News of the West Nile virus’ rampant spread across the U.S. continues and after recent rainfall, conditions improve for the mosquito population to flourish.
During 2012, 48 states reported West Nile virus infections in people, birds or mosquitoes and by the end of the summer over 1,118 cases of West Nile virus disease in people – including 41 deaths – had been reported to Centers for Disease Control and Prevention.
The West Nile virus (WNV) belongs to a group of viruses known as flaviviruses, commonly found in Africa, West Asia, Europe, and the Middle East. Flaviviruses are spread by insects, most often mosquitoes. The virus can infect humans, birds, mosquitoes, horses, and other mammals. Since its first appearance in the Western Hemisphere in 1999, WNV has been classified as an emerging infectious disease in the U.S., as it has spread down the East Coast and to many Southern and Midwestern states. WNV occurs in late summer and early fall in temperate zones, but can occur year-round in southern climates.
Symptoms
According to the CDC, WNV infection in humans is rare. Approximately 20 percent of the people who become infected will develop symptoms of WNV. The onset is characterized by mild, flu-like symptoms that usually appear within 3 to 14 days of infection. Common symptoms of WNV include fever, headache, body aches, skin rash on trunk of body, and swollen lymph glands.
A more severe form of the WNV (West Nile encephalitis, West Nile meningitis, or West Nile meningoencephalitis), occurs when the virus crosses the blood-brain barrier. This condition develops in 1 out of every 150 cases. Symptoms may include headache, high fever, neck stiffness, extreme lethargy, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.
Because the symptoms of WNV may resemble other conditions or medical problems, always consult your doctor for a diagnosis.
The Spread
WNV is transmitted to humans through the bite of an infected female mosquito. The mosquitoes acquire the virus through biting infected birds. According to the CDC, WNV is not directly transmitted between humans.
Treatment
Specific treatment is determined by an individual’s doctor based on age, health history, extent of the disease, and tolerance for specific medications or therapies. People who develop the more severe form of the disease (West Nile encephalitis or meningitis), may require more aggressive treatment: hospitalization, intravenous fluids, respiratory support (ventilator), prevention of secondary infections (such as pneumonia, urinary tract infections, etc.), and nursing care.
Prevention
No vaccine currently exists to prevent West Nile virus in humans. The CDC recommends taking the following steps to avoid mosquito bites and WNV:
- Apply insect repellent containing DEET when you’re outdoors. According to the CDC, repellents containing a higher concentration of active ingredient (such as DEET) provide longer-lasting protection. (If you spray your clothing, there’s no need to spray repellent containing DEET on the skin under your clothing.)
- When possible, wear long-sleeved shirts and long pants treated with repellents containing permethrin or DEET since mosquitoes may bite through thin clothing. (Don’t directly apply permethrin-containing repellents to exposed skin.)
- Consider staying indoors at dawn, dusk, and in the early evening – peak hours for mosquito bites.
- Limit the number of places available for mosquitoes to lay their eggs by eliminating standing water sources around your home, such as bird baths.
To maximize your protection from insect repellent, remember:
- Sweating, perspiration, or water may require product reapplication.
- Use enough repellent to cover exposed skin or clothing; heavy application isn’t necessary to achieve protection.
- Don’t apply repellent to cuts, wounds, or irritated skin.
- After returning indoors, wash treated skin with soap and water.
- Don’t spray aerosol or pump products in enclosed areas or directly to your face. Spray your hands and then rub them carefully over the face, avoiding your eyes and mouth.
The American Academy of Pediatrics recommends using caution when applying insect repellent on children. Use products with a low concentration of DEET (30 percent or less) on children between ages 2 and 12. For children younger than age 2, only one application per day of repellent containing DEET is recommended. Also, when using repellent on a child, apply it to your own hands first, then rub onto your child. Avoid children’s eyes and mouth and use the repellent sparingly around their ears.
“Your Health Matters” To read more about WNV, visit www.BRMC-Cares.com and click on the West Nile Virus banner. If you or a loved one displays any of the symptoms of WNV, see your doctor immediately.
About the Author: Narendra Nigalye, MD is Board Certified Internal Medicine and a member of the medical staff at Brownwood Regional Medical Center.
Remember that this information is not intended to replace the advice of your doctor, but rather to increase awareness and help equip patients with information to facilitate conversations with their physician.
