Washtenaw County Health Department Begins Surveillance for West Nile Virus
Public Urged to Prevent Mosquito Bites and to Report Dead Birds
YPSILANTI, Mich., May 7, 2013 - Washtenaw County Public Health officials announced they have begun surveillance activities for the seasonal West Nile virus, a mosquito-borne virus that can cause severe illness or even death in humans, birds, horses and other animals. County residents are urged to take precautions to prevent mosquito bites and to call the Washtenaw County West Nile Virus Information Line at (734) 544-6750 to report dead birds or to receive general information.
After several years of sporadic cases, West Nile virus reappeared last summer as a threat. The hot, dry weather has been identified as a key factor for this increase in activity, as those conditions are favorable for the type of mosquitoes most likely to transmit the virus. In 2012, Michigan had 202 human cases with 17 deaths, and Washtenaw County had four human cases and one death. In the United States, there were 5,387 human cases and 243 deaths in 2012. This was the highest number of cases and deaths from West Nile virus, nationwide, since 2003.
“Last year was a good reminder that this virus is something we should all be prepared for, and take appropriate precautions against,” says Dick Fleece, Washtenaw County Health Officer.
There have been no confirmed cases of West Nile virus in Washtenaw County this year to date. In Michigan, August and September are the months of greatest risk to humans for becoming infected with the West Nile virus.
Most people infected with West Nile virus do not have any symptoms of illness, but one in four will become ill 3-15 days after the bite of an infected mosquito. People over age 50 are at higher risk of severe illness. In a few cases, mostly among the elderly, death may occur. Symptoms of mild illness from West Nile can include slight fever, headache, body aches and sometimes a skin rash and swollen glands. Serious illness from West Nile can include symptoms of high fever, severe headache, stiff neck, mental confusion, convulsions, muscle weakness and paralysis. Anyone with severe symptoms or with concerns about their health should consult with their health care provider.
Dead Bird Surveillance
Mosquitoes become infected with West Nile virus when they feed on infected birds that carry the virus in their blood. People are primarily exposed to West Nile from the bite of a mosquito that is infected with the virus. The presence of dead crows, blue jays and ravens is a sensitive indicator for the presence of the West Nile virus in a particular geographic area, as these birds often die soon after becoming infected.
Washtenaw County Public Health asks citizens to report all dead birds to the Washtenaw County West Nile Virus Information Line at (734) 544-6750. Washtenaw County will not be testing any birds for West Nile virus. Dead bird disposal instructions are available on the information line.
Personal Protection and Prevention
“Don’t let West Nile scare you away from enjoying the outdoors. Do try to protect yourself and your children from mosquito bites,” says Dr. Alice Penrose, Washtenaw County Medical Director.
Since West Nile virus is spread to humans almost exclusively through the bite of an infected mosquito, it is important for individuals to prevent mosquito bites through the following prevention activities:
• Wear light colored clothing, long-sleeved shirts, and long pants, if possible.
• Apply insect repellant that contains the active ingredient DEET, Picaridin/KBR 3023, Oil of Lemon Eucalyptus/PMD or IR3535 to exposed skin or clothing, especially when mosquitoes are most active (dawn and dusk). Always follow the manufacturer’s directions for use. DEET repellant can be used on children 2 months of age and older. Avoid applying repellant to the hands of young children who may then transfer the repellant to their eyes and mouth, which has the potential of producing irritation or adverse health effects.
• Take care when opening doors so that mosquitoes don’t “hitch a ride” into the house on you, your children or your pets.
• Maintain window and door screening to help keep mosquitoes out of homes and other buildings.
• Limit mosquito breeding sites by draining standing water in your yard. Empty water from flower pots/saucers, clogged gutters, wading pools, swimming pool and patio furniture covers, discarded tires, buckets and other items that can collect water. Change the water in birdbaths and horse troughs at least two times a week. Remove wet, organic material from your gutters and from low-lying areas in your yard.
• Keep tall weeds trimmed back from areas where you or your children spend time outdoors.
Mosquito Larval Surveillance and Control
Communities are encouraged to monitor mosquito larval populations, and to treat storm water catch basins and other areas of standing water with larvacide. Research has shown that communities with mosquito control historically have fewer cases of West Nile infection.
Many options are available for mosquito larval control, including new products considered to be less harmful to the environment. “The University of Michigan will treat catch basins across campus this year with an environmentally safe larvacide product, called Natular,” says Terry Alexander, Executive Director, Occupational Safety & Environmental Health and Office of Campus Sustainability. “The active ingredient is derived from a naturally occurring soil bacterium that inhibits larvae development into adult mosquitoes.”
More information about the West Nile virus is available on these county, state, and national websites:
Washtenaw County's activities regarding West Nile virus are a partnership involving the Washtenaw County Public Health Department, Washtenaw County Environmental Health Division, Michigan State University Extension, the University of Michigan and volunteer entomologists. These units comprise the Washtenaw County West Nile Virus Task Force. The Task Force's approach to prevention focuses on communication, education, outreach activities, surveillance, personal protection and mosquito control recommendations.