Authorities identified the West Nile virus in a pool of mosquitoes from Northbrook last Friday.
Found in the Somme Woods area, this is the third batch of mosquitoes that has tested positive for the virus in Northbrook this summer, according to the North Shore Mosquito Abatement District and the Northwest Mosquito Abatement District.
While there are no recorded cases of West Nile infections in people in Illinois this year, the virus had sickened state residents over the past several years, according to the Illinois Department of Public Health. The first human case occurred in 2002, when the virus struck more than 800 individuals. Flare-ups occurred in 2005 and 2006, when the state recorded 252 cases and 12 deaths and 215 cases and 10 deaths, respectively those years.
West Nile virus is carried by the Culex mosquito, otherwise known as the house mosquito, according to David Zazra, communications manager for the North Shore Mosquito Abatement District.
“These are container breeders, and they prefer really nasty containers of water that could be as small as a bottle cap,” he said.
Outbreaks of the disease are particularly common in northern Cook County, according to Zazra. “The climate is ideal,” he said.
Heavy rains may create the perfect breeding conditions for floodwater mosquitoes, but not for the type that carry the West Nile Virus. For the Culex mosquito, hot, dry weather is the ideal condition for breeding—exactly the weather northern Illinois experienced for most of July.
“We’re hoping that some of these larger storms may have decreased some of the population,” Zazra said.
According to the U.S. Centers For Disease Control and Prevention (CDC), roughly 80 percent of people infected by West Nile Virus do not show any symptoms. Milder symptoms, including fever, headache, body aches, nausea and vomiting, are common among the roughly 20 percent who do show symptoms.
“Let’s say you were bit by a mosquito and then three to 10 days afterward you start feeling like you have a headache or a fever, definitely go see a doctor,” Zazra said.
While the vast majority of infected people show no symptoms, about one in 150 may develop severe symptoms. These can include high fever, disorientation, coma, muscle weakness, vision loss, numbness and paralysis, according to the CDC.
Adults older than 50 are more at risk of developing serious symptoms, and should be more cautious about avoiding mosquito bites.
When it comes to personal protection, Zazra boils it down to two words: wear repellent.
“If you’re stepping outside to throw your garbage right now, wear repellent,” he said. “Cover up as much skin as possible with your clothing.”
In most cases, insect repellent should be sprayed directly on the skin, Zazra said. The majority of such products are less effective when sprayed on clothes and people should be follow directions on the package for maximum protection, he added.
Residents can prevent standing water from collecting on their property by cleaning catch basins and gutters and storing buckets upside down. A complete list of tips to avoid mosquitoes from breeding on your property can be found on the North Shore Mosquito Abatement District website.
Officials will be spraying in Northbrook to kill adult mosquitoes in the Somme Woods area when weather conditions are right, Zazra said. That’s the last step in the agency’s pest management program, which begins with efforts to kill mosquito larvae in early spring.
“We practice what’s called integrated pest management, and that entails first doing larval control and source reduction,” Zazra said. “It’s far more effective to do control at that level.”
Residents can contact the North Shore Mosquito Abatement District to report a dead bird or standing water problem at 847-446-9434. The Northwest Mosquito Abatement District can be reached at 847-537-2306.
Entrusted with reducing and controlling the mosquito population in the area, the district is funded through property taxes from several local townships. It covers the portion of Northbrook east of Pfingsten Road, while the Northwest Mosquito Abatement District covers Northbrook west of Pfingsten.