International health experts are preparing to “surge” into West Africa to fight the raging outbreak of Ebola virus, and say they are confident they can keep it from spreading to countries like the United States and eventually stamp it out.

The Centers for Disease Control and Prevention stepped up a travel alert for West Africa Thursday, saying nonessential people should put off travel there for now. But CDC director Dr. Thomas Frieden said that was more to keep people out of the way of emergency work than to prevent the spread of Ebola.

“It is not a potential of Ebola spreading widely in the U.S. That is not in the cards,” Frieden told reporters on a conference call. “We are not telling people who are essential to leave.”

Ebola has infected 1,323 people and killed 729 people in the current outbreak, which spans Liberia, Guinea and Sierra Leone. The World Health Organization says it is still out of control in some places and announced a $100 million plan Thursday for stepping up efforts against it.

As part of the plan, CDC will send 50 people to the region over the next month, Frieden said.

“This is a tragic, painful, dreadful, merciless virus. It is the largest, most complex outbreak that we know of in history,” Frieden said. “We at CDC are surging our response along with others. Although it will not be quick and it will not be easy, we do know how to stop Ebola.”

“Although it will not be quick and it will not be easy, we do know how to stop Ebola."

As for Ebola coming to the U.S., Frieden is not overly worried.

“We have quarantine stations at all the major ports of entry,” he said. People cannot transmit Ebola to others unless they are sick, and Ebola makes you so sick that it’s pretty obvious pretty quickly, Frieden said. A traveler will be flagged by the flight crew and if someone gets sick after arrival in the U.S. they will almost certainly seek medical care.

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“Ebola poses little risk to the U.S. general population,” Frieden said. “Ebola is spread as people get sicker and sicker. They have fever and may develop serious symptoms.” Ebola doesn’t spread through the air like measles. People who get sick are family members or healthcare workers in prolonged and close contact with victims.

That's almost certainly how two Americans became infected. Dr. Kent Brantly and Nancy Writebol were caring for patients in a crowded, busy facility in Monrovia, Liberia when they were both infected. They're both now struggling for their own lives. Emory University Hospital in Atlanta said Thursday it was preparing a special isolation unit to receive a patient with Ebola disease “within the next several days” but did not say whether the patient is one of the two Americans.

“It’s not the common cold. It is not the flu. It really requires exposure to blood and bodily fluids,” said Dr. Amesh Adalja, an infectious disease physician at the University of Pittsburgh Medical Center and senior associate at the UPMC Center for Health Security.

And basic hygiene at the emergency room door or in the clinic should prevent spread there. Any U.S. intensive care unit can do it, Frieden said. “We work actively to educate American health care workers,” he said. “There is nothing particularly special about the isolation of an Ebola patient, other than it is really important to do it right.”

While hospitals in West Africa have become “amplification centers” for Ebola, that wouldn’t happen in a country with modern facilities, Frieden said. “We have strong systems to find people, if there is anyone with Ebola in the U.S. … to isolate them and to provide follow-up.”

In Africa, CDC specialists will help set up emergency operations centers to help coordinate the response. Right now, health experts say they don’t even know where outbreaks are popping up until it’s almost too late. Having a command and control center gives experts a place to gather information and to coordinate decision-making and action.

Ebola first emerged in 1976 and since then there have been two dozen outbreaks in Congo, Uganda, Gabon, Democratic Republic of Congo and Sudan. Public health experts know how to cope with it.

“They will be able to implement the tried and true activities,” said Dr. Adalja. “There is no reason that is not going to work here.”

“This is going to take at least three to six months, even if everything goes well.”

That means painstaking work of identifying cases quickly, isolating the patients so they don’t infect anybody else, and tracking down everyone they were in close contact with to watch and make sure they don’t become infected. “That is what has stopped every Ebola outbreak that has ever happened before and that is what is going to stop this Ebola outbreak,” Frieden said.

It also includes educating the public about Ebola. Ebola’s spread so badly in West Africa for several reasons: It’s never been seen there before so people don’t know what to expect and don’t understand how to stop its spread.

In addition, the countries have very weak or even nonexistent health care facilities, so patients often cannot even be diagnosed, much less isolated or treated. Healthcare workers become infected as they struggle to treat cases. And because so few people in the three countries are familiar with outside medical practices, they are suspicious of strangers coming in, wearing protective gear and telling them what to do.

So CDC, WHO and nonprofit groups must find local, trusted leaders to help them communicate the basics about the disease in a way that people will accept.

CDC experts and state health officials have years of experience of tracking down people who have been in contact with patients who have a range of infectious diseases, from Lassa fever to MERS and measles.

In fact, Lassa fever, which is similar to Ebola in many ways, is a good example of how the system does work, Adalaja said. “We have had eight importations of Lassa fever in the past few decades,” he said. “None of those cases ended up with any secondary cases. We were ready for them.”

It will take a while to put out this fire, however, Frieden cautioned.

“This is a marathon, not a sprint,” he said. “This is going to take at least three to six months, even if everything goes well.”