The United States on Thursday announced stricter screening for people who traveled to Uganda because of an Ebola outbreak in the African country.

Beginning Friday, the State Department said, all air travelers entering the United States who have been in Uganda in the 21 days prior to arrival must go to one of five designated airports for screening by the Centers for Disease Control and Prevention (CDC ) pass through US Customs and Border Protection.

The airports are in New York, Newark, Atlanta, Chicago and Washington.

The move comes after the CDC issued an Ebola virus disease (EVD) alert after the Ugandan Health Ministry reported an outbreak in Mubende district on September 20.

On Wednesday, the World Health Organization announced that there were 63 confirmed and probable Ebola cases and 29 deaths in Uganda.

The CDC said the outbreak was limited to five districts in central Uganda and had not reached the capital, Kampala, or the key travel hub of Entebbe.

As of Thursday, “no suspected, probable, or confirmed EVD cases related to this outbreak have been reported in the United States or any other country outside of Uganda,” the CDC said.

There are no direct flights from Uganda to the United States. However, the CDC said it is important to screen travelers who have been to Uganda to prevent the spread of the disease.

In 2014, the United States implemented rigorous screening procedures following a severe Ebola outbreak in Africa.

Eleven people were treated for the disease in the United States, two of whom died. Most of those infected were medical workers in West Africa.