Fighting Zika virus in US

The head of the CDC testified on Capitol Hill Thursday, along with other experts about what the continental United States can expect with the Zika virus and how to protect people.

"We will undoubtedly see many travelers returning to the U.S. with Zika," said CDC Director Dr. Tom Frieden.

Forty-million Americans travel from the U.S. to Zika-affected areas every year, officials say.

Pregnant women have been advised not to go for now due to growing evidence the mosquito-borne virus can cause microcephaly - babies born with abnormally small heads and affected brain development.

As for women who plan to become pregnant in the future, Dr. Frieden says, "if this behaves like other viruses, infection with Zika before pregnancy would not have an impact on subsequent pregnancies."

But he says because we're still learning about the virus, there's no definitive answer.

In the past, Zika was considered a nuisance virus. This outbreak sparks greater concern.

Still, four out of five people infected will have no symptoms or just mild symptoms.

A small percentage of cases have possibly been linked to Guillain-Barr syndrome, which causes temporary paralysis.

Today's subcommittee meeting also reviewed President Obama's request for $1.8 billion in emergency funding to fight Zika.

The money will go toward developing a better lab test to detect the virus, mosquito-control programs and to create a vaccine.

"I can't guarantee when we will have the vaccine, but I can tell you we got a good head start because of years of work," said Dr. Anthony Fauci, National Institute of Health.