The number of positive West Nile virus samples is increasing in Maricopa County, according to officials.
The Maricopa County Environmental Services Department is reporting 150 positive cases so far in 2023 — more than double the number reported in all of last year.
The number of positive mosquito samples varies greatly each year — in 2021 there were more than 760 positive samples, while in 2020 there were just 10.
The department has mosquito-trapping locations throughout the country that collect mosquitoes for testing. The mosquitoes are pooled together, by species, into groups of 1-50 mosquitoes before they are processed for diseases.
That data helps officials determine areas of concern, if there are any, throughout the Valley.
Officials say West Nile virus is primarily spread through the bite of infected Culex species mosquitoes, which are found in Maricopa County and across the state.
"These mosquitoes generally bite from evening to early morning so it is important to protect against mosquito bites whenever you are outside," officials say.
The county has recorded 66 cases of West Nile virus so far this year, with a half-dozen confirmed deaths.
In 2022, there were 46 cases and less than 5 deaths. In 2021, there were 1,480 cases and 101 deaths.
The Environmental Services Department offers the following “4 Rs” tips to “fight the bite”:
- REPEL mosquitoes using EPA-registered insect repellent
- REMOVE standing water from your home and yard
- REPAIR or replace damaged window and door screens
- REMIND your family, friends and neighbors about mosquito safety
