Two invasive (non-native) mosquito species have recently been found in several California cities (see map below), and there is a potential for them to spread into other areas of California. They are named Aedes aegypti (the yellow fever mosquito) and Aedes albopictus (the Asian tiger mosquito). Unlike most native mosquito species, Aedes aegypti and Aedes albopictus bite during the day. Both species are small black mosquitoes with white stripes on their back and on their legs. They can lay eggs in any small artificial or natural container that holds water.
Aedes aegypti and Aedes albopictus have the potential to transmit several viruses, including dengue, chikungunya, Zika, and yellow fever. None of these viruses are currently known to be transmitted within California, but thousands of people are infected with these viruses in other parts of the world, including in Mexico, Central and South America, the Caribbean, and Asia. The presence of Aedes aegypti and Aedes albopictus mosquitoes in California poses a threat that Zika, dengue, and chikungunya viruses can be transmitted in infested areas from returned infected travelers. Travelers can protect themselves by preventing mosquito bites. When traveling to countries with dengue, chikungunya, or Zika, use insect repellent, wear long sleeves and pants, and stay in places with air conditioning or with window and door screens.