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The Santa Clara County Vector Control District Joins the San Mateo Vector Control District to Fight Aedes aegypti, a New Invasive and Disease Carrying Mosquito Species

Published on: 8/28/2015 8:43 AM
Following the detection of Aedes aegypti (the yellow fever mosquito) in Menlo Park on August 2013, the Santa Clara County Vector Control District (SCCVCD), in coordination with the San Mateo Mosquito and Vector Control District (SMMVCD), has started a monitoring program to detect and treat any invasion of this mosquito species.
This mosquito is not native to California and is an efficient carrier of viral diseases such as dengue, yellow fever, and chikungunya. Aedes aegypti is a small, dark mosquito with white markings and banded legs. It may be active around dusk but bites most often during the day and readily enters homes.
Aedes aegypti joins Aedes albopictus (the Asian Tiger mosquito) as a new vector and public health threat in California.  Just two years ago, the Aedes albopictus was found in the cities of El Monte and South El Monte in Los Angeles County.  The day-biting Aedes albopictus is characterized by its small size and the black and white stripes across its body and legs. This mosquito also can transmit various vector-borne diseases such as dengue and chikungunya. Since its detection in 2011, Southern California mosquito control agencies have been working aggressively to control and eradicate this invasive species.
These two species are “container-breeders” and require very little water to lay eggs and breed. Females will lay individual eggs just above the water in buckets, saucers under flower pots, and even trash.  They will also lay eggs in any plants that hold water such as inside tree holes, bamboo, and flowering plants like bromeliads. When re-flooded with water, the eggs hatch and larvae emerge, maturing to biting adults in 7 to 12 days.
Asian Tiger Mosquito

The adult Aedes aegypti (above left) is brownish with a pattern on the back resembling a guitar or violin.  The adult Aedes albopictus (above right) is black with a solid white stripe running down the mosquito “back” or thorax. Other day-biting mosquitoes in our county, such as the Western Treehole and Summer Salt Marsh Mosquitoes, lack these distinctive markings.
At this time, infestation of the 2 species in California is challenging mosquito control efforts by local districts. The SCCVCD, in the past, has successfully eradicated two introductions of Aedes albopictus (the Asian Tiger Mosquito) in our county. However, this time, the quick spread of these two mosquito species in California is making it more difficult to control. Recent and ongoing detections of Aedes aegypti (Yellow Fever Mosquito) in San Mateo areas has placed our county at greater risk of a resulting invasion. For this reason, SSC residents' awareness on the prevention is very important.
Please take the following measures for the prevention and control of container-breeding mosquitoes around your house:
  • Dump and drain all standing water around your home.
  • Discard or store inside all unused containers, cans, buckets, or old tires.
  • Remove all water dishes from beneath potted plants.
  • Add sand or drill drain holes in the bottom of all plant pots.
  • Throw away trash in your yard including wrappers and bags.
  • Clean out rain gutters and lawn drains to ensure water does not collect.
  • Make sure rain barrels are completely sealed to prevent mosquitoes from entering.
  • Empty bird baths and small fountains completely or clean them thoroughly every 3 days.
  • Request free mosquitofish from the district.
  • Report mosquito sightings, daytime bites, or breeding sources immediately!

Some personal protection measures you can take are:

  • Dress appropriately by wearing long sleeves and pants when outside.
  • Defend against mosquitoes by using DEET or other EPA-registered repellents.
  • Be sure window and door screens are in good repair to prevent mosquitoes from entering the home.

You can contact us here to receive more information or to request a free inspection.