Washtenaw Health Department Begins Surveillance For West Nile Virus

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West Nile Virus

Washtenaw County Public Health Department officials have begun surveillance activities for the seasonal West Nile virus, a mosquito-borne virus that can cause mild-to-severe illness in humans and other animals.

County residents are urged to take precautions to prevent mosquito bites and to call the Washtenaw County West Nile Virus Hotline at (734) 544-6750 to report dead birds or to receive general West Nile virus information.

Although there have been no confirmed cases of West Nile virus in the county to date, mosquitoes emerging from winter hibernation may be infected with the virus and pose a health risk to the general public. Hot, dry weather conditions are favorable for amplifying the virus cycle in birds and mosquitoes, particularly in urban and suburban areas. In Michigan, August and September are the months of greatest risk to humans for becoming infected with the West Nile virus.

"While we have not traditionally experienced a large number of human cases of West Nile in Washtenaw County, it's important for communities to be vigilant for signs of active transmission of the virus and to be prepared in the event of an outbreak" said Dr. Stan Reedy, Washtenaw County Medical Director. "Individuals can help us protect the public's health by reporting dead birds in their area, taking precautions to prevent mosquito bites, and supporting community-based mosquito control programs."

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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, robins, and ravens is a sensitive indicator for the presence of the West Nile virus.

Nationally, cases of West Nile virus increased in 2006, with 4,256 human cases and 165 deaths. Michigan accounted for 55 human cases, with 7 deaths. Washtenaw County had one human case, with no deaths. As in 2005, most of the human cases occurred in Wayne and Kent counties.

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. In a few cases, mostly among the elderly, death may occur. Mild illness from West Nile can include these symptoms: Slight fever, headache, body aches, and sometimes a skin rash and swollen glands. Serious illness from West Nile can include these symptoms: High fever, severe headache, stiff neck, mental confusion, convulsions, muscle weakness, and paralysis.

The Washtenaw County Public Health Department asks citizens to report all dead birds to the Washtenaw County West Nile Virus Hotline at (734) 544-6750. If a crow, raven, or blue jay has been dead for less than 48 hours and/or shows no signs of advanced decomposition, it may be collected for testing. Once a zip code has produced a positive test result, no more birds will be accepted from that zip code. Residents, however, should continue to report any dead birds they see. Dead bird reports are entered into a mapping database to predict the level of virus activity in a particular geographic area.

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:

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