EEE, commonly called "sleeping sickness," is caused by a virus found in wild birds. Mosquitoes that have fed on birds carrying the EEE virus can transmit the disease to horses and humans. Birds are able to harbor the virus without becoming acutely ill, thereby serving as a reservoir for EEE. Horses do not develop high enough levels of the EEE virus in their blood to be contagious to other animals or humans.

"Even though EEE has not yet been detected in any Kalamazoo County mosquitoes, people should be proactive and take reasonable precautions to avoid the risk of EEE by preventing mosquito exposure and by taking necessary steps to protect their horses," Wyant said.

In horses, clinical signs of EEE include fever, progressive muscle incoordination, paralysis, blindness and inability to rise. The fatality rate can be as high as 95 percent.

According to State Epidemiologist Dr. Matthew Boulton, human EEE infection is rare in Michigan but can be serious when it does occur. The last human case of EEE in Michigan was in 1997 and resulted in a fatality.

"Most cases of EEE in humans do not cause any symptoms. However, symptoms can be severe when they occur and include: headache, high fever, fatigue, muscle ache, stiff neck, tremors, and confusion," Boulton said. "In acute cases, inflammation of the brain (encephalitis) occurs, possibly leading to convulsions, coma or even death."

A vaccine is available to prevent EEE in horses, but vaccination is neither readily available or practical for routine human use. Horse owners should contact their veterinarian to discuss vaccination against EEE. Veterinarians must report all suspect EEE cases to MDA's Animal Industry Division at 517-373-1077. Physicians should immediately report any suspect human cases to their local health department.

There are many ways people can reduce their risk of mosquito bites. They include:

• Applying insect repellent that contains the active ingredient DEET to exposed skin. Always follow the manufacturer's directions for use.
• Spraying clothing with repellents containing permethrin or DEET because mosquitoes may bite through thin clothing. Again, follow the manufacturer's directions for use. Vitamin B and "ultrasonic" devices are not effective in preventing mosquito bites.
• Avoiding applying repellent to children under 2 years of age, and to the hands of older children because repellents may irritate the eyes and mouth.
• Maintaining window and door screening to keep mosquitoes out of buildings.
• Draining standing water in the yard. Emptying water from mosquito breeding sites, such as flower pots, pet bowls, clogged rain gutters, swimming pool covers, discarded tires, bird baths, buckets, barrels, cans and similar sites in which mosquitoes can lay eggs.
• Wearing long-sleeved shirts and long pants when outdoors.
• Avoiding whenever possible outdoor activities at dawn and dusk when mosquitoes are most likely to be feeding.

Earlier this summer, a single mosquito from Tuscola County also tested positive for the EEE virus. While a reservoir for the EEE disease may exist, the mosquito type was identified as one that is not a threat to humans.

Michigan has an active EEE surveillance program in place that involves MDA, the Michigan Departments of Community Health and Natural Resources, Michigan State University, local health departments, private veterinary practices, and four county wide mosquito control programs. This program traps and tests mosquitoes, identifies and tests wild bird flocks, identifies and confirms EEE horse cases, and monitors suspect human cases.

This news release can also be viewed at www.mda.state.mi.us. 

SOURCE: Michigan Department of Agriculture

WEB SITE: http://www.mda.state.mi.us/