(CNSNews.com) - Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, says he wouldn't be surprised if the Zika virus starts spreading within the United States this summer.
"Well, it is likely we will have what's called a local outbreak," Fauci told "Fox News Sunday."
Right now, there are more than 350 "imported cases" in the United States among people who have become infected in another country and then returned to the U.S.
"The concern is, once one comes back, would a mosquito...bite someone and then locally transmit it to someone who's never left the country? It would not be surprising at all, if not likely, that we're going to see a bit of that because we've seen similar types of things with other similar types of infection, like Dengue," Fauci said.
"We've been able to control it so that it doesn't become sustained or widespread. But the threat of at least having some local outbreak is -- is -- is likely, I would think. It's up to us now to make sure when it happens, we contain it."
Host Chris Wallace asked Fauci, "So are we talking about hundreds of cases?"
"Yes," he replied.
"Are we talking about thousands of cases?" Wallace asked him.
"No," Fauci said. "When we say local, we talk not about thousands of cases, we're talking about scores of cases, dozens of cases at the most that historically with Dengue were able to be contained."
(Dengue is spread by the same type of mosquito.)
"The other interesting thing that's important is that it is sexually transmitted. And that's another added dimension to it that is well documented now, that it can be sexually transmitted. So there's an issue there of someone who can transmit it...to someone who's not been bitten by a mosquito."
Although the Zika virus mainly threatens the brains of developing fetuses, Fauci said there are no warnings for women in this country to delay pregnancy:
"Well, right now in the United States this should not be that concerning," he said. "We do not have local transmission here. So I think the idea about people in the continental United States delaying pregnancy is not -- is not even an issue for discussion at this point.
"The issue is, when you're dealing in countries in which you have outbreaks like in South America, particularly Brazil or Puerto Rico, is a concern about what you might advise women. Right now the recommendation from the CDC (Centers for Disease Control and Prevention) are consult your physician about the kinds of options you might have.
"But a direct recommendation to delay has been given by countries. For example, El Salvador has actually said you should delay if you could. The confounding issue, Chris, about that, that's in countries in which you may not have good access to birth control, and that's one of the things that confounds that question."
"If we begin to see localize outbreaks here in the United States, besides birth control, what can men and women do to protect themselves?" Wallace asked.
"Protect yourself against mosquitos," Fauci said. "The government and local authorities can do it by cleaning up the environment to not allow mosquitos to breed. They breed in still water, pots, pans, tires or what have you. But the critical issue is, if you're in this country...stay indoors, if you can, with air conditioning and screen.
"When you're outdoors, dress in a way that covers most of your body, but use DEET-containing insect repellents. DEET at 30 percent, it's safe. It's safe for a woman that's pregnant. It's safe for babies older than six months old. We shouldn't hesitate to use insect repellant."
Adults also may be affected by the virus, Fauci said. He mentioned the possibility of adults developing Guillain-Barre syndrome; or "significant neurological damage," including meningoencephalitis, which is an inflammation of the brain and the covering around the brain; or spinal cord damage due to myelitis.
"We're starting to see them. We don't know how frequent it's going to be. So far they looks unusual, but at least we've seen them and that's concerning."
The Obama administration has asked Congress for $1.9 billion to help develop a vaccine and to fund mosquito control and educational efforts.
But House Speaker Paul Ryan (R-Wis.) says the funding will be addressed "through the regular appropriations process as the need arises."
In the meantime, the Obama administration has transferred almost $600 million from a fund used to fight Ebola to address Zika.
Fauci said the appropriations process "takes time," and when it comes to Zika, "We have to act now."
"I can't wait to start developing a vaccine. We have to do it. And in order to do it, you need money. And that's the reason for the urgency of getting that money."
Fauci said if Congress doesn't move quickly, "then what we'll have to do is to take things away from other very important areas and move it here, because we can't stop. We can't just not address this. This is really a very important thing. So we'll have to be moving money around."
Fauci told CBS's "Face the Nation" that he doesn't want to "get into the politics of it," but "from a public health and a research standpoint, we do really need that resource in order to be able to get the job done."
Republicans have said the administration's request for $1.9 billion is not sufficiently detailed.