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'Rest assured,' Clackamas County, state officials ready for Zika mosquitoes


Dr. George Peck, director of the Clackamas County Vector Control District, said mosquitoes that can transmit the Zika virus haven’t made it into Oregon, so far — at least to anyone’s knowledge.

PHOTO COURTESY CCVCD - A Clackamas County Vector Control District employee collects a sample of larva in a local water source perfect for mosquito breeding. Last month, Oregon got its first laboratory-confirmed case of Zika in 2016. Oregon’s Public Health Division said there was no danger to the public after a woman contracted the virus in an affected country outside the United States. 

“What we want to be sure of is that we don’t have local transmission,” Peck said. “That type of mosquito would have to be flying around for that to happen, and to the best of our knowledge, the Zika-vectoring mosquitoes aren’t in Oregon.”

Oregon Health Authority confirmed Feb. 26 that the illness was spread from a man who had traveled in a Zika-affected country to his female sex partner, who had not traveled. Both people later tested positive for Zika.

“Though mosquito bites appear to be the most common way Zika is spread, there is increasing evidence for sexual transmission as well,” said Richard Leman, an OHA public health physician. “People who have been in Zika-affected areas in the previous two weeks and develop symptoms suggesting Zika should see their health care provider. CDC advises men with pregnant sex partners to use condoms or abstain from sex for the duration of the pregnancy.”

Because Zika is suspected of causing a birth defect called microcephaly, causing an unusually small head, federal officials have urged pregnant women to postpone traveling to areas where transmission of the Zika virus has been detected. In most people, the virus leaves the bloodstream after a week, and only one in four infected people shows symptoms.

The Brazil Ministry of Health has reported an increased number of people who have been infected with Zika virus who also have Guillain-Barré syndrome, a rare auto-immune disorder of the nervous system in which a patient’s own white-blood cells cause paralysis. Before 2015, Zika outbreaks were localized to areas of Africa, Southeast Asia and the Pacific Islands.

PHOTO COURTESY CCVCD - Clackamas County Vector Control sprays larvacide at a known mosquito source in Clackamas County. On Feb. 1, the World Health Organization declared a public health emergency, and on Feb. 8, President Obama requested $1.8 billion in emergency funds for several federal agencies to accelerate research into a vaccine and educate populations at risk for disease.

Zika is spread by two species of mosquito common in Central and South America. Aedes aegypti, also called the yellow fever mosquito, is the primary Zika vector and invaded California three years ago. It since has been increasing its range within the state.

Peck says that Oregon vector control authorities will be watching for invading Aedes mosquitoes, especially since they may expand their range northward from California. This range expansion could easily be aided by unwitting humans who somehow trap a mosquito in their car on their way across state lines.

“We’re preparing our district for Aedes mosquito surveillance this summer,” Peck said. “We all know our climate is warming, and warmth is what these Aedes mosquitoes love. A warmer, wetter climate allowed them to invade California.”

Peck said Clackamas County Vector Control is preparing in coordination with other local jurisdictions in the surveillance and control of Zika virus vectors.

“We have a highly trained staff, an integrated pest management plan, and a fine public outreach and education plan, and thus we have all the tools that we need to control mosquitos,” Peck said. “We rarely spray for adult mosquitoes; we more often use environmentally friendly larvacides in wetland areas and distribute mosquito-eating fish to the public. During the winter months, we maintain vehicles and facilities, host educational opportunities and prepare to hire seasonal employees to go out into the field with trucks looking for mosquitoes spring through fall.”

Peck is a seasoned vector biologist who has published more than 10 publications on the subject of vector biology and medical entomology. His career includes working at Walter Reed Army Institute of Research, Washington State University, NW Mosquito and Vector Control District, and the University of California.

“We’re experts, and the people of Clackamas County can rest assured that we will do our part to keep the mosquitoes at bay,” Peck said.

To do your part, call the Clackamas County Vector Control District for a free inspection of suspected mosquitos on your property. For more information, visit fightthebites.com or call 503-655-8394.