FOR RELEASE: August 26, 2002
CONTACT: Pamela Williams
405/271-5601

State Health Officials Announce Two Probable Human Cases of West Nile Virus

The Oklahoma State Department of Health announced today that it is waiting on final confirmation of two probable human cases of West Nile virus disease by the Centers for Disease Control and Prevention (CDC). The cases involve a 69-year-old Washington County man, who may have acquired the disease out of state, as well as a 12-year-old Tulsa County boy.

Both tested presumptively positive in tests conducted by the Oklahoma State Department of Health’s Public Health Laboratory. The specimens were sent for confirmatory testing to the CDC.

Both individuals developed encephalitis and were hospitalized. After receiving supportive treatment, both are now home recovering from their illness.

“With the rapid spread of West Nile virus in our bird and horse populations, human cases in Oklahoma were not unexpected,” said State Health Commissioner Dr. Leslie Beitsch. “We are pleased that these individuals are recovering from their illnesses and appear to be doing well.”

West Nile virus is spread to humans by infected mosquitoes. Most persons who become ill with West Nile virus after being bit by an infected mosquito have no symptoms or only mild symptoms of illness such as fever, headache, backache, and muscle weakness lasting two to six days. Less than one percent will develop the more serious complications of encephalitis.

In order to protect themselves and their family members from West Nile virus, Beitsch urged the public to limit outside activity at dusk and dawn when mosquitoes are actively feeding.

“If you must be outdoors during early evening or early morning hours, wear clothing with long sleeves and long pants, and apply an insect repellent containing DEET to exposed skin and clothing. Do not apply to the skin of children less than 2 years of age, however. Repellents containing less than 30 percent are advised; those with higher concentrations do not mean they will work better, just that they may last longer,” he said.

Health officials also advise reducing mosquito-breeding locations in their yards. Empty and refill birdbaths and pet water daily. Empty buckets, tarps, wading pools, old tires, and any other containers that may hold stagnant water where mosquitoes can breed. Clean out roof gutters and trim grass and weeds regularly to control the mosquito population in the yard.

The current West Nile virus surveillance and education process in Oklahoma involves a coordinated effort among many resources:

• Human Surveillance. The Oklahoma State Department of Health works closely with physicians, infection control practitioners, hospital epidemiologists, local health departments and laboratory directors to identify possible cases of human West Nile virus disease in Oklahoma. This active surveillance will enhance the rapid detection of possible cases. The process involves medical facilities submitting blood samples for testing to the Oklahoma State Department of Health Public Health Laboratory. Positive Oklahoma laboratory results are confirmed by the CDC prior to releasing public information to ensure accuracy.
• Bird Surveillance. The most sensitive indicator of West Nile virus activity in an area is the presence of dead crows, blue jays and raptors (hawks, owls and eagles). Crows are very susceptible to infection with West Nile virus and will die within two to three weeks of infection. The Oklahoma Animal Disease Diagnostic Laboratory at Oklahoma State University handles testing of birds in Oklahoma. Persons who find these freshly dead birds can call a toll-free number, 1-800-990-CROW (2769) during regular business hours to report their sightings. Tulsa County residents should call another special hotline number, 918-595-4200, to report sightings in their county. Callers will be asked to describe the bird and where it was found. If the bird is suitable for testing, callers will be asked to transport the bird to the nearest drop-off point.
• Horse Surveillance. The Oklahoma Department of Agriculture works closely with private veterinarians 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. The agriculture department handles all testing of horses for Oklahoma.
• Mosquito Surveillance. The Oklahoma State University Department of Entomology handles inquiries about the Oklahoma mosquito-trapping program and mosquito-related questions. In addition, the University of Oklahoma Health Sciences Center Department of Microbiology and Immunology is working with the Oklahoma State Department of Health, the Oklahoma Biological Survey, the U.S. Army at Fort Sill, and the U.S. Air Force at Tinker Air Force Base to screen mosquitoes for the presence of West Nile virus. Six positive mosquito pools were confirmed last week in Comanche County.
• Health Care Provider Education Efforts. Efforts to educate the medical community about the West Nile virus continue with written and verbal communications to assist neurologists, infectious disease doctors and emergency room providers to identify and treat individuals.
• The Association of Central Oklahoma Governments. Efforts to educate the general community about West Nile virus prevention activities are coordinated through a series of meetings and briefings on what cities can do to help control the mosquito populations in their areas.

As of August 22, 71 birds in 16 counties in Oklahoma have tested positive for West Nile virus. Counties with multiple bird cases include Tulsa (19), Wagoner (15), Ottawa (11), Oklahoma (7), Pittsburg (3), Cleveland (3), Jackson (2), Muskogee (2), and Payne (2). Carter, Logan, Okmulgee, Garfield, Mayes, Haskell, and Rogers counties have each been the origin of one West Nile- positive bird. Since testing resumed in April 2002, 745 birds have been submitted for testing in Oklahoma. (For numbers of birds tested by county, see charts on the Oklahoma State Department of Health Web site at http://www.health.state.ok.us/program/cdd/ow/results.html.)

###