Climate Change Will Prolong U.S. Mosquito Season, Lead to Spread of Zika Virus
Report from Climate Central shows warmer weather adds 30 extra days of mosquito-breeding time to areas across America
KIM BROWN: Welcome to the Real News Network. I’m Kim Brown.
On Monday, the Texas Department of State Health said a resident of El Paso County was diagnosed with the Zika virus after traveling out of state. But this person wasn’t visiting the Caribbean or Central America, they had been to Miami, Florida where there had been 15 confirmed cases of the Zika virus transmitted locally in the Miami neighborhood of Wynwood. Zika is here, it’s probably here to stay and definitely here to spread. But Latin America is the one bearing the brunt of this disease. Especially in Brazil, home of the summer Olympic Games in Rio where there have been 4,000 cases of microcephaly, a debilitating birth defect caused by Zika transmission to pregnant women. Now some scientists argue that climate change could be a solid reason why we’re seeing such a swift spread of Zika carrying mosquitoes. One such scientist joins us today.
Alyson Kenward is the vice president of creative production at Climate Central which is an independent organization of scientists and journalist reporting on issues of climate change. She joins us today from Boston. Alyson, good day.
ALYSON KENWARD: Hi.
BROWN: Alyson, your organization released a report about how mosquito season is growing longer. Especially in cities in the south and along the East Coast, thus increasing the likelihood of the Zika virus spreading. What does your research show?
KENWARD: Yea so we looked at what are the climate conditions that are amenable for mosquitoes that have the ability to carry and transmit the Zika virus and how are regions across the eastern US and really nationwide, having more of those days since the 1980s. So what we found is that there has been an increase in most of the country of the number of days on average each year where the climate is really amenable to having these mosquitoes live and thrive. In some places, many more days, 20, 30, 40 more days every year where these mosquitoes could be living.
BROWN: Alyson, so is winter not having the same effect on killing mosquitoes as it used to?
KENWARD: Well we didn’t look exactly at the season where those climate conditions are not in play and what that means for those mosquitoes’ kind of coming back in the spring. What we do know though is that there’s many more days each year where mosquitoes could be thriving. So if the mosquitoes are present they’re likely to remain a lot longer and could be a threat.
BROWN: So what are some of the climate conditions that you’re see in in Central and South America that has been able to foster this Zika outbreak as it were?
KENWARD: Right so let’s take a step back and talk about the mosquitoes themselves. You know there are a couple types of mosquitoes that are known to be able to transmit the Zika virus. There’s a major one that’s really a tropic mosquito and the second one that is lesser associated with the transmission but it is able to transfer the disease and it has a much broader range and it continues. It can thrive up the eastern seaboard up to New England say. So we’re really looking at the risk of that mosquito, that’s the one that we were focusing on in our analysis because it’s much more applicable for the United States.
But mosquitoes need warm humid conditions. We all know that. You’ve got rain you’ve got standing water, you can mosquitoes being born under those conditions and then you know we know that mosquitoes come out in the summer and you ‘ve got warm conditions but not really hot and they need humidity. So we’re really examining the spread of these warm and humid conditions over time in the US.
BROWN: So Alyson, break this down to us like we’re in 9th grade biology. What’s different about what we’re seeing with these Zika carrying mosquitoes as opposed to other mosquito borne illnesses like H1N1 or dengue or even malaria. What are we seeing different about the Zika?
KENWARD: Actually we’re seeing things that are very similar with these other diseases. In fact, the mosquitoes that can transmit Zika are also mosquitoes that can transmit some of these other diseases that you’re talking about. And so really when we’re talking about the risk for Zika we’re talking about the risk for several of these diseases. Zika’s really what’s on people’s minds right now and as we mentioned off the top, now it’s present in the United States so transmission in the United States by mosquito has really become something we need to look at.
But in terms of what’s the spread of Zika from South and Central America into the United States. Really you mentioned it, how this disease has come to the US is via travelers bringing Zika back home and now it’s being spread because of mosquito transmission.
BROWN: So are you saying that there could even be the possibility that mosquitoes who can transmit worst diseases like dengue and malaria, that could possibly be in our future? Not in the immediate future but it could be on the table?
KENWARD: Yea it’s really hard to say what the pattern of transmission of these diseases could be. But we do know what you need for transmission is the mosquito itself and what our analysis was showing was that the conditions for which the conditions can live especially for longer seasons is increasing in time and also time and also growing across the country. So much more of the country is seeing a longer season that mosquitoes could be living.
BROWN: Alyson, there was chilling piece in the guardian on Wednesday that outline how costly and complicated it is to test people for the Zika virus. Because of that, the article speculated that Zika could be more widespread in the US but we really don’t know because the testing simply isn’t being done. Is that something that you would agree with? Or have you seen that in your research?
KENWARD: I haven’t looked specifically at that. I think really people have their eye on Zika at the moment because we knew that the outbreak was happening in South America, Central America and that there are travelers from the United States, constantly coming and going from there. And we’ve known that Zika is present in the United States coming back with travelers. And now we have confirmation that there is transmission from someone in the United States to someone in the United States.
So it’s no longer that all the Zika cases in the US are just from travelers. So I do think people are really on the lookout for the incidents of Zika. So per usual, the United States Congress is [stamlied] on addressing public health. Not only are they on a 7 weeklong vacation, they left town without passing any bills related to funding the fight against Zika.
Now local health agencies in potentially affected areas are urging residents to be vigilant about addressing standing water on their property, etc. and there’s been a lot of spraying going on. I know they spray in my neighborhood for mosquitoes. Now Allyson, are these quality methods for attacking the mosquitoes or is this sort of the bare minimum that could be done right now to address this?
KENWARD: Well I think people need to take their own initiative to do what they can to prevent mosquito bites. So using the appropriate repellents, staying out of the way when there has been standing water and there is a greater likelihood of being mosquitoes present. What’s really important is also to consider the increasing risks.
So again we have transmission within the United States now happening and really I think it’s important not just to focus what’s happening this year but what the risk is going forward. We’re seeing more days now where we can have these types of mosquitoes and that’s because temperatures are warming and areas are becoming more humid. So we need to not focus just on what’s happening this year and people that had brought it from abroad but really think about the risk for Zika and other mosquito borne disease going forward as we see greater warming.
BROWN: So the World Health Organization believes that they may actually be dealing with as many as 4 million cases of Zika infection by year’s end. In some areas they’ve seen a 20 fold increase of the amount of Zika transmission from year over year, from last year to this year. Do you have any predictions about what the US can expect for possibly summer of 2017?
KENWARD: No I think that’s really going to depend on what the winter holds. What the climate conditions are through the winter. How many people are continuing to travel to regions still primarily Zika’s coming into the country through travelers and we’re now seeing the added threat of transmission within the country.
So I think depending on what the climate is like through the winter and what the climate conditions are into next year, that’s what’s going to dictate the spread of Zika in the next year or so. But again what our analysis has looked at is not just the risk of a single year to a single year but what’s the long term trend and since the 1980s we’re seeing warmer and more humid conditions and we’re projected to see that going forward.
BROWN: Alyson Kenward. She is a senior scientist and a VP of creative production at Climate Central in Boston. We appreciate your time today Alyson.
KENWARD: Yea thanks for having me.
BROWN: And thank you for watching the Real News Network.
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