Aedes mosquitoes are invasive species that have spread to many counties in California. First detected in Merced County in 2017, these mosquitoes have now infested every town in the county. They are more than just a nuisance—they can pose a serious public health risk.

Zika virus is transmitted to people primarily through the bite of infected Aedes aegypti mosquitoes (yellow fever mosquitoes) or Aedes albopictus mosquitoes (Asian tiger mosquitoes). These mosquitoes are not native to California. However, since 2011 they have been detected in several California counties. An Aedes mosquito can only transmit Zika virus after it bites a person who has this virus in…