West Nile Virus (WNV) is a mosquito-borne disease that was originally found in Africa, and as of 1999 has moved to the United States. Approximately 80% of people do not develop any symptoms, however about 1 in 5 will get flu-like symptoms that last for a few days, with fatigue and weakness that can last for weeks or months. In a very small percentage of people, <1%, severe neurological illness, such as encephalitis or meningitis (inflammation of the brain or surrounding tissue) may occur. They may last several weeks or become permanent, however this happens in roughly 1 in every 150 people. Animals are also susceptible to WNV, including dogs and cats, but especially horses. To learn more about WNV and horses click here

The main way that people contract WNV is a bite from infected mosquitos. WNV cannot spread through touching.

There are three main ways to reduce the risk of being infected by WNV:

  • Use insect repellent: DEET, picaradin or oil of lemon eucalyptus is recommended. Click here for more information.
  • Protect yourself most DAWN and DUSK: mosquitoes are more likely to bite during early morning and evening, so make sure you wear proper clothing and repellent if outside during these times.
  • Drain standing water: mosquitoes lay eggs on standing water, therefore it is important to eliminate or drain all standing water sources around homes and properties.

Currently, there is no vaccine for WNV; the best method of not contracting the disease is to prevent contact with mosquitoes using the above methods. Please refer to our Home and Garden Maintenance Checklist to learn more on how to prevent mosquitoes. 

Please refer to our Frequently Asked Questions for more information, or contact us via phone at (530) 265-1222 or email at Env.Health@co.nevada.ca.us