Invasive Mosquitoes Spread In The Bay Area

SANTA CLARA COUNTY, CA — An invasive mosquito known to carry diseases like Zika and yellow fever has been found in more parts of Santa Clara County, triggering community meetings and aggressive plans to eliminate the threat.

According to the Vector Control District, the day-biting Aedes aegypti is known to be in five locations after recently spreading to South San Jose. Earlier confirmations include another area of San Jose near Oak Hill Funeral Home, East San Jose, Gilroy, and a growing "infestation" in Santa Clara.

The invasive insects are a quarter-inch in size, with black and white stripes on the back legs, and feed almost exclusively on humans.

Officials said the expanding detections highlight an urgent need for businesses and residents to proactively eradicate potential breeding grounds.

"The threat posed by Aedes aegypti is growing, and we need everyone to pitch in now to prevent this day-biting mosquito from becoming established in Santa Clara County," said Edgar Nolasco, director of the County of Santa Clara Consumer and Environmental Protection Agency. “In the interest of public health, we need businesses and residents to check their properties for sources of standing water and remove them. And we need the people who live in areas where this non-native mosquito has been found to work together with district staff and allow them to inspect their properties."

According to the Vector Control District, Aedes aegypti mosquitoes are not endemic to the United States and have been known to transmit dengue, chikungunya, Zika and yellow fever. The mosquitoes have been detected in 19 counties throughout California, mostly in the Central Valley and SoCal, and the Los Angeles County Department of Health has reported five cases of dengue fever this year.

The mosquitoes have been detected in four Bay Area counties but have yet to become established, officials said. Among the other locations are Alameda and Contra Costa counties.

Los Angeles County just had its 11th case of Dengue Fever.

"If the day-biting mosquito establishes a permanent population in Santa Clara County, it will not only threaten public health but also affect our quality of life, as these mosquitoes are highly aggressive and active during the day, unlike native mosquito populations, which are most active in the morning and evening, when temperatures are cool," the district said. "These mosquitoes need very little water to lay their eggs, which can last for more than a year in dry conditions, and they often lay them in hard-to-reach places."

Here is where the mosquitoes have been found in Santa Clara County:

• South San Jose: 22 mosquitoes found
• Santa Clara: 172 mosquitoes found
• Gilroy: six mosquitoes found
• East San Jose: 151 mosquitoes found
• San Jose (near Oak Hill Funeral Home & Memorial Park): two mosquitoes found

The county asks residents to examine their properties and dump out even small amounts of standing water. Officials said residents should also clean out bird baths, pet dishes and other containers that could harbor small eggs, which can look like tiny bits of dirt to the naked eye.

The Vector Control District plans to start treating known areas with larvacide spray and may expand to adult mosquito control measures as necessary.

Two community meetings are scheduled for South San Jose and Santa Clara:

South San Jose Community Even

• Baldwin Elementary – Multipurpose Room
• 280 Martinvale Lane, San Jose
• Wednesday, Nov. 6, at 6 p.m.

Santa Clara Community Event

• Wilcox High School – Multipurpose Room
• 3250 Monroe St., Santa Clara
• Tuesday, Nov. 12, at 6:30 p.m.

Here are a few more recommendations to protect against mosquitoes:

• Wear long-sleeve shirts, pants, socks and shoes when mosquitoes are most active.
• Apply insect repellents containing EPA-registered ingredients such as DEET, picaridin, IR3535 or oil of lemon eucalyptus, always following label instructions
• Make sure your window and door screens are in good condition.
• Properly screen rain barrels, cisterns and irrigation drains to prevent mosquito access.
• Fix leaky water faucets and broken sprinkler heads and avoid overwatering lawns and plants.
• Ensure window and door screens are in good condition with no holes or tears and are tight-fitting.
• Make sure the water level of swimming pools is adequate for proper circulation and filtration.

More information about the Aedus egypti mosquito is available on the California Public Department of Health's website.