Warm Weather Helps Prolong West Nile Virus Risk

Oct 23, 2017

Summer may be over, but continued warm weather means that mosquitoes are still active. So far this year, 361 cases of the mosquito-borne illness West Nile Virus (WNV) have been reported* in 23 California counties from Imperial to Shasta. Sadly, 18 of these cases resulted in death. The disease is most serious in children, people with weakened immune systems, and the elderly.

Mosquitoes that can transmit WNV breed in aquatic environments like ponds or other sources of stagnant water such as roof gutters, bird baths, and swimming pools.

You can minimize mosquito habitat in your landscape by:

  • Cleaning rain gutters and downspouts to remove debris.
  • Sealing rain barrels. Keep all filters and prefilters clean and free of moisture-retaining debris and inspect regularly for leaks.
  • Maintaining quality in swimming pools with chemical treatments. Cover or drain water from plastic pools when not in use.
  • Turning over any unused garden pots, children's toys, and other objects so they don't hold water.

While working outside, be sure to wear long-sleeved shirts, pants, socks, and a hat when mosquitoes are present. Use insect repellents that contain DEET, picardin, or oil of lemon eucalyptus and reapply according to the label instructions.

To read more about managing mosquitoes, visit the UC IPM Mosquitoes website. For information in Spanish, read our Quick Tip. (Para información en español, lea el Nota Breva: Mosquitos.) 

*To see which California counties have reported cases of WNV, visit WestNile.ca.gov