White dots on catch basin grates in KPVillas indicate the basin or dry well is holding water when it was visited by the St. Joseph County (SJC) Health Department on February 23, 2024. SJC is targeting mosquito larvae to eliminate vector borne diseases like West Nile virus.
In February 2024, SJC Council Commissioners approved the budget for an enhanced mosquito control project, per Brett Davis, Assistant Director of Environmental Health for the SJC Health Department. "This is part of a lot of the new initiatives the Health Department is undertaking as a result of 2022's SB4, the Health First Indiana big investment in public health throughout the state....We now have capacity to embellish what we have and make it more effective."
Staff from the Health Department will re-visit after a period of dry weather and see which catch basins and storm water dry wells are holding water still. If necessary, at a later date they'll come back and drop larvacide packets in the wells to kill mosquitoes. The larvacide releases slowly over 30 to 180 days, depending on the product used.
Anything holding water a week or longer is stagnant enough that mosquitoes will want to lay eggs there. The hotter the weather, the quicker the West Nile mosquito life cycle. Mosquitos transition from egg to flying adult in 2-3 weeks. The extended period of the larval stage in water is when they are more vulnerable and treatment is more efficient than trying to kill them in the air.
The Health Department's intention is to lessen West Nile Virus, for which SJC starting testing around 2020.. Mosquitoes are also responsible for spreading Eastern Equine Encephalitis (EEE).
SJC is one of four counties in the state who can do their own testing. In house, SJC can test up to 50 mosquitos at a time. Tests sent downstate to the IN Dept. of Health can test batches up to 100 mosquitos at a time. Individual traps set by SJC collect from 10 to 600 mosquitos. Last year yielded the highest result from traps, with over 150 tests coming back positive.
If SJC has a large haul of hundreds of mosquitos from a single trap, it may send some downstate and test some in house. They all get tested in order to be as data accurate as possible, Davis said.
St. Joseph County has more mosquito-related content online at https://www.in.gov/localhealth/stjosephcounty/environmental-health/pests-and-vectors/mosquitoes/.
While SJC has treated positively for mosquitos in the past such as spraying from a truck, the new program intends to interrupt mosquito life cycle earlier in the long larval stage.
For more information on regional efforts, the Midwest Center of Excellence for Vector-Borne Disease is a collaboration that includes Purdue and Notre Dame, as reported in the South Bend Tribune in Sept. 2022.