“As researchers learn more about the devastating health effects of Zika, county crews this past week continued an unprecedented effort to stop the virus from spreading locally.
“For the 10th time this year, San Diego County’s vector-control crews sprayed insecticide in a neighborhood known to have mosquitoes that can carry the virus. The latest spraying took place in the South County neighborhood of Nestor.
“As of Wednesday, 67 people in the county had tested positive for Zika this year after traveling abroad. But only 10 neighborhoods have been sprayed because in many cases, the targeted Aedes mosquitoes weren’t detected near the sickened residents’ homes.
“San Diego County hasn’t fielded any report of a locally acquired Zika case, while there have been 139 nationally this year.
“’It is encouraging,’ said Rebecca Lafreniere, deputy director of the county’s Environmental Health Department. ‘But we really emphasize our public-health message about preventing the breeding [of mosquitoes] in the first place.’
“She said the public can do its part by eliminating any pools of stagnant water — even small amounts.
“Other prevention tips include staying inside and bringing pets indoors, closing windows and doors, turning off fans that bring outdoor air inside and covering ornamental fishponds. The county also advises people to rinse fruits and vegetables from gardens before cooking or eating them, as well as wiping down or covering outdoor items such as toys and barbecue grills.
“San Diego County’s latest Zika-related spraying case arose amid what may be encouraging signs about the epidemic’s containment in the U.S. and internationally.
“A study released by the agency last week urged further caution for new mothers; it cited research showing that severe birth defects caused by Zika may not be apparent at birth but develop months afterward. The CDC now recommends long-term monitoring of babies born to Zika-infected women.
“Aedes mosquitoes didn’t gain public awareness in the U.S. until recent years, but they’ve long been a scourge in several other parts of the world. They can transmit not only Zika, but also yellow fever, dengue fever and chikungunya.
“In San Diego County, Lafreniere said the Aedes aegypti, also known as the yellow fever mosquito, and the Aedes albopictus, or the Asian tiger mosquito, were first reported in 2014 and 2015, respectively. Their appearance was a game-changer for the region’s vector control officials, who deal with most mosquito species by trying to kill larvae or reduce breeding areas.
“In the past, San Diegans who contracted mosquito-borne diseases while abroad weren’t a public-health threat once they returned home because those non-Zika viruses essentially had no way to spread here. Aedes mosquitoes are considered more invasive, and they’re adept at surviving and expanding their populations in urban areas.
“Vector-control crews must go after the adults, specifically the females that bite people and spread the Zika virus, Lafreniere said.
“She also said the county was prepared for responding to Zika because it has a plan for dealing with emerging vector-borne diseases. Likewise, the county has a reserve budget for an emergency public-health threat and follows an existing integrated pest-management approach that addresses public information and education, mosquito surveillance, biological control, physical control and microbial and chemical control.
“Fighting Aedes mosquitoes hasn’t been without its challenges, though. Lafreniere didn’t cite a dollar amount last week, but said the anti-Zika work has created a ripple effect on her department.
“’Because we’ve had these 10 (spraying) responses, it has shifted some of our operational needs,’ she said. For example, she said the county’s standard response time of one day for a vector-control issue has sometimes been stretched to two days because of the anti-Zika efforts.
“Besides working to combat the new invasive mosquitoes, the county is dealing with a longer mosquito season, which traditionally was during the warmer months of April through October.
“’What we’ve been experiencing in the last few years is very mild winters,’ Lafreniere said. “We’ve been seeing more mosquitoes in the winter, which is unusual."
Source: The San Diego Union-Tribune