Surveys for the Zika Mosquito: During 2017, locations in 5 Wisconsin counties (Dane, Rock, Milwaukee, Kenosha, La Crosse) were selected for surveys of the Asian tiger mosquitoes (Aedes albopictus). In late June, 2017, 3 specimens were collected in Dane County. None of these mosquitoes were collected during 2016 surveys of 20 Southern Wisconsin counties. The traps are containers which are attractive to female Asian tiger mosquitoes that are looking for a place to lay eggs. The eggs are sent to the Medical Entomology lab for hatching and identification of the larvae.
West Nile Virus: Results are for weekly traps maintained by Milwaukee Public Health and Dane County Public Health. For 2017, Dane County will use 6 traps which collect all types of mosquitoes that are seeking hosts. These traps use light and carbon dioxide to bait the mosquitoes. In 2017, Milwaukee will be surveyed with 20 traps that collect the Culex mosquito when it is looking for a place to lay eggs. These “gravid” traps use a strong smelling watery bait to attract the mosquitoes. Because these mosquitoes have already taken a blood meal (which they turned into eggs), they are more likely to be positive for West Nile virus than the mosquitoes collected in the light/carbon dioxide traps, which may be host seeking for the first time. Traps are put out weekly, with collections sent to the Medical Entomology lab for sorting, identification, counting, and testing.