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West Nile Virus cases predicted to increase in NY due to climate change

DAVE MARQUES, HOST: It’s officially mosquito season in New York City, and you’re probably gonna notice it. In recent years record-breaking numbers of the insect have been plaguing the boroughs. More mosquitoes mean more diseases, like West Nile Virus.

REBEKAH ROBINSON, HOST: The city is trying to fight back to reduce the mosquito population. But as Clara Grunnet reports, climate change makes that a complicated task.

CLARA GRUNNET, BYLINE: One September afternoon 3 years ago, Doug Newton, couldn’t seem to get out of bed.

DOUG NEWTON: It was actually our wedding anniversary and we're supposed to go out to dinner and I couldn't get up and I was just really tired and not too cogent.

GRUNNET: Doug lives in a Brooklyn townhouse with his family. He doesn’t remember much from that day… His wife Kathy Newton says she thought he had the flu.

KATHY NEWTON: He couldn't even sit up and on the couch, he just sort of fell over. So he went back to bed and then he said, I don't think we're gonna go out for our anniversary, haha.

GRUNNET: That night Doug began to hallucinate, so they raced to the hospital.

KATHY: A doctor came in and said, we're taking him off the antibiotics. It's a virus. It's the West Nile virus.

GRUNNET: The effects of the virus kept him in the hospital for three months, and he says the illness still limits his mobility.

DOUG: I just cannot walk like a normal person. I'm very awkward. I'm out of balance. I can't raise this arm very far. And I got a tremor, shaky hands. I'm an artist and so that's no fun.

GRUNNET: The West Nile virus is a disease transferred from birds to mosquitos and then, as in Dougs case, sometimes to humans. Most people don’t get any symptoms at all. Others experience fevers, headaches, disorientation and extreme fatigue. And for some, particularly those over 50 or with weakened immune systems, the spinal cord or the brain can become infected–-and that can be fatal.

Doug was one of 10 New Yorkers who got West Nile Virus in 2019. Last year, that number was 21. Oliver Elison Timm is part of the Climate Change and Emerging Infectious Disease working group at Albany University. He says as temperatures in the New York area rise, mosquitos will thrive.

TIMM: So there is an optimum temperature range where we feel comfortable, but so is also activity in nature, right? Mosquitoes have an optimal temperature range where they thrive the best and reproduce the best.

GRUNNET: That’s why Timm expects to see a continued increase in West Nile cases in the Northeast. The City Health Department is tracking the rise in mosquitoes…they have an ongoing program of mosquito surveillance and control which includes removing standing water in the city, putting larvicide in street drains, and educating the public on prevention of mosquito-borne illness.

(Ambi of spraying truck)

Another key component of their plan is spraying the streets of New York with pesticides.

COHEN: they have a big arm that just starts spraying in all directions, just leaving the trail of spray? And it's harsh, you know, and you don't want to be caught in it.

(Ambi of spraying truck continues, then fades)

CLARA: Mitchel Cohen lives in Coney Island, he says the trucks drive by his house spraying clouds of pesticides. When the city first announced they would start spraying for mosquitos back in 1999, Cohen helped organize a group called the No Spray Coalition. He says the widespread use of insecticides can have unintended effects on urban ecosystems.

COHEN: What a stupid thing to do to think that the way of dealing with an ongoing disease day after day, year after year to just spray massive amounts of chemicals…. They don't even think about what happens to the birds or what happens to the frogs. What happens to the dragonflies that eat mosquitoes?

GRUNNET: I reached out to the City Department of Health, and they declined to comment on their use of pesticides. In their official mosquito control plan they acknowledge there may be negative impacts associated with spraying. But they emphasize that pesticides are used only when it is necessary and only when spraying can reduce the risk of disease.

Some researchers agree that blanketing neighborhoods with pesticides might be a necessary last resort, but only after trying more targeted methods of fighting insect-borne disease. Maria Diuk-Wasser is a professor at the Department of Ecology, Evolution and environmental biology at Columbia University. She says controlling these diseases requires a more nuanced understanding of the ways ecosystems are changing. As one example, she cites the effects of the recent boom in the deer population.

DIUK-WASSER: For example, deer overpopulation. They're very high densities of deer because there's no predators, and we're providing excellent resources for them. So they reproduce in, in big, big numbers. / And that is causing a lot of the tick borne diseases. That's an example.

GRUNNET: The CDC reports that nationwide mosquito and tick borne disease cases more than doubled between 2004-2018. Climate change researcher Oliver Elison Timm, says that overall insect-borne diseases will likely continue to increase in the near future, but the science remains uncertain.

TIMM: The lessons that we learned in the climate research community in general is that the more we are able now with our models to look at regional impacts, we can take into account more processes, more factors. And the story gets more complicated.

GRUNNET: In other words, warming causes ecosystems to change in complex and unpredictable ways.

TIMM: There are nonlinear effects. That makes our life more interesting, but also more complicated to predict or project what will happen with global warming.

GRUNNET: Maybe there will be more mosquitoes because of rising temperatures… But that increase could be canceled out by changing humidity levels. High temperatures could cause a drought…causing bird populations to decline. And thats fewer birds to pass West Nile on to mosquitoes and then on to humans.

TIMM: So that’s where these nonlinearities in the system can be very complex and what will win right? That's the question.

GRUNNET: And that uncertainty makes it hard to develop effective mosquito control plans for the future.

(Ambi of Birds in Doug’s garden)

GRUNNET: Back in his Brooklyn Garden, West Nile Survivor Doug Newton reflects on the predicted increase in West Nile Virus cases in New York, and his hopes for the future:

DOUG: I wish we weren't having climate change. I wish we could stop using fossil fuels. I feel very strongly about that. But with the situation as it is, all I can suggest is buying a can of ‘off’ and using it.

GRUNNET: The health department will continue spraying pesticides throughout the city, beginning by the end of this month.

Clara Grunnet, Columbia Radio News.

(Ambi fades out)

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