Most know them as the annoying ankle biters.

Sumiko De La Vega knows them as Aedes aegypti.

The annoying mini-mosquitos bit all day long.

They’ve been in Stockton since 2019 and have spread to Manteca, Ripon, Tracy, Escalon, Lathrop, Mountain House, and Lodi.

The mosquito is notorious for the spread of yellow fever as well as chikungunya, Zika, and dengue.

The good news — thanks in part to the efforts of the San Joaquin County Mosquito & Vector Control District that Manteca resident De La Vega works for — there have been no local generated cases of diseases caused so far by the mosquito.

There have, however, been reported travel related cases of dengue in San Joaquin County with 13 in 2024.

Unlike most of the other 18 mosquito species — invasive and natural — found in San Joaquin County, the ankle biters travel no more than 200 to 300 feet from where they are hatched as opposed to between 1 and 10 miles for other species.

The eggs also have a longer lifespan able to survive up a year before hatching after being laid in mud that then dries.

As such, tackling the annoying ankle biters is a matter of — for want of a better description — good “yard and garden hygiene.”

Even a bottle cap turned upside down can be a breeding ground for mosquitos after it sits for several days with water in it. A bottle cap can hold enough larvae that looks like microscopic specks of black dirt to generate 50 mosquitoes.

All sorts of yard items can be vessels for breeding the ankle biters.

They run the gamut from old tires, children’s toys, plant saucers, fountains, gutters that aren’t kept clean, birdbaths with infrequent water changes, and neglected pools to anything capable of holding even a small amount of standing water for multiple days.

In making requested inspection of residential properties with infestations of the ankle biters, district personnel discovered that yard drains for lawns and patios are ideal breeding grounds for the mosquitos given they harbor small pools of standing water.

The best fix is the placement of screening material over the drain cover.

The typical lifecycle for the ankle biters is 5 to 10 days in warm weather as opposed to 2 to 3 weeks for most other mosquitos.

After working with the district for 16 years as a lab assistant, it is now De La Vega’s job to help educate the public about mosquito and vector control with the latter including ticks and such.

In doing so, she is spreading the word about the work and services of the district that delivers arguably the largest bang for the property tax dollar when it comes to public health and safety, not to mention annoyance reduction.

The annual average cost for residential property owners is $15.

Don’t fear the sharks & water,

fear water that yields mosquitos

The deadliest encounter humans can have with creatures in nature are not sharks, grizzly bears, rattlesnakes, or mountain lions.

It is mosquitos.

Worldwide, diseases transmitted by mosquito bites kill between 750,000 to a million people every year.

If you don’t think it can happen here, so far this year in San Joaquin County has had two confirmed cases of people getting sick from the West Nile Virus this year.

There were four deaths in California during 2025 attributed to the West Nile Virus including three in the San Joaquin Valley.

Malaria outbreaks — something that some attribute to only happening in jungle settings — was prevalent in California from the 1900s to 1950s.

It is what led to the formation of mosquito and vector districts up and down the state — including San Joaquin County in 1946.

It is the eradication and control district has done that has made local mosquitos a rare source for the roughly 2,000 malaria cases in the United States for Centers for Disease Controls reports annually. Those were mostly incidents of travelers contracting the disease in another country.

In 2023, there were a handful of cases originating with mosquito bites in Florida and one in Texas. Those were the first US originated cases since 2003.

San Joaquin County — with 55 percent of the 1,153 square miles of the Delta within its boundaries as well as an abundance of waterways and farming including rice fields — is fertile breeding grounds for mosquitos.

The district monitors the county. They will use microscopic aerial spraying plus from tanks mounted on trucks through infected neighborhoods. They also distribute passive preventative measures such as mosquito fish raised in 13 fish breeding ponds in Lodi.

That is addition to spraying at the source including in such places you might not consider such as standing water in gondola-style agricultural trailers.

There are times when crews are doing field work they come across spots they were unaware of where water had sat for long periods in open fields.

De la Vega said crews will share how their lower pants legs were almost completely covered with mosquitos.

If you don’t believe that mosquitos would be that bad sans the San Joaquin Mosquito & Vector Control District, talk to some people who were around in the county in the early 1950s.

Better yet, take a raft trip on a warm summer afternoon down the Stanislaus River between Stouffer Park in Ripon and Caswell State Park south of Manteca without long sleeve shirts and long pants and without benefit of Deet or other forms of mosquito repellent.

Don’t be surprised if at the end of the trip that your exposed skin is almost completely covered by welts from mosquito bites.

Be advised, however, doing so would expose you to mosquitos carrying the West Nile virus as the area around the river is a verified hot spot.

For more information, go to www.sjmosquito.com.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com