We featured a warning about West Nile Virus on OK Nature Blog awhile back, but due to remarkable increases in cases over the past few weeks, public health officials are again warning Oklahomans to take precautions to prevent mosquito bites. The Oklahoma State Department of Health reminds everyone to use insect repellent when outdoors and to mosquito-proof their home. It’s probably even more important for birders and naturalists to be extra careful because the disease is transmitted from birds to humans by mosquitoes. Senior citizens are also more at risk.
To date, 31 cases of WNV disease have been confirmed in Oklahomans from 10 counties. This number of cases already exceeds the total of WNV disease reports for the previous four years combined. The counties with the highest numbers of cases include Tulsa (9), Oklahoma (6), and Carter (5) County. Most cases have been neuroinvasive WNV disease, which is the most severe form of WNV infection and causes inflammation of the brain and spinal cord. Adults over the age of 50 are at greatest risk of severe neurologic illness and death due to WNV infection.
Public health surveillance indicates that most WNV cases this year have occurred in Oklahomans over 40 years of age with 26 percent occurring among persons 70 to 79 years old. The age range of WNV disease cases is 17 to 90 years. Among persons that have been interviewed regarding their mosquito exposures, 96 percent reported their home county was the likely location of exposure. Activities around the residence, such as relaxing on the patio, doing yard work, or tending the flower beds often are the times when persons are exposed to mosquitoes and WNV.
Illness associated with WNV ranges from no symptoms at all to milder “West Nile Fever” symptoms to serious neurologic disease. Symptoms of West Nile Fever include sudden onset of fever, headache, nausea, dizziness, and muscle weakness. Sometimes swollen lymph glands or a skin rash are also present with West Nile Fever. Symptoms of serious neurologic WNV disease can progress quickly and may include high fever, headache, stiff neck, mental confusion or disorientation, numbness, convulsions, and coma. A polio-type paralysis of an arm or leg may also be caused by WNV. Some of the neurological effects of WNV may be permanent or fatal. Persons should seek medical attention if any of these symptoms develop, especially within two weeks after mosquito bites.
Oklahomans are urged to become “mosquito aware” and take the following precautions to protect themselves against mosquito bites:
- Use an insect repellent containing DEET on exposed skin and clothing when you go outdoors. (Insect repellent with permethrin should be used on clothing only.)
- Place mosquito repellent in a handy and visible location in the home for easy access.
- Repair or install window and door screens to keep mosquitoes out of your home.
- Prevent items such as buckets, cans, flower pots, and tires from holding standing water so mosquitoes don’t have a place to breed.
- Empty, clean and refill your bird baths and pet’s outdoor water bowl daily.
- Clean leaves and debris from rain gutters regularly to ensure they are not clogged.