The National Institutes of Health’s Anthony Fauci warned that Texas and Louisiana could be next for Zika.

In the weeks since mosquitoes carrying the virus hit U.S. borders, they have already spread from a small suburban community in South Florida to Miami’s most popular tourist spot, South Beach. The development prompted a travel advisory from the Centers for Disease Control and Prevention on Friday urging pregnant women to avoid the area.

Fauci, director of the Institute of Allergy and Infectious Diseases, speaking Sunday on ABC’s “This Week,” said the situation is likely to get worse soon.

“I would not be surprised if we see cases in Texas and Louisiana, particularly now where you have the situation with flooding in Louisiana,” he said. “There are going to be a lot of problems getting rid of standing water.”

Over the past year, infections from the virus have reached epidemic proportions in parts of the world. The World Health Organization has said that Zika may be responsible for thousands of babies being born with a severe birth defect known as microcephaly and for some adults coming down with neurological conditions. More than 50 countries have been impacted, with Brazil being the epicenter of the outbreak.

The United States had been mostly spared until now, but officials had said that the arrival of Zika in the country was inevitable because of the way the mosquitoes travel northward during the summer months. The officials have been making preparations on numerous fronts.

This month, federal researchers announced that they had begun their first clinical trial of a vaccine in humans. It will involve at least 80 healthy volunteers. But even in the best-case scenario, it could be a long time before an effective vaccine is available to the public. According to the most optimistic timeline, larger-scale trials could begin in early 2017 with the vaccine. After that, the researchers would have to go through the Food and Drug Administration approval process and then manufacture and distribute the vaccine.

There had been concern that athletes and tourists returning to their home countries after the Summer Olympics in Rio de Janeiro could accelerate the spread of the virus. According to a risk analysis by U.S. health officials, that risk is low other than for four countries: Chad, Djibouti, Eritrea and Yemen.

“Except for these four countries, the 2016 Olympic and Paralympic Games do not pose a unique or significant risk for further mosquito-borne transmissions of Zika virus in excess of that posed by non-Olympic travel,” the report from the CDC said.

Still, many countries – including the United States – are monitoring athletes for signs of Zika. The U.S. Olympic Committee said it trained team members on mosquito-bite prevention, issued them long-sleeved shirts and pants and put them in air-conditioned housing. They were also offered condoms for up to six months after the competitions.

With the conclusion of the 2016 Summer Olympics over the weekend, attention is now turning back to threat of mosquitoes within U.S. borders.

There’s some bad news on that front. A new analysis by the nonprofit group Climate Central shows that because of climate change, mosquito seasons are lengthening. According to a Capital Weather Gang report, Baltimore and Durham top the list of growing mosquito seasons, with a 37-day increase in the season of bug bites since 1980. Minneapolis’s season has grown by 34 days, Myrtle Beach’s by 34 days, Raleigh’s by 33 days and Portland’s by 32 days.

There was one bit of positive information in the report: In a few hot Southern cities in both Florida and Texas, rising extreme heat has caused the mosquito season to begin to decrease. However, these areas still have hundreds of days a year that are ideal for breeding the insects.

In Miami, unfortunately, the season has gone from 317 to 337 days, the report noted.

Florida Gov. Rick Scott, R, and Miami Beach Mayor Philip Levine, D, have mounted an aggressive mosquito-eradication campaign since the beginning of the year – using vacuum trucks to drain water in low-lying areas, filling potholes in alleys and fixing drips in beach showers.

Fauci said in the interview on Sunday that these and other mosquito-control measures may be the most effective way to minimize the impact of Zika in the United States.

“With our experience with other similar viruses like dengue, this is something that could hang around for a year or two,” he said. “Hopefully, we get to a point to where we could suppress it so that we won’t have any risk of it.”