Metropolis well being officers have detected practically twice as many mosquito samples with West Nile virus up to now this yr in comparison with the identical time final yr, the well being division warned this week — although there haven’t been any stories of New Yorkers testing constructive for the mosquito-borne illness as but.
The well being division had recognized 612 West Nile-positive samples from 2,040 mosquito swimming pools examined citywide this yr by July 25 — an 88% improve from the 326 constructive swimming pools by the identical time in 2025, in response to figures the division launched Thursday.
The variety of constructive swimming pools rose to 850 on Friday, in response to the newest metropolis knowledge, with samples from Queens accounting for greater than 43% of all constructive detections and people from Staten Island accounting for an additional 33%. Officers didn’t instantly say how that quantity compares so far final yr.
The surge in West Nile virus amongst mosquitoes within the metropolis mirrors a broader improve throughout the nation, in response to the U.S. Facilities for Illness Management and Prevention. Nationally, greater than 140 individuals have examined constructive for the virus up to now this yr, with about half of them in Arizona.
“We have now had two warmth waves, in order that created an ideal situation for the virus to amplify and unfold,” Shamim Riaj, who helps lead a 14-person well being division division that screens disease-spreading mosquitoes and ticks, instructed The Metropolis Reporter.
Operations to handle the virus’ risk usually begin to intensify in April, Riaj added, as mosquito exercise crescendoes all through the summer time with the humid, subtropical local weather, peaking in August and September.
“When it rains, it creates situations for standing water in every single place, so it’s the proper place for mosquitoes to go and lay eggs and to in all probability begin to develop,” he defined. “Then let’s say the solar comes out after which there’s no rain for per week or two, it’s good breeding situations for mosquitoes.”
Listed below are 5 key issues to know in regards to the West Nile virus and the way town combats it.
What Is West Nile Virus?
The virus is primarily hosted by birds, however can unfold to individuals when mosquitoes contract it by biting an contaminated hen after which an individual.
The primary West Nile outbreak in the US befell in New York Metropolis in 1999, and the virus has been detected in metropolis mosquitoes yearly since. So far, it stays the one mosquito-borne illness recognized to contaminate people throughout the 5 boroughs, in response to the well being division.
Most individuals who contract the virus are asymptomatic, although roughly one in 5 individuals expertise a gentle sickness that may embody fever, headache, fatigue and nausea. In uncommon instances, the virus also can trigger extreme neurological sickness.
Adults 60 and older are on the best threat of extreme sickness from the virus, well being officers say.
Persons are usually thought-about “dead-end” hosts of the virus, as person-to-person transmission has been documented solely in uncommon instances on account of blood transfusion, organ donation or breastfeeding, in response to the CDC.
How Does the Metropolis Detect West Nile-Constructive Mosquitoes?
The well being division has performed routine surveillance of mosquitoes to mitigate West Nile virus because it was first detected within the metropolis in 1999. Employees arrange 53 traps throughout town twice per week to gather mosquito samples.
“Whenever you need to decide it up, oh my God, it will get throughout you,” stated Zurina Yusoff, a well being division vector ecologist. “Generally the web protects you, however I simply pray.”
These mosquitoes are killed on dried ice upon assortment, then despatched to a lab the place species are recognized below a microscope. Then, they’re examined for West Nile virus.
To observe viral exercise, the well being division focuses primarily on two of the 51 mosquitos species current in New York Metropolis: the golden-bodied Culex pipiens and the stripped “Asian tiger,” an aggressive species native to Southeast Asia.
“In comparison with once I got here right here in 1996, there are positively extra mosquitoes, extra mosquito bites,” stated Riaj, a local of Bangladesh. “Let’s discuss in regards to the Asian Tiger. I didn’t see any Asian Tigers again then working within the neighborhoods, within the parks. Now they’re in every single place.”
The place within the Metropolis Have West Nile-Constructive Mosquitoes Been Detected?
Contaminated mosquitoes have been present in each borough, however particularly Queens and Staten Island.
What Does the Well being Division Do To Fight the Virus?
The well being division addresses West Nile virus primarily in two methods:
- Making use of eco-friendly organic pesticides to nonresidential marshes, wetlands and pure mosquito-breeding habitats through helicopter to attenuate larvae earlier than they turn into biting adults.
- Conducting pesticide-spraying operations through vehicles in neighborhoods the place West Nile-positive mosquitoes have been recognized.
“One thing individuals don’t all the time perceive once they cease us on the road is that we don’t simply spray a neighborhood for nuisance mosquitoes,” stated John Zuzworsky, a well being division vector ecologist. “Our spray standards is 2 consecutive swimming pools of West Nile virus, with excessive numbers of biting mosquitoes. It’s not simply random.”
Since July, the well being division has performed 4 mosquito-control operations, together with aerial larviciding in 4 boroughs, in addition to truck-spraying in Queens and Staten Island, most lately on Wednesday.
“These operations usually scale back grownup mosquito populations by about 70% and reduce West Nile virus-positive mosquito swimming pools by greater than 85%,” the well being division stated in a press launch Thursday.
Truck-spraying operations can final greater than 9 hours, between 8:30 p.m. and 6 a.m. Pickup vehicles crawl from block to dam at as much as 12 mph, spewing plumes of pesticides as large because the truck from a diffuser on the tail. An escort car main the best way serves as a navigator for the spraying truck, blasting a message by a pair of audio system warning residents to go indoors, nonstop, on a loop — as much as 3,200 instances by the tip of the evening.
Spraying autos are additionally programmed to beep and alert exterminators once they strategy pure water areas so that they don’t contaminate water and hurt aquatic life, Yusoff stated.
Lastly, well being division inspectors reply to 311 complaints about standing water — breeding grounds for mosquitoes — and difficulty tickets for violations when obligatory.
What Precautions Ought to I Take?
Riaj beneficial householders scale back any standing water on their properties to keep away from creating breeding grounds for mosquitoes. Birdbaths and plant saucers are frequent sources of standing water, he stated.
The well being division has additionally suggested New Yorkers to empty standing water at the least as soon as per week from buckets, flowerpots, kids’s toys, traps and clogged gutters.
Mosquitoes that transmit West Nile virus are significantly energetic at daybreak and nightfall and after darkish — so you possibly can keep away from going open air at these instances throughout mosquito season in case you’re apprehensive about getting bitten.
“In case you’re popping out and planning to remain outdoors longer, attempt to put on full sleeve garments and pants, attempt to put on mosquito repellent,” Riaj stated. “That’s the perfect recommendation I may give you.”
