Zika Scare Won’t Alter Vector Plan

Homeowners told to drain standing water
It is incumbent on property owners to be proactive, particularly to prevent and eliminate standing water. Matthew Charron

The Zika virus, spread primarily through the bite of an infected mosquito, was declared a public health emergency of international concern by the World Health Organization last month, nine months after the Pan American Health Organization issued an alert regarding the first confirmed infection in Brazil. Though symptoms of Zika in an infected person are usually mild, the virus can be spread from a pregnant woman to her fetus and has been linked to microcephaly, a serious birth defect of the brain. The federal Centers for Disease Control and Prevention has recommended that pregnant women should not travel to areas with Zika.

The virus can also be spread from mother to child if she is infected around the time she gives birth. An infected man can spread Zika to his sex partners, and it can also be spread through blood transfusions.

To date, no vector-borne Zika infections have been acquired in the United States, according to the C.D.C., but 273 travel-associated cases had been reported as of March 23. The virus, according to the C.D.C., is likely to continue spreading to new areas.

While Zika has fostered public concern, its appearance is unlikely to significantly alter the vector-control efforts of the Suffolk County Department of Public Works, which have been aimed at mosquito species that carry the West Nile and Eastern equine encephalitis viruses. Beginning in early May, the county conducts aerial application of the larvicide methoprene over marshlands to control those insects, while one of the likely vectors for Zika, Aedes albopictus, or the Asian tiger mosquito, “tends to live around the household,” said Dominick Ninivaggi, the vector control division’s superintendent.

The Asian tiger mosquito, he said on Tuesday, “breeds in containers in nature, like tree holes, and things like a little bucket, a birdbath, those little habitats. It’s not the mosquito you find in a swamp or marsh.” The suburban areas typical of western Suffolk County are more likely to see the Asian tiger mosquito than the South Fork, Mr. Ninivaggi said. Aedes aegypti, known as the yellow fever mosquito, is another species that is believed to carry Zika.

The county sprays marshlands with methoprene, but to control Zika-carrying mosquitoes, “it would be a matter of delivering it to the sites,” Mr. Ninivaggi said. “There has been some work done using fogging-type methods and others to reach backyards, but this is probably pretty unlikely for us.”

Instead, he said, it is incumbent on property owners to be proactive, particularly to prevent and eliminate standing water. “We can’t go into everybody’s backyard and treat it, turn over the birdbath. A lot of this will be education and outreach, having people take precautions, using repellants.” Control of the Asian tiger mosquito is difficult, he said, “and very annoying, because it can bite in the daytime and be very aggressive.”

On March 17, Gov. Andrew M. Cuomo announced an action plan to combat transmission of Zika in the state. This includes distribution of larvicide tablets to residents in potentially affected areas.

That the Asian tiger and yellow fever mosquitoes’ habitat differs from that of West Nile-carrying mosquitoes is little comfort to activists and officials opposed to the county’s use of methoprene, which they say is harmful to nontarget species including lobsters and crabs.

Kevin McAllister of Defend H2O has long been a vocal critic of the county’s aerial application of methoprene and the adulticide resmethrin. In January, he and Tyler Armstrong of the East Hampton Town Trustees asked State Senator Kenneth P. LaValle to co-sponsor Assemblyman Fred W. Thiele Jr.’s bill that would ban use of methoprene in any fish habitat in any municipality adjoining Long Island Sound and the Atlantic Ocean, along with their connecting bodies of water, bays, harbors, shallows, and marshes. Days later, Mr. LaValle introduced a Senate counterpart to Mr. Thiele’s bill.

“It’s unfortunate,” Mr. McAllister said. “When I heard about Zika, and then when it got a foothold in the States, I thought, ‘Here we go again,’ after feeling there had been some progress to ratchet down methoprene. I can see elected officials getting gun-shy about trying to champion its removal when there is a potential threat of Zika. It’s taken years to get where we are, where there’s at least some opposition to it.”

The county’s vector control division, Mr. Ninivaggi said, will be on the lookout for Zika and prepare a contingency plan. “The most likely place we would see it would be in returning travelers,” he said, but “that doesn’t necessarily mean it’s going to go anywhere,” as a mosquito would have to bite an infected person and incubate the virus in order to spread it.

“The issue with the birth defects has certainly gotten people’s attention,” Mr. Ninivaggi said. “Prior to discovery that the virus causes that — we’re pretty sure of that at this point — it was looked at as a mild disease. There wasn’t a high level of concern until the situation in South America turned ugly.”