But U.S. officials are still working to find centers in Europe to accept Americans who need advanced treatment, seen as critical to improving odds of survival.

© Arlette Bashizi for The New York Times

Seven confirmed cases of the virus have already been reported in Kampala, the capital, but officials say the country has robust disease surveillance.

© Badru Katumba/Agence France-Presse — Getty Images

In past outbreaks, Americans exposed to the virus were sent home to be treated in state-of-the-art facilities. The Trump administration has already flown some U.S. citizens to Europe for treatment.

© Abubaker Lubowa/Reuters