Invasive Mosquito Species Found in Citrus Heights

Citrus Heights, CA (MPG)  |  Story by Shaunna Boyd

CITRUS HEIGHTS, CA (MPG) - An aggressive, invasive species of mosquito has been detected within the City of Citrus Heights. The species is called Aedes aegypti, or the Yellow Fever Mosquito. Gary Goodman, District Manager of the Sacramento-Yolo Mosquito and Vector Control District, spoke at the September 26 Citrus Heights City Council meeting to provide an overview of the situation. 

Goodman explained that Aedes aegypti are small, dark mosquitoes with banded legs and violin-shaped markings on their backs. They prefer to live in urban areas both indoors and outdoors, and they are aggressive day biters that prefer to bite humans. “Typically, this species is found in Mexico and Central America,” said Goodman, “but it’s started to slowly, over the last 10 years, make its way into California.” Goodman explained that there are established populations in Southern California and Fresno, and just this year they have been found in Stanislaus County, San Joaquin County, Placer County, and now Sacramento County.

On August 28, 2019, the District was informed of Aedes aegypti detection by Placer County, just 700 feet north of the Citrus Heights border, in an unincorporated area of Placer County outside of Roseville.

The District began a door-to-door campaign in Citrus Heights on August 29. “Mosquitos look for CO2 as you breathe out,” said Goodman, “that’s how they find hosts.” So, the District visited numerous local properties, setting traps that release CO2 to attract and capture the mosquitoes.

Goodman said a cluster of detections were centered around the Twin Oaks Blvd. area between Auburn Blvd. and Mariposa Ave.: “We have done extensive trapping in and around that area hoping to be able to contain it.”

After detecting the invasive species, the District began implementing larval control treatments and adult control treatments to try to slow the infestation. A total of 470 traps were set to assess the scope of the infestation, and a second area of infestation was detected on September 19. The second area is on the west side of I-80, just north of Antelope Rd. between I-80 and the railroad tracks.

Goodman said the infestation is currently centered on those two neighborhoods, and the District is working hard to control the population. The District is seeing reductions when trapping the same areas again, “so control efforts are working,” said Goodman.

The District will continue trapping through October until the mosquitoes begin hibernating when the weather cools off. Goodman said, “The eggs survive for months. Eggs laid now will not hatch until springtime.”

Goodman said, “They just need a very small amount of water to breed. … A bottle cap filled with water can breed these mosquitoes, which makes them very difficult to try and control.” And this particular species doesn’t lay all their eggs in one place — instead depositing eggs in multiple water sources. “We don’t want it to become established here,” said Goodman, “they’re voracious, they’re very aggressive.” He explained that they are very difficult to control, very bothersome, and capable of transmitting debilitating diseases including zika, dengue fever, and chikungunya.

There have not been any reports of illnesses yet, but the concern is that people who travel out of the country can bring exotic diseases back with them, and a population of Aedes aegypti increases the risk of transmission. Which is why the District is trying to access as many properties as possible. They have been conducting site visits on the weekends to increase access rates, and they have implemented a public outreach campaign: visiting neighborhood associations, launching targeted social media ads, and distributing door hangers and postcards to local residents.

Goodman explained that it is only the female mosquitoes that bite, while the males just feed on nectar: “Females are looking for the protein in your blood so they can produce their eggs.” So, the District is considering obtaining males infected with bacteria that renders them sterile. The sterilized males can then be released into the local population where they find and mate with local females. The mating results in eggs that are not viable and do not hatch. Fewer hatched eggs results in fewer insects, and this process can continue until the number of mosquitoes is low enough to reduce their threat. Goodman said this technique may be used in the spring of 2020 to “suppress the population and hopefully, potentially eradicate these mosquitoes from our area.”

The public is encouraged to report day-biting mosquitos, drain water on their properties, and discard unwanted items that can collect water. To report mosquito infestations or for more information, call 800-429-1022 or visit www.fightthebite.net.