Aedis aegypti, found in Ashland for the first time, is capable of spreading Zika and dengue; officials widen search and urge residents to eliminate standing water

By Damian Mann for Ashland.news

A disease-spreading, invasive mosquito with a penchant for human blood has been discovered in neighborhoods of south Ashland.

Known as aedes aegypti (pronounced like “80s egypti”), it was previously discovered in Talent last year, and was found this week in the Clay Street Park neighborhood, setting in motion a response from Jackson County Vector Control District, which has set up traps and placed door hangers in the area of Clay and Glendale streets, south of Main Street and north of Siskiyou Boulevard.

A total of 25 aegypti have been found after three days of setting out traps.

On Tuesday, six aegypti were found, and a wider search on Wednesday trapped 16, followed by three trapped on Thursday.
The mosquito, which has evolved to target humans specifically, has spread dengue, chikungunya, yellow fever, and Zika diseases in other parts of the world, but so far aegypti found locally have shown no trace of these diseases.

Aegypti have proliferated in other parts of the country, including in California.

The mosquitoes have also been referred to as Egyptian mosquitoes, dengue mosquitoes or yellow fever mosquitoes.

“They are really responsible for a lot of the disease around the world,” said Andrew Partin, Jackson County vector ecologist.

Active during the day, aegypti target humans as their favorite meal and can quickly spread disease.  “They tend to bite multiple people during a blood meal,” Partin said.

Partin and Joe Baures, mosquito surveillance technician, collected eight mosquito traps Thursday morning around Clay Street Park, taking them back to the lab for analysis.

Some residents have told vector control that they have already recognized the aegypti with their distinctive black and white coloring and graceful lyre shape.

“It’s a very beautiful mosquito,” Partin said.

His colleague, Baures, was setting a trap this week and found one sitting on a leaf and snapped a photo of it. So far, the duo haven’t seen high numbers of aegypti compared to last year in Talent, though none have been found in Talent this summer.

Both Partin and Baures said last summer’s public awareness campaign to stamp out aegypti in Talent has paid off, and they’re hoping for the same response in Ashland.

“We’ve seen a huge cultural shift in Talent,” Partin said.

Talent was the first area in Oregon where aegypti were discovered.

Because they prefer human blood, the aegypti are most active during the day and are aggressive biters, feeding on ankles, wrists and elbows.

They can lay larvae in 1/4-inch of standing water.  Marsha MacCormack, who lives near Clay Street, let Partin and Baures set up traps in her shady backyard with a creek flowing through the middle.

MacCormack said she makes sure she has no standing water in her yard to discourage all mosquitoes from breeding.

“They’re miserable little critters,” she said.

The door hangars help alert residents to the dangers of the mosquitoes and to take action to prevent standing water.

Residents are encouraged to alert vector control if they find aegypti by calling 541-826-2199 or going to jcvcd.gov/mosquito/aedes-aegypti/.

“Once people are aware we have the mosquitoes, then we get the calls,” Partin said.

Baures is particularly adept at setting up the specialized traps, called BG Trap Sentinel from Biogents, that lure aegypti inside netting.

“We call him “Joe the BG pro,” Partin said.

Baures said, “This is what I do all day.”

He said he knocks on doors and asks permission to set up the traps, also asking if he can go into their backyards to take them out or check on them.

Baures estimates that less than 5% of people say “no.”

“People in general care about public health,” he said.

The BG traps have a bucket-shaped canister with a fan that sucks the mosquitoes inside, entangling them in netting. The netting is pulled out and placed into a plastic bag, where it is frozen back at the lab so it can be inspected. Carbon dioxide is pumped into the canister and a small scent device adds extra enticement for the aegypti.

“It’s supposed to mimic how an organism, in this case a human, helps attract the mosquitoes,” Baures said.  The mosquitoes prefer older, established neighborhoods with shade trees and more vegetated backyards.

Aegypti were found in California for the first time in 2013, and by 2020, they were discovered in Redding.

“Since 2022, the aegypti have exploded in Redding,” Partin said.

The effort to control the spread of aegypti extends beyond Jackson County.

Partin said he works with the Connecticut Agricultural Experiment Station, and U.C. Davis sponsors summer internship programs, which helped to train Baures.

Emilio DeBess, state public health veterinarian in the Oregon Health Authority’s Public Health Division, said aegypti’s discovery in Oregon is a concern because the species has been more common in much warmer climates of the United States, Southeast Asia, Africa and the Pacific Islands.

“These mosquitoes have been known carry and transmit diseases that are more typical to warmer climates, such as Zika virus, chikungunya, dengue and yellow fever,” DeBess said.

However, DeBess emphasized that the risk of these infections to local residents is low.

“Acquiring these diseases depends on the presence or arrival of someone who is currently infected with one of the diseases after infection outside the United States,” DeBess said in a news release. “As was the case when Ae. aegypti mosquitoes were first found in Oregon in 2024, there have been no reports of anyone having acquired viruses associated with Ae. aegypti from within the state.”

Staying safe

Residents can take these steps to help prevent the spread of aegypti:
    • Dumping or draining any standing water around the home.
    • Removing containers or objects that can hold water from your yard, such as water saucers from under plants, old tires, tarps, buckets, containers, toys, and other equipment.
    • Repairing leaky outdoor faucets.
    • Keeping rain gutters cleared.
    • Covering, screening, or removing rain barrels, trashcans, bins, buckets, or tubs.
    • Wearing mosquito repellent outside. Repellents containing DEET, picaridin, IR3535, some lemon eucalyptus, and para-menthane-diol products are most effective at preventing mosquito bites.
    • Sleeping under a mosquito net when outside or in a room without screens.

Reach freelance writer Damian Mann at [email protected].

Related story: Oregon officials find mosquito that can transmit deadly viruses in Southern Oregon (Aug. 31, 2024)