Pinal County, Public Health has 22 cases under surveillance. This is much higher than normal as the average number of cases since 2016 has been 5 cases per season.
Though thankfully no fatalities have been detected in Pinal County so far this year; there have been four deaths associated with West Nile Virus in the State of Arizona. The average age of cases in Arizona is 62; however, the age range for reported cases is 22 to 91 years.
West Nile Virus is the leading cause of mosquito-borne disease in the continental United States. It is most commonly spread to people by the bite of an infected mosquito. Cases of WNV occur during mosquito season, which starts in the summer and continues through fall. This season, with our monsoon rains occurring early and often, WNV activity is significant in Arizona.
While 60-70% of cases do not experience symptoms, all cases reported in Pinal County so far have been symptomatic. West Nile Virus can cause a mild illness that lasts for a few days or a more serious condition that affects the central nervous system. The risk of developing a more serious disease increases with age, immune status, and presence of comorbidities.
Arizona has an above-average incidence of neuroinvasive disease caused by West Nile Virus at greater than 0.75 cases per 100,000 population. If you have had a recent mosquito exposure and experience symptoms like fever, fatigue, joint pains, stiff neck, or altered mental state, please consult your healthcare provider.
- Every person can take steps to help prevent the spread of West Nile Virus. Do not allow mosquitoes to breed on your property: Remove standing water, even in flower pots and dog bowls
- Keep swimming pools in operable condition
- If you must be outside when mosquitoes are present (most active at dawn and dusk), wear long-sleeve clothing and an EPA-approved and CDC-recommended mosquito repellant such as DEET or picaridin
Good resources to provide information about the West Nile Virus in Arizona
Arizona Department of Health Services click HERE to learn more.
Centers for Disease Control and Prevention click HERE to learn more.
The Environmental Health Division conducts mosquito monitoring throughout Pinal County with a focus on trapping, identifying, and testing mosquitoes in the populated areas most at risk for WNV. While not all mosquitoes can spread WNV, mosquito surveillance has shown an abundance of vector mosquito activity throughout the central and western portions of Pinal County.
Mosquito fogging occurs based on this surveillance, not on complaint activity. Pinal County Environmental Health’s abatement activities, including reduction or treatment of breeding sites and fogging for adult vector mosquitoes, is expected to continue through the end of the season. For updates on mosquito fogging activities, please call the Mosquito Hotline at 520-866-6200.
Click HERE to View Video About Pinal County's Vector Control Program