Aedes albopictus is an early riser. Of the fifty-one mosquito species in New York, albopictus—a close cousin of Aedes aegypti, the species responsible for spreading Zika—prefers to restrict its activity to power breakfasts, in the mornings, and to teatime, in the late afternoons. (The common house mosquito is active in the evenings.)
On a recent afternoon, Mario Merlino, the assistant commissioner for New York City’s Bureau of Veterinary and Pest Control Services, and Zahir Shah, the director of the city’s Medical Entomology Laboratory, jumped a small fence inside Bellevue South Park, in Kips Bay, and wandered into the shrubbery. Shah pointed to what appeared to be a black collapsible laundry hamper, hidden behind a bush. “There it is,” he said. “Our pride and joy.”
Aegypti is not prevalent in New York, but the health department isn’t taking any chances. The city recently pledged to spend twenty-one million dollars to combat Zika, and Shah’s lab has been beefing up its operations. It’s hiring more entomologists and lab assistants. It has also acquired new mosquito-hunting swag: the laundry-hamper thing was one of a hundred BG-Sentinels (two hundred dollars each), mosquito traps designed to target both albopictus and aegypti.
The new trap is cylindrical and shiny, with sides made of black fabric and a white plastic top. If you were a mosquito, you might find it good-looking—especially compared with regular mosquito traps, which resemble buckets. This is intentional. According to Shah, albopictus prefers “attractive visual cues.”
Regular traps release small amounts of carbon dioxide, to mimic humans breathing. The albopictus lure is more sophisticated: it releases a bouquet of substances commonly found on human skin, like ammonia and lactic acid, which are present in sweat and breath. The mosquitoes come to feast, and get sucked in. Shah unscrewed the trap’s bluish-white lure and took a whiff. It smelled like a hot subway car during rush hour. “Whoa,” he said. “It gets me every time.”
The medical-entomology lab is housed in an aging government building on First Avenue. It was set up in 2000, in response to the West Nile outbreak. Today, about twenty employees monitor the city’s mosquito populations. Five hundred and fifty New York City residents have tested positive for Zika, but so far no local mosquitoes have been discovered carrying the virus.
The lab’s staff have set traps at some hundred and twenty strategic locations around the city. Cemeteries, with their greenery, are mosquito hot spots, Shah said. Plus, there are the flower vases that people leave behind, which create ideal mosquito-breeding conditions. Lately, the trappers have been knocking on people’s doors in “hot” areas, asking to place albopictus traps in their back yards. So far, no one has refused. There are now a total of twenty traps on private properties.
The traps are set once a week and emptied after twenty-four hours. The trappers then place the mosquitoes in plastic tubes and put them on dry ice, which kills them. Each trap catches an average of seven mosquitoes per day. “We all get bitten all the time,” Merlino said. “But we obviously encourage everyone to carry bug spray. Nothing fancy—just the regular stuff from Duane Reade.”
Back at the lab, the samples were being catalogued and tested for both Zika and West Nile. Five on-site taxonomists identify around two thousand mosquitoes daily. They separate the genders: only female mosquitoes carry viruses, so the males can be tossed. “The males are easy to spot,” Shah said. They have “bushier” antennae. Peering into a microscope, he examined a fresh batch of albopictus. They didn’t look particularly hairy. “Ah—these must be females,” he said.
Two floors down, Jie Fu, a research scientist, oversees testing. First, she feeds a tube’s worth of mosquitoes into a machine that grinds them into a gelatinous glop. “It’s like when you make mashed potatoes,” she said. A machine called the BioRobot (imagine a convection oven) separates out the RNA and dollops it onto rectangular plates, which later go into a machine called an amplifier (imagine an office printer). Two hours afterward, the results appear on a small screen. “See?” Fu said, pointing to a bunch of squiggly lines. “No Zika.” She added, “Albopictus is slowing down. It doesn’t like the cold.”
As part of the larger effort to educate New Yorkers about Zika, the health department has been promoting a hot line that people can call to report incidents of standing water: puddles, brimming gutters, birdbaths. The police department was the first to benefit: before the hot line, people used to call 911 to complain about mosquitoes. “They’d say, ‘Quick! I have mosquitoes! Do something about it!’ ” Shah said. “Well, we’re doing something about it.” ♦