West Nile Virus Update

June 26, 2002

 

The Michigan Departments of Community Health and Agriculture today provided a West Nile Virus testing update.  West Nile virus was detected for the first time in mosquitoes and birds in Michigan in 2001 and was expected to been seen again in 2002. 

 

Recent laboratory testing conducted by the Michigan State University Animal Health Diagnostic Laboratory and confirmed by the Department of Community Health has determined a crow found in Clio in Genesee County has tested positive for West Nile Virus.  Previously, a crow found in Livonia and a crow found in Mason also tested positive for West Nile Virus.

 

“Confirming West Nile in these crows is not cause for panic or alarm, it simply reinforces the importance of minimizing exposure to mosquitoes,” said Department of Community Health Director James K. Haveman, Jr.  “We encourage individuals throughout the state to follow simple, commonsense precautions to protect themselves from mosquito borne illness.”

 

The virus is NOT transmitted from person-to-person.  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.  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 long-sleeved shirts and long pants when outdoors.

 

The most sensitive indicator of West Nile virus activity is the presence of dead crows.  Timely reporting of dead crows can be made to the West Nile virus toll-free hotline at 1-888-668-0869 or through a website being piloted by Michigan State University that can be accessed through www.michigan.gov/mda and 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. 

 

Additional crows from Wayne, Ingham and Genesee counties will no longer need to be submitted for testing.  Individuals from Wayne, Ingham and Genesee counties are still urged to report the presence of dead crows through either the toll free hotline or website.  Persons should always avoid barehanded contact with dead birds by using gloves or by grabbing the dead crow with a plastic grocery bag. 

 

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.  Based on preliminary evidence, 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, convulsions, muscle weakness 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 now available approved vaccine to help control this disease in horses.  While it has been shown safe for use, effectiveness has not yet been proven.

 

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.

 

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EDITOR'S NOTE:  The Departments of Community Health and Agriculture plan no more releases on bird cases of West Nile virus.  Future updates, including a listing of WNV positive birds and counties, will be posted at http://www.michigan.gov/mda and can be found by clicking on “West Nile Virus,” located along the right “Quick Links” bar.