Weekly Update – August 13th – Mosquito Numbers Tick Up Slightly, More WNV Positive Samples
August 20, 2024
10 Reasons to Visit the MMCD Booth at the Minnesota State Fair!
August 29, 2024
The number of mosquitoes increased slightly last week and is above average for the first time since early spring..
The areas that saw the most rain in early August have higher than average mosquito numbers a few weeks later.
Every Monday night starting in mid-May through September, the Metropolitan Mosquito Control District sets out a variety of mosquito and black fly traps throughout the district and employs a network of sweep net collections done by employees and volunteers. Any insects collected are brought back to our lab on Tuesday to be identified throughout the week with maps published to show current mosquito and black fly activity.
Kids may be heading back to school and the State Fair might be already going strong, but don't count summer over yet! Mosquito numbers ticked up slightly last week for the second week in a row, with the most abundance coming in areas that saw more than 2 inches of rain in early August. The northern half of the District, especially Anoka County and northern Washington County are where the rain fell and the mosquitoes are currently above normal (though not as bad as they were this spring).
According to MMCD Entomologist Dr. Scott Larson, "Culex mosquitoes are still a concern, and they are abundant in some places as portrayed in the second map. However, Culex tarsalis mosquitoes are now really rare which bodes well for human [West Nile Virus] cases as they are the main vectors in the District." West Nile virus made some national news recently when Dr. Anthony Fauci was sickened by the disease from a mosquito bite he thinks he got in his backyard. More on West Nile virus in the District below.
Here are the maps from Monday-Tuesday, August 19th-20th:
Mosquitoes collected last week test positive for West Nile virus in Hennepin and Ramsey Counties
As we reported last week, we have collected mosquitoes that have tested positive for West Nile virus in all seven counties in the metro, and hot, humid weather tends to elevate the risk for WNV especially in the late summer months. Last week 6 out of 46 pools of mosquitoes tested positive for West Nile virus - 4 in Hennepin County and 2 in Ramsey County.
As we said last week, most of the species collected are Culex pipiens or Culex restuans, which rarely bite humans in Minnesota. The most prominent human-biting vector is Culex tarsalis which have relatively low numbers as of now. There have been two human cases reported to CDC in Minnesota this year, neither of which were in the District.
It's always important this time of year to take precautions to reduce mosquito bites including wearing bug spray and removing standing water.
Come See MMCD at the Minnesota State Fair!
Come see our booth in the Dairy Building at the Minnesota State Fair now through Labor Day! Our interactive booth features a lot of fun elements, including:
- Live mosquito larvae
- Microscopes to view specimens
- Coloring pages, temporary tattoos, and other fun stuff for kids
- Information about mosquitoes, ticks, and black flies
- Handouts about protecting yourself from mosquitoes
...and much more! We hope you stop by and see us!
