West Nile virus (WNV) is an infectious disease that first appeared in the United States in 1999. Infected mosquitoes spread the virus that causes it. People who get WNV usually have no symptoms or mild symptoms. The symptoms include a fever, headache, body aches, skin rash, and swollen lymph glands. They can last a few days to several weeks, and usually go away on their own.
If West Nile virus enters the brain, however, it can be life-threatening. It may cause inflammation of the brain, called encephalitis, or inflammation of the tissue that surrounds the brain and spinal cord, called meningitis. A physical exam, medical history, and laboratory tests can diagnose it.
Older people and those with weakened immune systems are most at risk. There are no specific vaccines or treatments for human WNV disease. The best way to avoid WNV is to prevent mosquito bites:
- Use insect repellent
- Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets or barrels
- Stay indoors between dusk and dawn, when mosquitoes are most active
- Use screens on windows to keep mosquitoes out
- FAQ: West Nile Virus and Dead Birds (Centers for Disease Control and Prevention)
Statistics and Research
- Study of Mosquito Protein Could Lead to Treatments Against Life Threatening Viruses (National Institute of Environmental Health Sciences)