There is growing concern the Ebola outbreak in West Africa could soon go global.

This photo provided by the CDC shows an Ebola virus. U.S. health officials are monitoring the Ebola outbreak in Africa but say the risk of the deadly germ spreading to the United States is remote. (AP Photo/CDC)

The virus has killed more than 670 people in recent months and the Centers for Disease Control and Prevention has issued an alert to health care providers in New Jersey and across the country to be on the lookout for any patient showing symptoms of the disease.

U.S. health officials on Thursday warned Americans not to travel to the three African countries hit by an outbreak of Ebola: Guinea, Liberia and Sierra Leone. The last time the federal agency issued such a travel warning was in 2003 because of a SARS outbreak in Asia.

The CDC has about two dozen staffers in West Africa to help try to control the outbreak. Officials announced Thursday they will send 50 more in the next month.

Health officials say the risk of the deadly disease coming to the United States remains small, however. Earlier this week, a North Carolina hospital emergency room was briefly closed down after someone who had traveled to Africa became ill, but it turned out to be a false alarm.

Dr. Richard Porwancher of the Medical Society of New Jersey, and an infectious disease specialist at Rutgers, said if someone did arrive in the Garden State with Ebola, the chances of containing it are extremely high.

"You have to keep in mind the sanitation conditions are very different in Africa than they are here," he said. "You don't have the same sort of access to clean water, for example. Barrier precautions, meaning gloves, gowns, goggles, masks, a lot of times is not even available in health care facilities in these other countries."

While the Ebola outbreak in West Africa has been significant, Porwancher pointed out "there have not been any cases outside of Africa, there have been no cases in Europe or the United States. Historically there's been very little spread within more advanced hospitals."

He said our infection control practices are much better than anything remotely available in under-developed nations.

"I think we have to be prepared to make sure our health care facilities are aware of what to do in case someone comes from that area," Porwancher said.

He said there are five strains of Ebola, and all of them are very destructive, but they are all spread by exposure to bodily fluids, not through the air.

"Ebola has never spread the way influenza has," he said.

"The concern about flu is that there's a mutation that makes it more contagious and so far that has not happened with Ebola," he said.

Porwancher added it's important to inform the public about the topic through news stories and the CDC issuing alerts. He also stressed that any medical doctor -- if they suspect a patient has Ebola -- can reach out to the NJ Department of Health to get instructions about "what type of isolation precautions to use in someone for whom it's really suspected, how to handle any specimens and where to send those specimens."

At the White House Thursday, press secretary Josh Earnest said the U.S. is looking into Medevac options to bring two American aid workers diagnosed with Ebola back to the U.S. While the U.S. government would facilitate the response, private companies would be used.

Earnest said that type of response would be consistent with how the U.S. handled other situations, including outbreaks of SARS and drug-resistant tuberculosis, and the goal would be to ensure Americans can benefit from modern medical treatment available in the U.S.

The Associated Press contributed to this story.