The leader of the small Caribbean island of St. Lucia issued an order Wednesday to immediately bar entry to travelers coming from three West African nations overwhelmed with Ebola epidemics.

The Colombian government in South America later announced it would not allow in anyone who has traveled to five African nations within the preceding four weeks.

St. Lucia Prime Minister Kenny Anthony said all visitors from Guinea, Liberia and Sierra Leone were prohibited from entering his country until the Ebola outbreak is brought under control, saying the ban will minimize chances for the deadly disease to be introduced by an infected traveler.

St. Lucia is a poor, small nation that does not have the capacity "to manage any crisis that lands on our doorstep, any crisis of that kind," Anthony said.

He said an outbreak of the virus would be devastating for the country of 200,000 people, where tourism accounts for more than 60 percent of gross domestic product.

Passengers from a fourth West African nation, Nigeria, will be required to present a "recent medical certificate" clearing them of the virus, Anthony said. Specifics of how this might work were not immediately provided.

Colombia's Foreign Ministry issued a brief statement saying the country was barring entry by any travelers requiring visas who have been in five African nations with Ebola outbreaks -- Guinea, Liberia, Sierra Leone, Nigeria and Senegal. It said the step was being taken at the recommendation of Colombia's National Institute of Health.

Haiti's prime minister put out a tweet on his official Twitter account saying the U.N. peacekeeping force in Haiti was suspending the rotation of troops from African countries as a preventative measure because of Ebola. The force has been in Haiti since 2004 after President Jean-Bertrand Aristide was ousted.

It can take up to 21 days before a person infected with Ebola starts to show symptoms that can be found in airport screening tests. During that period, an individual carrying Ebola can get on a flight and fall ill later, as happened with a Liberian who developed the disease and recently died in the U.S.

People infected with Ebola aren't contagious until they start getting symptoms, such as fever, body aches or stomach pain. There is no cure for Ebola, which can result in organ failure and massive internal bleeding. The virus can be transmitted through direct contact with the blood or secretions of an infected person or objects contaminated with the infected secretions.