WASHINGTON, D.C. (WPVI) --The spread of Zika is expected to get worse.
A National Institutes of Health official says the virus could "hang around" the United States for a year or two.
Dr. Anthony Fauci told ABC's "This Week" that other Gulf Coast states, besides Florida, are most vulnerable to the spread of the disease.
"I would not be surprised if we see cases in Texas and Louisiana, particularly now where you have the situation with flooding in Louisiana," said Fauci, director of the National Institute of Allergy and Infectious Diseases. "There are going to be a lot of problems getting rid of standing water."
The types of mosquitoes that can carry Zika can breed in just a small amount of water.
Mosquito-borne Zika cases have been found in two neighborhoods of Miami-Dade County- the Wynwood neighborhood and Miami Beach. They are the first areas on the U.S. mainland where health officials determined mosquitoes were transmitting Zika, which has spread through Latin American and the Caribbean.
The discovery last week of non-travel-related infections in Miami Beach prompted the U.S. Centers for Disease Control and Prevention to expand its travel warning for pregnant women to include the area known for nightclubs, pedestrian thoroughfares and beaches, as well as Wynwood, a neighborhood known for art galleries and boutiques.
Fauci said mosquito control is the best way to stop the spread of the Zika virus, which can cause severe birth defects, including microcephaly, in pregnant women.
"With our experience with other similar viruses like dengue, this is something that could hang around for a year or two," Fauci said. "Hopefully, we get to a point to where we could suppress it so that we won't have any risk of it."
Meanwhile the mayor of Miami Beach said city workers are doing everything in their power to go after mosquitoes in the popular tourist destination.
Mayor Philip Levine told New York radio station AM 970 that Miami Beach is running smoothly, despite the Zika concerns.
"Those 15 mosquitoes have been put under arrest. They've been apprehended. We have them in jail right now," Levine joked on "The Cats Roundtable Show."
"All kidding aside, we have contained the small little outbreak of Zika, which was very limited," he added. "It's something we're watching. It's closely contained and it certainly hasn't disrupted the business of Miami."
As for whether there will be locally-spread cases in the Philadelphia area, it is possible.
However, most experts say it would be rare to see widespread transmission.