West Nile Virus Update. No Human Cases Detected in Michigan

August 14, 2002

 

The Michigan Department of Community Health and the Michigan Department of Agriculture, today urged individuals to continue to take common-sense precautions to minimize exposure to mosquitoes to protect themselves from West Nile virus.

 

Confirming West Nile virus in crows in Michigan is not cause for panic or alarm, it simply reinforces the importance of minimizing exposure to mosquitoes, said Haveman. "We encourage individuals throughout the state to follow simple, common-sense precautions to protect themselves from mosquito borne illness.

 

The most sensitive indicator of West Nile virus activity is the presence of dead crows. Citizens are encouraged to report dead crow sightings to the West Nile virus toll-free hotline at 1-888-668-0869 or by clicking on "West Nile virus and on "2002 Specimen Collection and Submission Instructions. Selected crows will be sent to the Animal Health Diagnostic Laboratory at Michigan State University for testing.

 

"There is also no need for individuals to panic if they find a dead crow, said Wyant. "If the bird is found in a county where West Nile has already been detected and has been reported by calling the toll-free hotline or through the Internet, the crow can simply be properly disposed of. Individuals should always avoid barehanded contact when handling any dead bird. Use disposable gloves to put the dead bird in a double plastic bag. If gloves are not available, invert a plastic shopping bag and scoop up the bird with the bag. Once the bird has been reported, place the bagged carcass in an outdoor garbage can for disposal.

Additional crows will not need to be submitted for testing from the 32 counties--Bay, Berrien, Branch, Charlevoix, Clinton, Genesee, Grand Traverse, Gratiot, Huron, Ingham, Ionia, Kent, Lapeer, Lenawee, Macomb, Midland, Monroe, Montmorency, Muskegon, Oakland, Ontonagon, Oscoda, Ottawa, Saginaw, St. Clair, St. Joseph, Shiawassee, Tuscola, Van Buren, Washtenaw, Wayne and Wexford--where West Nile has been detected. Individuals from these counties are still urged to report the presence of dead crows through either the toll free hotline or website.

The virus is NOT transmitted from person-to-person or from crows to people. You cannot get it from touching or kissing a person who has the virus or from a health care worker who has treated someone with it. West Nile virus is transmitted to people by the bite of an infected mosquito. There are many ways to reduce the risk of becoming infected. They include:

• Applying insect repellent that contains the active ingredient DEET to exposed skin or clothing, always following the manufacturer's directions for use on the label.
• Avoid applying repellent to children under 2 years of age, and to the hands of older children because repellents may be transferred to the eyes or mouth potentially causing irritation or adverse health effects.
• Maintaining window and door screening to keep mosquitoes out of buildings.
• Draining standing water in the yard. Empty water from mosquito breeding sites, such as flower pots, pet bowls, clogged rain gutters, swimming pool covers, discarded tires, buckets, barrels, cans and similar sites in which mosquitoes can lay eggs.
• Wearing light colored long-sleeved shirts and long pants when outdoors.

Mosquitoes become infected with West Nile virus when they feed on infected birds that carry the virus in their blood. After 10 to 14 days, the mosquitoes salivary glands become infected and those infected mosquitoes can then transmit the virus to humans and other animals while biting them to take blood. During blood feeding, the mosquito injects the virus into the animal or human, where it multiplies and may cause illness. Crows are very susceptible to infection with West Nile virus and will die within two to three weeks of infection. Because of this, dead crows are the most sensitive indicator for the presence of West Nile virus in an area.

 

Most people infected with the West Nile virus have no symptoms of illness, but some may become ill three to 15 days after the bite of an infected mosquito. Health authorities believe about one in four infected persons will have mild illness with fever, headache and body aches, sometimes with skin rash and swollen lymph glands. Encephalitis is less common and may include headache, high fever, stiff neck, stupor, disorientation, coma, tremors, muscle weakness, convulsions and paralysis. In a few cases, mostly among the elderly, death may occur.

Horse owners are encouraged to contact their local veterinarian to discuss appropriate preventive measures. Prevention tips for horses include:

• Using approved insect repellants to protect horses.
• Placing horses in stables, stalls or barns during the prime mosquito exposure hours of dawn and dusk, and other times when mosquitoes are present, if possible.
• Eliminate standing water and drain troughs and buckets at least two times a week.
• Consulting with local veterinarian about using the recently developed vaccine to help control this disease in horses. The vaccine has been shown safe for use, and is expected to prove to be effective in studies.

The Michigan Departments of Community Health, Agriculture, and Natural Resources, Michigan State University Animal Health Diagnostic Laboratory and Michigan State University Department of Microbiology and Molecular Genetics all work cooperatively on surveillance activities for West Nile Virus in Michigan. Information on West Nile virus can be found at http://www.michigan.gov/mda, http://www.cdc.gov or by calling the West Nile virus toll free hotline at 1-888-668-0869. The most recent listing of counties where West Nile virus has been detected can be found at http://www.michigan.gov/mda and by clicking on "West Nile Virus, located along the right "Quick Links bar.