Ugandan health officials declared an Ebola outbreak in several regions in late September. Now, travelers who have been to the African country within 21 days of arriving in the U.S. will be subject to enhanced screening, according to a health alert issued Thursday by the U.S. Embassy in Uganda.

So far, cases from this outbreak have only been detected in Uganda.

Passengers from that country will be routed to one of five airports: New York's John F. Kennedy International, Newark Liberty International, Hartsfield-Jackson Atlanta International, Chicago O'Hare International or Washington D.C.'s Dulles International. The Centers for Disease Control and Prevention, the Department of Homeland Security and Customs and Border Protection are adding new screening measures at the airports.

Ebola virus disease, also referred to as EVD, is passed among humans through direct contact with an infected person's bodily fluids or objects and surfaces contaminated with such fluids.

According to the World Health Organization, the average fatality rate for Ebola is about 50%. The WHO says this outbreak appears to have been caused by Sudan virus, which it describes as a "severe, often fatal illness affecting humans." There are currently no approved vaccines or therapeutics for the Sudan ebolavirus.

The CDC recommends avoiding unnecessary travel to the affected districts in Uganda, and to avoid contact with sick people and dead bodies. Travelers should also isolate and seek medical help if any symptoms appear, such as fever, muscle pain, sore throat, diarrhea, weakness, vomiting, stomach pain, or unexplained bleeding or bruising.