They transmit viruses by biting infected humans, their favorite food, but local risk is low, officials say
By Lynne Terry, Oregon Capital Chronicle
For the first time, Oregon health officials have found a type of mosquito in the state that can transmit deadly viruses.
The Oregon Health Authority announced Thursday that it had found Aedes aegypti mosquitoes in Jackson County as part of its regular mosquito surveillance.
“Aedes aegypti mosquitoes are a concern in the United States because they can carry and transmit various diseases that can have serious health consequences such as Zika virus, chikungunya, dengue and yellow fever,” said Emilio DeBess, Oregon Health Authority’s public health veterinarian. The latter two viruses are potentially deadly.
The first mosquito was found July 23 in Talent, according to Jackson County officials. Since then, officials have found 77 specimens in 18 traps in northwest Talent. The initial discoveries were made weeks apart. Jonathan Modie, a spokesman for the Oregon Health Authority, said the state waited until now to alert the public because officials needed time to “conduct further surveillance and for local, county and state agencies to coordinate a response to ensure residents had accurate information once the public announcement was made.”
For more information:
Visit the Centers for Disease Control and Prevention website: cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html.
Jackson County’s vector control page: jcvcd.org/mosquito/aedes-aegypti.
Insect control officials set traps statewide on a regular basis to monitor mosquito activity and test for Western equine encephalitis and West Nile virus. The latter, which is also carried by other mosquitoes, typically affects horses and birds as well as humans. According to the Centers for Disease Control and Prevention, nearly 290 people in the U.S. this year have been infected with West Nile virus, including Anthony Fauci, the former director of the National Institute of Allergy and Infectious Diseases and a COVID expert, who was hospitalized. About 50 mosquitoes in Oregon have tested positive for the West Nile virus this year, health officials said.
The health authority said in its release that Jackson County health officials are working to control the insects and prevent the spread of disease, including eliminating standing water where they breed. Jackson County officials will go door-to-door in areas where they’ve been found to tell residents about the mosquitoes and inform them on how to eliminate the threat, Modie said.
As adults, Aedes aegypti mosquitoes are only about one-quarter of an inch long and have a speckled black-and-white pattern on their legs and other parts of the body. Scientists suspect they first appeared in Africa. They can’t fly far – only about 500 feet – but they’ve been transported by trade and shipping to tropical and subtropical regions around the world and have emerged in other temperate climates. They’ve also been found across the U.S., including along the Gulf coast, in Indiana, Kentucky and Arizona. They first turned up in southern California in 2013 and have also been found in the San Francisco Bay area, Washington D.C. and New York. They’ve yet to appear in Washington state.
Aedes aegypti mosquitoes prefer warm and wet weather and often live near homes or nearby woods. They target humans, their favorite food, and bite during the day, particularly ankles, wrists and elbows.
Health officials said the risk of contracting a virus like Zika, chikungunya, dengue and yellow fever from them is low because they have to bite an infected person first.
“The risk of these infections to local residents is low and depends on the presence or arrival of someone who is currently infected with one of these diseases after infection outside the U.S.,” DeBess said.
The health authority has not received any reports of deadly diseases passed to Oregonians by these mosquitoes, DeBess said.
They only need a quarter of an inch of water to complete their life cycle and can thrive in plant saucers, tires, kiddie pools, pet water bowls, containers and buckets and other water.
“Many prevention methods that work for other types of mosquitoes apply to Aedes aegypti,” said Geoff Taylor, manager of Jackson County vector control.
To prevent their spread, officials say people should:
- Dump or drain standing water around the home.
- Remove 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.
- Repair leaky outdoor faucets.
- Keep drain gutters cleared.
- Cover, screen or remove rain barrels, trash cans, bins, buckets or tubs.
- Wear mosquito repellent outside. Repellents containing DEET, picaridin, IR3535, some lemon eucalyptus, and para-menthane-diol products are most effective at preventing mosquito bites.
- Sleep under a mosquito net outside or in a room without screens.
DeBess said the health authority’s tracking and monitoring system will help reduce the risk posed by these mosquitoes.
Lynne Terry has more than 30 years of journalism experience, including a recent stint as editor of The Lund Report, a highly regarded health news site. She reported on health and food safety in her 18 years at The Oregonian, was a senior producer at Oregon Public Broadcasting and Paris correspondent for National Public Radio for nine years.
