Public Health Topics
Mosquito-Borne Viruses


Mosquito bites can be more than just annoying and itchy. Some types of mosquitoes, both in the United States and around the world, spread viruses that can cause disease.

Mosquitoes bite during the day and night, live indoors and outdoors, and search for warm places as temperatures begin to drop. Some will hibernate in enclosed spaces, garages, sheds, and under (or inside) homes to survive cold temperatures.

West Nile Virus
West Nile Virus is in Los Angeles County and can cause severe illness, even death. Everyone is at risk of West Nile Virus infection, but people over 50 and those with existing health conditions are most at risk of serious illness and long-term health problems. To learn more about West Nile Virus, including transmission and symptoms, visit the CDC.

Zika Virus
Zika Virus can cause serious birth defects. Zika is spreading in Mexico, Central and South America, and the Caribbean. If you’re pregnant or plan to become pregnant, protect yourself from mosquito bites. Wait to travel to these areas until after your baby is born. To learn more about Zika Virus, including transmission and symptoms, visit the CDC.

The most effective way to avoid getting sick from mosquito-borne viruses when at home and during travel is to prevent mosquito bites.

  • Use Environmental Protection Agency-registered insect repellents that contain DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone
  • Wear long-sleeved shirts and long pants
  • Use screens on windows and doors to keep mosquitoes outside
  • Remove standing water from items inside and outside your home like planters and trash cans
  • Learn about destination-specific health risks and recommendations before you travel by visiting the CDC

Additional Resources

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