West Nile Virus Detected in Mosquito Samples from Multiple States

Mosquitoes positive with West Nile virus have been found in a variety of samples throughout the United States.

Here is a look at recent activity from various media outlets.

Colorado. A sample of mosquitoes in Weld County tested positive for West Nile virus according to the Colorado Department of Public Health and Environment. The infected mosquitoes were detected using the county's weekly mosquito testing for West Nile. A report-based detection system is used, which depends on reports from the public to track cases. There have been no human cases of West Nile in Colorado so far this year. In 2020, 35 people in Colorado contracted the disease and one person died as a result. Source: The Gazette. 

Illinois. The Chicago Department of Public Health announced a group of mosquitoes tested positive for West Nile. Four pools were positive of the 108 tested between July 5 and 9. Mosquito traps and testing have been occurring in the area since late May. There have not been any human cases of West Nile in Chicago so far this year. CDPH will continue to monitor mosquito samples and 40,000 catch basins will be treated with larvicide. Source: WTTW. 

Indiana/Ohio. Health officials in Indiana and Ohio are urging people to be cautious because West Nile has been detected in mosquitoes in both states. A sample collected in Vigo County, Ind., tested positive, as well as a sample taken from a park in Toledo, Ohio. No human cases have been detected in the area, but experts expect to see more West Nile activity this year. Source: WLWT.

Oklahoma. According to Tulsa Health Department officials, a sample of mosquitoes in a trap in Tule County tested positive for West Nile. THD runs a mosquito surveillance program where traps are set weekly in places throughout Tulsa County. The caught mosquitoes are tested on a weekly basis. The program begins each May. There are no confirmed cases of West Nile virus in humans so far this year. Source: KJRH.

Texas. The first human case of West Nile virus in Dallas County for 2021 was detected. Positive West Nile mosquito samples have been found in Cedar Hill, Dallas, Highland Park, Mesquite and University Park. These cases have led to scattered spraying in order to decrease the mosquito population. Source: NBC DFW.