Michigan Department of Community Health Announces Probable Human Cases of West Nile Virus
August 16, 2002
Michigan Department of Community Health Chief Medical Executive, David R. Johnson M.D., today announced two probable human cases of West Nile virus. Laboratory samples have been sent to the Centers for Disease Control and Prevention for confirmatory testing.
The first case involves an 82 year-old male from Southeast Michigan who was hospitalized and has been released in good condition. The second involves a 63 year-old male from Southeast Michigan who is currently hospitalized and appears to be improving.
"We are encouraged that both of these gentlemen appear to be recovering and we will continue to work with health care providers throughout Michigan to quickly identify any other potential human cases, said Dr. Johnson. "The most important thing a person can do to protect themselves from West Nile virus is to follow the common-sense precautions to minimize exposure to mosquitoes.
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. Less than one percent of mosquitoes are infected. Health authorities believe about one in five infected persons will have mild illness with fever, headache and body aches, sometimes with skin rash and swollen lymph glands. Only about one in 150 people infected with West Nile virus will have more serious illnesses of encephalitis and/or meningitis, and these are more likely to be seen in older persons.
"Only individuals with a fever and signs of encephalitis and/or meningitis should be tested for West Nile virus, said Dr. Johnson. Symptoms of these conditions may include headache, high fever, stiff neck, stupor, disorientation, coma, tremors, muscle weakness, convulsions and paralysis.
West Nile virus is spread to humans only by mosquitoes and is NOT transmitted from person-to-person or from crows to people. People cannot get it from touching or kissing others who have 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.
The most sensitive indicator of West Nile virus activity is the presence of dead crows. Citizens are asked to report dead crow sightings to the West Nile virus toll-free hotline at 1-888-668-0869 or through a website at 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.
There is no need for individuals to panic if they find a dead crow. If the bird is found in a county where West Nile has already been detected and has been reported via the toll-free hotline or Internet, it can 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 43 counties--Allegan, Barry, Bay, Benzie, Berrien, Branch, Calhoun, Cass, Charlevoix, Cheboygan, Clinton, Eaton, Genesee, Grand Traverse, Gratiot, Huron, Ingham, Ionia, Jackson, Kalamazoo, Kent, Lapeer, Lenawee, Macomb, Midland, Monroe, Montmorency, Muskegon, Newaygo, Oakland, Ogemaw, Ontonagon, Oscoda, Ottawa, Saginaw, St. Clair, St. Joseph, Shiawassee, Tuscola, Van Buren, Washtenaw, Wayne and Wexford--where West Nile has been detected. Persons in these counties are asked to report the presence of dead crows through either the toll free hotline or website.
The Department of Agriculture has announced three probable cases of West Nile virus in horses in Washtenaw, Emmet and Gratiot counties. The horses are currently being treated. Horse owners are encouraged to follow prevention tips for horses including:
-- 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.
-- 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.
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 mosquito's salivary glands become
infected and they 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.
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. These surveillance activities include:
Human surveillance. The Department of Community Health will continue to work closely with physicians, infection control practitioners, hospital epidemiologists, local health departments and laboratory directors to identify possible cases of human disease in Michigan. This active surveillance will enhance rapid detection of possible cases.
Surveillance of crows. The most sensitive indicator of West Nile virus activity in an area is the presence of dead crows. Crows are very susceptible to infection with West Nile virus and will die within two to three weeks of infection. Timely reporting of dead crows can be made to the West Nile Virus toll-free hotline at 1-888-668-0869 or www.michigan.gov/mda and by clicking on "West Nile Virus and "2002 Specimen Collection and Submission Instructions.
Surveillance of horses. The Department of Agriculture will continue to work closely with private veterinarians, Michigan State University and horse owners to detect cases of encephalitis including West Nile virus in horses. If a horse is infected with the virus, there is no risk for that horse to directly transmit the virus to other animals or humans.
Mosquito surveillance. The Michigan Department of Agriculture, in partnership with other state and local agencies, coordinates educational opportunities to provide information for local health departments regarding source reduction, personal protection and mosquito collection and identification.
Epidemiology and Laboratory efforts. The Michigan Department of Community Health has increased epidemiology and laboratory capacity to conduct surveillance for West Nile virus. The laboratory has Biosafety Level 3 facilities and appropriate training from the Centers for Disease Control and Prevention to enhance existing capacity to detect West Nile and other mosquito-borne viruses.
Health Care Provider education. Efforts to educate the medical community about the West Nile virus will continue to assist neurologists, infectious disease doctors and emergency room providers to identify and treat individuals.
More information on West Nile virus can be found at http://www.michigan.gov/mda, http://www.cdc.gov. The most recent listing of counties where West Nile virus has been detected in birds can be found at http://www.michigan.gov/mda and by clicking on "West Nile Virus, located along the right "Quick Links bar.