First infected bird of season found
Researchers have positively identified the state's first bird infected with the West Nile Virus (WNV) this year. The blue jay, found in Washtenaw County, was collected earlier this month and tested positive for WNV at Michigan State University's Diagnostic Center for Population and Animal Health.
"Because we cannot predict the impact WNV will have on Michigan again this year, it is crucial that we continue our efforts with virus surveillance, mosquito control activities and public education," says Janet Olszewski, director of the Michigan Department of Community Health (MDCH). "Citizens need to be aware of the potential risk of WNV infection in Michigan, and communities should use surveillance information to target intervention and prevention strategies in areas where WNV activity has been detected."
Late spring typically signals the beginning of the season for mosquito-borne diseases in Michigan, such as WNV. Surveillance activities continue this year as a cooperative partnership involving the Michigan departments of agriculture, community health, environmental quality and natural resources; Michigan State University; and local health departments throughout the state.
Mosquitoes most likely to transmit WNV to humans lay eggs in small collections of stagnant water. Adults can hatch in as short as 10 days in the warmest months of the summer. Mosquitoes become infected with WNV after feeding on sick birds carrying the virus. Within 10 to 14 days, a mosquito can transmit the virus to humans.
In 2004, Michigan experienced a light WNV year, with 16 reported cases and no fatalities. Last year, 255 birds statewide tested positive for the virus.
WNV has been detected in 47 of 48 states in the continental United States and is endemic in most of the country. Michigan can expect to experience WNV infection in birds, mosquitoes, horses, other animals and humans in 2005, but the magnitude of the impact cannot be predicted.
"Preventing exposure to mosquitoes in the months ahead will be important," says Dr. Dean Sienko, MDCH acting chief medical executive. "Since West Nile virus is spread to humans and horses almost exclusively through the bite of an infected mosquito, people need to take measures that reduce the chance of receiving mosquito bites."
Michigan residents are encouraged to:
• Maintain window and door screening to help keep mosquitoes out of buildings;
• Drain puddles in the yard, emptying water from mosquito breeding sites such as buckets, troughs, barrels, old tires or similar sites where mosquitoes lay eggs;
• Avoid being outdoors when mosquitoes are most active (dawn and dusk);
• Wear light-colored, long-sleeved shirts and long pants when outdoors;
• Apply insect repellents that contain the active ingredient DEET to exposed skin or clothing, always following the manufacturer's directions for use. Avoid applying repellent to children less than 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; and
• Report sightings of sick and wild birds and mammals to help officials monitor the risk of WNV to humans, wildlife and domestic animals. For a form that allows rapid reporting visit http://www.michigan.gov/westnilevirus. For those without Internet access, visit local libraries to log on to the site or call 1-888-668-0869 (toll free) to report sightings or for updated information about WNV.
Most people bitten by an infected mosquito show no symptoms of illness; however, some become sick 3-15 days after exposure.
Sienko says about 1-in-5 infected persons will have mild illness with fever, and about one in 150 infected people will become severely ill. Symptoms of encephalitis (inflammation of the brain) and meningitis (inflammation of the spinal cord and brain linings) include stiff neck, stupor, disorientation, coma, tremors, muscle weakness, convulsions and paralysis.