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Mosquito-borne Illnesses

Some mosquitoes carry diseases that infect people when they bite us. The diseases can vary by species – there are different kinds of mosquito – and by region.

In Contra Costa County, the only disease that mosquitoes are known to give humans is West Nile Virus.

The best way to avoid mosquito-borne illnesses is to avoid bites.

  • Use insect repellant
  • Cover up – wear long-sleeved shirts and pants, especially at dawn and dusk
  • Use screens on windows or doors when it gets warm, or just use air conditioning

Contra Costa residents can also help to reduce the local mosquito population.

  • Keep mosquitoes from breeding in your home or garden
  • Report neglected (green) swimming pools, ponds or troughs of stagnant water
  • Get help if you notice unusual mosquito activity

The Mosquito & Vector Control District offers free services and advice about mosquitoes at or 925-771-6196.

Dead Birds