2025 Mosquito Surveillance Report

While the 2025 mosquito surveillance season concluded over two months ago, here is our final mosquito surveillance data. The results are interesting and I’m sure more will come from them as we further analyze the data.

Here is a quick breakdown of what we did locally, regionally, and statewide.

Marion County Highlights

• 4,056 mosquitoes collected with 3,045 grouped into 113 pools
• 22 pools tested positive for WNV (19.5% positivity rate)
• Highest positivity rate among six neighboring counties who conducted surveillance
• 15 mosquito species identified locally

While Richland and Hancock Counties collected and tested a much larger number of mosquitoes (19,275 and 6,913, respectively), their positivity rates were lower—7.8% and 13.5%. Delaware, Knox, and Wyandot Counties reported smaller surveillance programs with low to moderate activity, ranging from 2.1% to 8.8% positivity.

Statewide Overview

• 42 mosquito species identified statewide
• 478,139 mosquitoes collected; 397,257 tested in 11,980 pools
• 2,329 pools tested positive for WNV (19.4% positivity rate)

This year’s data show that our results closely match statewide averages for virus positivity, demonstrating the reliability of our efforts. These results also highlight the importance of ongoing trapping, testing, and prevention efforts to protect community health and guide our 2026 vector control strategies.