July 23, 2007
State medical experts are reminding people of ways to prevent mosquito borne illnesses after analyzing data collected since the first report of West Nile Virus in Wisconsin.
The study, published in the Wisconsin Medical Journal, identified 114 confirmed cases of the disease and seven fatalities from 2002 to 2006. The majority of those illnesses — 82 percent statewide — came during August and September.
Nearly three of four West Nile patients remembered receiving mosquito bites in the two weeks prior to their illness, according to the study. But 49 percent of those case patients reported never wearing insect repellent, a statistic the study’s authors called alarming.
“Protection and prevention measures are important statewide, especially during July through September when the risk is greatest,” reads the report, written by officials from the Wisconsin Division of Public Health, Wisconsin State Laboratory of Hygiene and the La Crosse County Health Department.
The mosquitoes that make barbecues miserable in rainy years — the ones that are noticeably absent from backyards during this dry summer — are not usually not West Nile carriers. Those peskier mosquitoes are often rain water breeders, and this summer has not been rainy, according to University of Wisconsin-Madison Extension enthomologist Phil Pellitteri.
“You’ve got no water, you’ve got no mosquitoes,” he said.
Wisconsin’s 54 different types of mosquitoes carry a few other diseases, but its usually the species in the Culex genus which carry West Nile virus. While the nuisance mosquitoes have had less rain and flood waters to breed in, the Culex bugs can reproduce in small amounts of stagnant water.
“In the Wisconsin situation, the mosquitoes that bother most of us don’t breed in your backyard,” Pellitteri said. “Culex is more likely a local mosquito. In the ccase of a birdbath or pool, that’s not as dependent on rain water.”
Pellitteri said Culexes seem to feed on birds more often in the spring, then make a transition to large mammals such as humans and horses.