Michigan Farm Animals Susceptible to Mosquito-Borne Diseases

Health officials encourage taking precautions

September 12, 2007 -- LANSING - The Michigan Departments of Community Health (MDCH) and Agriculture (MDA) today received confirmation from the Michigan State University (MSU) Diagnostic Center for Population and Animal Health (DCPAH) that a yearling Quarter Horse from Cass County tested positive for the Mosquito-borne disease, Eastern Equine Encephalitis (EEE). The young stallion was demonstrating neurological signs associated with EEE and was humanely euthanized. This is the second case of EEE in a Michigan horse this year.

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Five emus on a farm in Berrien County, approximately 20 miles from the Cass County horse, also died from EEE. The emus were penned in an area that had a tremendous amount of mosquitoes. Four turkeys recently died from West Nile Virus (WNV) in Cass County as well.

“Michigan residents need to know the risks associated with mosquito-borne illnesses, which is why we are encouraging citizens to observe several common sense steps to limit exposure to mosquitoes,” said Janet Olszewski, MDCH director. “One bite from an infected mosquito can lead to a severe--and possibly life-altering--illness. Prevention is the key to protection.”

“It’s imperative that people take every precaution possible to prevent mosquito borne disease exposure for themselves and their livestock,” said Dr. Steven Halstead, state veterinarian. “A simple vaccination will protect your animal from these often fatal illnesses, and routine measures to reduce mosquito exposure and eliminate mosquito habitat around the home and farm will help protect people, horses, and other livestock.”

EEE and WNV are both caused by viruses found in wild birds. Mosquitoes that feed on birds infected with EEE or WNV can transmit the disease to humans, horses, and other birds. Some birds are able to harbor the WNV or EEE viruses without becoming acutely ill, thereby serving as reservoirs for the disease. Horses do not develop high enough levels of these viruses in their blood to be contagious to other animals or humans. Because of the high mortality rate for horses and humans, EEE is regarded as one of the most serious mosquito-borne diseases in the United States.

Tips for preventing mosquito-borne diseases include:

* Avoid mosquito bites: Use insect repellent when outdoors, especially from dusk to dawn. Look for EPA-labeled products containing active ingredients, such as DEET, Picaridin (KBR3023), or oil of lemon eucalyptus (p-menthane 3,8-diol). Apply more repellent, according to label instructions, if mosquitoes start to bite.
* Mosquito-proof homes: Fix or install window and door screens and cover or eliminate empty containers with standing water where mosquitoes can lay eggs.
* Vaccinate your horses: Commercially available licensed vaccines against EEE and WNV are recommended for all horses in the U.S. Horses should be vaccinated annually, and in areas where WNV is widespread in mosquitoes and when local conditions contribute to disease risk, boosters should be considered in consultation with your local veterinarian. It’s not too late this year to vaccinate your horses.
o Use approved insect repellants to protect horses.
o If possible, put horses in stables, stalls, or barns during the prime mosquito exposure hours of dusk and dawn.
o Eliminate standing water and drain water troughs, and empty buckets at least weekly.
* Help your community: Report dead birds to your local health department to help track WNV and support community-based
mosquito control programs.

Seasonal activity varies from year to year, but mosquitoes carrying EEE or WNV remain a threat. EEE has spread to Michigan from the east coast of the U.S. and WNV has spread across the U.S., from coast to coast, with new cases being reported daily. Since WNV activity often does not peak until September, more cases are expected.

For more information on the human health impact of EEE, please visit the Centers for Disease Control and Prevention (CDC) web site.

For more information about EEE or WNV in horses, consult your local veterinarian or contact MDA’s Animal Industry Division at 517-373-1077; or visit the MDA Web site at: www.michigan.gov/mda for EEE and www.michigan.gov/emergingdiseases for WNV.

Source: MDCH