WASHINGTON — A ban on travel from West Africa might seem like a simple and smart response to the frightening Ebola outbreak there. It’s become a central demand of Republicans on Capitol Hill and some Democrats, and is popular with the public. But health experts are nearly unanimous in saying it’s a bad idea that could backfire.

The experts’ key objection is that a travel ban could prevent needed medical supplies, food and health care workers from reaching Liberia, Sierra Leone and Guinea, the nations where the epidemic is at its worst. Without that aid, the deadly virus might spread to wider areas of Africa, making it even more of a threat to the U.S. and the world, experts say.

In addition, preventing people from the affected countries from traveling to the U.S. could be difficult to enforce and might generate counterproductive results, such as people lying about their travel history or attempting to evade screening.

The U.S. has not instituted a travel ban in response to a disease outbreak in recent history. The experts insist now is not the time to start, especially given that the disease is still extremely contained in the U.S. and the only people who have caught it here are two health care workers who cared for a sick patient who later died.

“If we know anything in global health it’s that you can’t wrap a whole region in cellophane and expect to keep out a rapidly moving infectious disease. It doesn’t work that way,” said Lawrence Gostin, a professor and global health expert at Georgetown University Law Center. “Ultimately people will flee one way or another, and the more infection there is and the more people there are, the more they flee and the more unsafe we are.”