On March 10, Rep. Sheila Jackson Lee held a news conference at the Good Neighbor Healthcare Center in the part of Houston she represents. The mayor and a bevy of other state and local officials stood behind her.

“What we’re doing here today is having an intense briefing on the Zika virus with health professionals, working with the mayor and the city of Houston, the state and the country, to formulate the kind of partnership that can respond immediately,” said Jackson Lee, a Democrat.

Then she stepped aside, as the mayor, the assembled health officials and civic minded clergy all delivered a version of the same message: The Zika virus is coming to Houston, and we’d better get ready.

To get a better idea why Houston is at particular risk, I met up with Peter Hotez. He’s dean for the National School of Tropical Medicine at the Baylor College of Medicine.

Hotez says there are three elements that put Houston at risk for a Zika outbreak. The first is the steady influx of people from other countries.

“Houston is a gateway city,” says Hotez. “We’re on the coast; we’re not far from the Panama Canal. We’re an immigrant hub.”

There’s also a major international airport. “Every day there are hundreds and thousands of people coming from all over the world to Houston,” he says. At least some of those people are likely carrying Zika, according to Hotez, whether they know it or not.

The second element is mosquitoes. In the summer, Houston is awash in Aedes aegypti. That’s the mosquito that can transmit Zika.

The third element is economic. “I think one of the missing narratives that we’ve not heard about Zika is that this is a disease of poverty,” says Hotez.

To show me what he means, we drive to a neighborhood called the Fifth Ward, just a few miles from the gleaming skyscrapers of downtown Houston. The area near the corner of Worms and New Orleans Streets is dotted with small, dilapidated wooden homes. There are few, if any, grocery stores or restaurants nearby.

Hotez says there are often piles of trash here, trash where water can pool and provide breeding grounds for Aedes aegypti.

Hotez points to a pile of tires. “What happens, the water pools inside the tire well,” he says. “But the other thing that happens is that as the water sits for a time, some of the leaves get into that, and it kind of creates an organic soup that the mosquito larvae absolutely love. So as we move into the spring and summer months, these will be teeming with thousands of Aedes aegypti mosquitoes.”

If these mosquito should happen to bite someone infected with Zika, and then bite someone else nearby, that second person will become infected. This is how the virus can spread through a neighborhood.

Now if you’re in a home with window screens and air conditioning, that’s one thing. But there aren’t many homes like that around here.

“We’re only a few feet from a house which has no window screens,” says Hotez, “So it’s the proximity of a house with no window screens, next to the discarded tires, next to the standing water that creates the perfect mix” for spreading the virus.

Hotez says the point is American cities like Houston have quite a high concentration of poverty. He says it’s the poor who are the most exposed to mosquitoes, and therefore most vulnerable to mosquito-borne diseases.

City, county and state officials say they’ll do all they can to pick up trash where mosquitoes can breed. They say federal health officials are keeping watch at Houston’s international airport to make sure travelers who do show up with Zika are identified and treated.

But they’ll need residents’ help, both in clearing trash and seeking medical attention if they think they’ve been exposed to the virus.

Hotez says these efforts may not stop Zika from hitting Houston, but he hopes they will at least minimize its impact.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.

Transcript :

ROBERT SIEGEL, HOST:

The Gulf Coast is preparing for the arrival of Zika. That’s the virus that’s been linked tentatively to birth defects in other countries. In Houston, experts say, it’s a matter of when the disease will arrive, not if. NPR science correspondent Joe Palca visited the city to learn more.

(SOUNDBITE OF ARCHIVED RECORDING)

SHEILA JACKSON LEE: Good morning. Thank you so very much for being…

JOE PALCA, BYLINE: On March 10, Congresswoman Sheila Jackson Lee held a news conference at the Good Neighbor Healthcare Center on Heights Boulevard in Houston. The mayor and a bevy of other civic leaders stood next to the Congresswoman.

(SOUNDBITE OF ARCHIVED RECORDING)

LEE: What we’re doing here today is having an intense briefing on the Zika virus with health professionals working with the city of Houston, the state and the county to formulate the kind of partnership that can respond immediately.

PALCA: One by one, the members of the partnership came to the microphone – Mayor Sylvester Turner…

(SOUNDBITE OF ARCHIVED RECORDING)

SYLVESTER TURNER: The city is taking the Zika virus very seariously.

PALCA: …County health official Umair Shah…

(SOUNDBITE OF ARCHIVED RECORDING)

UMAIR SHAH: The county is very much engaged in this.

PALCA: …Bishop James Dixon.

(SOUNDBITE OF ARCHIVED RECORDING)

JAMES DIXON: We stand ready to walk the streets, knock on doors, whatever’s necessary…

PALCA: Why are all these officials so sure that the Zika virus will show up in Houston, and why will knocking on doors help? Well, to get a better idea, I met with Peter Hotez. He’s dean for the National School of Tropical Medicine at the Baylor College of Medicine. Hotez says there are three elements that put Houston at risk for a Zika outbreak. The first is the steady influx of people from other countries.

PETER HOTEZ: Houston is a gateway city, right? We’re on the Gulf Coast. We’re an immigrant hub.

PALCA: And there’s a major international airport.

HOTEZ: Every day, there are hundreds and thousands of people coming from all over the world to Houston.

PALCA: And Hotez says at least some of those people are likely carrying Zika whether they know it or not. The second element is mosquitoes. In the summer, Houston is awash in Aedes aegypti. That’s the mosquito that can transmit Zika. And the third element – Hotez said a short car trip from the health center would reveal that.

HOTEZ: Joe, I thought I’d take you to some of the poor neighborhoods of Houston. Today, we’re going to head over to the Fifth Ward.

PALCA: We get in the car and head away from the gleaming skyscrapers of downtown.

COMPUTER-GENERATED VOICE: Continue onto Waco Street.

HOTEZ: I think one of the missing narratives that we’ve not heard about Zika is that this is a disease of poverty.

PALCA: Poverty – the third element that Hotez says puts Houston at high risk. We’re only a couple of miles or so from downtown, but the landscape here is completely different. There are small, dilapidated wooden homes, and there’s also plenty of open green space and a rooster.

But here’s the problem. Poor neighborhoods are often places people come to dump their trash, trash where mosquitoes can breed. Hotez points to a pile of tires.

There’s probably about two dozen tires just sitting on the side of the road.

HOTEZ: If we walk over and look at these tires, first of all, you’ll see they have water in them. But the other thing that happens is as the water sits, some of the leaves get into that. So there’s – it kind of creates an organic soup that the mosquito larvae absolutely love. So as we move into the spring and summer months, these will be teeming with thousands of Aedes aegypti mosquitoes.

PALCA: Which, if they bite someone carrying Zika, they can transmit the virus to someone else nearby. Now, if you’re in a home with window screens and air conditioning, that’s one thing, but standing by these tires…

HOTEZ: We’re only a few feet from several houses that have no window screens. So it’s the proximity of the house with no window screens next to the discarded tires next to the standing water. That’s – creates the perfect mix.

PALCA: For the spread of the Zika virus. Hotez says the point is American cities like Houston have quite a high concentration of poverty. And it’s the poor that are the most exposed to mosquitoes and therefore are the most vulnerable to mosquito-borne diseases.

City, county and state officials will do all they can to pick up trash where mosquitoes can breed and make sure travelers who do show up with Zika are identified and treated.

But they’ll need residents to do their part – remove trash, dump out standing water and flowerpots or wading pools and go to the doctor if they think they’ve been exposed to the virus. Hotez says these efforts may not stop Zika from hitting Houston, but he hopes they’ll at least minimize its impact. Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.