State Public Health Officer Warns of Invasive Mosquitoes Detected in California
Date: 10/14/2015
Number: 15-075
Contact: Anita Gore, Orville Thomas (916) 440 7259
SACRAMENTO ā California Department of Public Health (CDPH) Director and State Public Health Officer Dr. Karen Smith is warning Californians to protect themselves from two invasive mosquito species recently found in California. Both species can transmit infectious diseases, such as dengue fever, chikungunya and yellow fever. This warning comes as two more counties are added to the list of counties where Aedes aegypti (the yellow fever mosquito) and Aedes albopictus (the Asian tiger mosquito) have been detected.
āIt is important to know these species of mosquitoes because they are not what weāre used to in California, and they can transmit diseases such as dengue fever, chikungunya and yellow fever,ā Dr. Smith said. āWhile the risk is still low in California, infected travelers coming back to California can transmit these viruses to mosquitoes that bite them. This can lead to additional people becoming infected if they are then bitten by those mosquitoes.ā
In September 2015, Aedes aegypti was
detected for the first time in San Bernardino and Riverside Counties. Since 2013, when this species was first discovered in Madera, Fresno and San Mateo counties, it has been found in Tulare, Kern, Los Angeles, San Diego, Imperial, Orange, and Alameda counties. Also in September, Aedes albopictus, was detected in Kern and San Diego counties and has expanded in regions of Los Angeles County.
Neither of these mosquitoes is native to California. They are known for their black-and-white stripes, biting people during the middle of the day and readily entering buildings. The more-familiar Culex mosquitoes bite primarily at dusk and dawn.
āThere is no vaccine or treatment for chikungunya or dengue fever. To prevent these diseases from becoming established in California, it is important for everyone to take steps to keep these mosquitoes from spreadingā Dr. Smith said. āIf you notice that you are being bitten by mosquitoes during the day, or notice black-and-white striped mosquitoes, call your local mosquito and vector control agency. Your participation in mosquito surveillance greatly aids in efforts to detect new infestations.ā
To prevent mosquito-borne illnesses present in California, such as West Nile virus disease, or abroad, such as chikungunya and dengue, Dr. Smith offers the following tips:
- Apply mosquito repellents containing DEET, picaridin, IR3535, and/or oil of lemon eucalyptus to your skin and clothing.
- Wear long sleeve shirts, long pants, socks and shoes when mosquitoes are most active.
- Use air conditioning, and keep mosquitoes from getting into your home by having intact window and door screens.
- Eliminate potential mosquito-breeding sources, such as water-filled containers, from around your home and where you work. Drain water that may have collected under potted plants, in bird baths and discarded tires. Check your rain gutters to make sure they arenāt holding water, and clean pet water-dishes weekly.
Aedes aegypti mosquitoes can lay eggs in containers holding as little as a teaspoon of water, and eggs, which are laid just above the water line, can survive dry conditions for months. This is why it is important to dump, drain, or eliminate unnecessary sources of standing water around your home and scrub containers to dislodge eggs.
If you travel to Mexico or other countries in Latin America, it is especially important to be aware of Aedes mosquitoes and the diseases that they can carry. This year, Mexico has had a dramatic increase in the number of chikungunya cases. So far, about one-third of the 120 chikungunya cases imported into California were contracted in Mexico, with 91 percent of cases coming from Latin America. Sixty-nine imported cases of dengue have been reported in California this year.
Aedes aegypti (click for a full-size image):
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