Invasive Aedes Mosquito Extends Reach in Los Angeles, Orange Counties

The county vector control staff informed Graham Jenkins and his wife late last month that the itchy bites on their ankles were the work of a vicious mosquito that had invaded their Gardena home – and that there was nothing they could do.

“Those little bastards live with us forever now,” Jenkins said.

A couple of bites on the 34-year-old’s wrist recently became infected and took him to the emergency room. After a week of antibiotics, he said he was “almost back to normal” but still wore his watch on the other wrist.

The invasive Aedes mosquito is an aggressive biter with the ability to penetrate clothing and reproduce in water sources as small as a bottle cap. They fly low on the ground and strike during the day, preferring human blood to that of birds or other animals. They often strike several times in quick succession.

Southern California pest experts say not only is the mosquito here to stay, but its range – and season – is increasing.

It is believed that Aedes mosquitoes – which are of three different species – were first brought into Los Angeles County in 2001 in shipments of lucky bamboo from China. But it wasn’t until 2011, when complaints arose in El Monte, that the stubborn insects began to take root.

Since then, the flying bloodsuckers have spread widely across the county and beyond, and are still popping up in new neighborhoods. And when they do, calls from confused – and itchy – residents begin to spike, according to vector control officers.

The mosquitos appeared in Sunland and Sun Valley this year, and even as far north as Santa Clarita and Castaic, and residents have been vocal about their plight, said Mary-Joy Coburn, communications director for Greater LA County’s Vector Control District.

“This is pretty much the first time many of these residents have seen these aggressive mosquitoes,” she said. “So they called us and tried to get more information.”

A map of mosquito density within the district shows a tiny concentration in South El Monte in 2013. By 2020 that presence had increased, saturating almost the entire district on the map.

It’s not just LA County that has seen a meteoric surge in the winged scourge. Areas in the south and north have all reported an increase in “knuckle-biters”.

They can’t fly far, but according to Coburn they are persistent and “smart”. A female mosquito could ride the car and lay her eggs in the city where she got off. Some people unknowingly give away plants that carry mosquito eggs. And they are able to hop fences in the neighbor’s garden.

Orange County recently confirmed the presence of the mosquitoes in every city there.

Laguna Beach – the last holdout – saw its first slump last August, said Kiet Nguyen, a vector ecologist with the Orange County Mosquito and Vector Control District.

They are also invading Northern California and have a migration pattern that is closely adjacent to the 5 Freeway, said Heather Hyland, a public information officer for the Orange County Vector Control District.

The insect season also seems to be widening.

“Our campaign was from June to August, and then you saw relief,” said Hyland, “but that’s no longer the case.” Now they arrive in April and stay until November, she said.

The insects are most prevalent in September and October and defy traditional mosquito perceptions, which peak in summer, according to Levy Sun, director of communications at San Gabriel Valley Mosquito and Vector Control.

“Just like fire season, mosquito season is year-round,” Sun said.

Jason Carter, 30, said the mosquitoes were “treacherous” in San Diego, where he lives.

The other day he was reading in a hammock on his backyard patio when he saw one of the creatures whiz by. He ran in “to escape his anger”. But it was too late. Later he counted five bites.

Some have learned about the ways of the Aedes.

John Gary and his family armed themselves with “lots of devices and drugs and protocols” this year, said the 46-year-old Glendale resident.

Last year, his son Nicholas, 11, struggled to stay awake at night because of itchy bites that showed up as large welts on his ankles and legs. There were so many stains on it that they thought they had bed bugs.

Gary lubricates herself with DEET bug spray before going out, and the family installs a bug zapper in their dining room. They also have chopsticks of bite balm, benadryl, picaridin spray, citronella-infused wristbands, and a syringe-like device for soaking up irritants from insect bites.

Jenkins and his wife Jasmine Chan have also taken measures to combat the pests. They lather themselves up with picaridin, keep fans under their desks, and water their houseplants with minimal moisture to limit their reproduction.

You’re doing everything right, say experts, who say repelling and eliminating even tiny sources of water – where they can multiply – are the best ways to control the mosquitos.

Extinction, at least for now, is not in sight.

Aedes can transmit diseases like chikungunya, dengue, and zika, but they have not been linked to an outbreak in California.

They have also not been linked to a case of the deadly West Nile virus. Meanwhile, their local brothers, the Culex mosquito, have been identified as the source of the deadly virus.

Aedes are viewed by the vector control officers as an “annoying mosquito” and are therefore not of the utmost importance.

Cutting edge technologies in development could bring local relief – but probably not for several years.

California authorities are considering introducing sterile male mosquitoes into the population. The idea is that the male mosquitoes – sterilized by bacteria, gene modification, or X-rays – mate with the females and produce non-viable eggs, which destroys the population.

Sun of the San Gabriel Valley MCVD said many find the idea “tastier” than spraying potentially toxic pesticides. Other cities, including Miami-Dade in Florida, have tested the method in pilot programs.

“What better way to target a mosquito than a male mosquito trying to mate?” He said.

However, Coburn said the tech was “not on the table right now”. Some of the practices are still under review by the Environmental Protection Agency and would require regional adoption to work.

Comments are closed.