Michigan Department of Community Health Announces Additional Probable Human Cases of West Nile Virus

August 22, 2002

 

Michigan Department of Community Health Chief Medical Executive, David R. Johnson M.D., today announced two additional probable human cases of West Nile virus disease, bringing the total number of probable cases in Michigan to four.  Confirmatory testing by the Centers for Disease Control and Prevention continues to be conducted on the first two cases, with results expected by early next week. 

 

The previous cases involved an 82 year-old male from Oakland County, who was hospitalized and later released in good condition, and a 63 year-old man from Oakland County, who has now been discharged from the hospital and continues recovering.  The third case is a 44 year-old woman from Bay County with pre-existing health conditions, who is still hospitalized but improving.  The fourth case is a nine month-old boy from Oakland County.  He was hospitalized for several days then released, and is expected to fully recover.

 

"We are very pleased that all four of these individuals seem to be doing well, said Dr. Johnson.  "The experience in this and other countries clearly indicates that older persons and those with weakened immune systems are at greater risk for serious disease once infected with West Nile virus.  That a infant in our state appears to have contracted West Nile virus disease is unique, and reinforces the need for people of all ages to minimize exposure to mosquitoes in common sense ways.
 
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.  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 the more serious illnesses of encephalitis and/or meningitis.

 

"Only individuals with fever and signs of encephalitis and/or meningitis should be tested for West Nile virus, said Dr. Johnson.  Symptoms of encephalitis (inflammation of the brain) and meningitis (inflammation of spinal cord and brain linings) include severe headache, 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, horses to people 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 47 counties--Allegan, Barry, Bay, Benzie, Berrien, Branch, Calhoun, Cass, Charlevoix, Cheboygan, Clinton, Eaton, Genesee, Grand Traverse, Gratiot, Hillsdale, Huron, Ingham, Ionia, Jackson, Kalamazoo, Kent, Lapeer, Lenawee, Livingston, Macomb, Manistee, Mason, 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.

 

There are three probable cases of West Nile virus in horses in Emmet, Gratiot and Washtenaw counties.  The horses are currently being treated.  Horse owners are encouraged to:
-- Consult with a local veterinarian about using the vaccine to help control this disease in horses.  It has been shown safe for use, and is expected to prove to be effective in studies.
-- Use approved insect repellants to protect horses.
-- Place 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.  Once in the animal or human, the virus multiples and may cause disease, but in most cases will be cleared without bringing on symptoms. 

 

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.