The Biden administration will begin redirecting U.S.-bound travelers who had been to Uganda within the previous 21 days to five major American airports to be screened for Ebola as public health officials sent an alert to health care workers.

The U.S. Centers for Disease Control and Prevention (CDC) on Thursday issued an alert to health care workers to raise awareness about the outbreak but said there were currently no suspected or confirmed U.S. Ebola cases from the Sudan strain, which is behind the latest Uganda infections.

According to Uganda's Health Ministry at least nine people had died of the disease in Uganda by October 3. Authorities in the east African nation announced the outbreak of the deadly hemorrhagic fever on September 20. There are 43 total cases, including the deaths.

U.S. screening began Thursday at the airports but the funneling requirements are expected to take effect within the coming week or so, a source told Reuters.

"Out of an abundance of caution (CDC) and the Department of Homeland Security (DHS) Customs and Border Protection (CBP) will apply new layers of screening at these five U.S. airports in response to the Ebola outbreak in Uganda," the U.S. Embassy in Uganda said

Travelers from Uganda need to arrive at New York-John F. Kennedy, Newark, Atlanta, Chicago O'Hare or Washington Dulles airports for screening. There is no approved vaccine for the Sudan strain of the disease, triggering fears of a major health crisis in the country of 45 million people.

Two sources said about 140 people who had recently been in Uganda arrive daily in the United States, with 62% landing at one of those five airports. Officials will conduct a temperature screening, ask health questions and report arrivals to local health departments.

Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, said the CDC's health alert is an important message to both the public health and the medical community that they should be prepared for possible cases in the United States, as happened in the 2014-2016 Western Africa outbreak.

"We can handle Ebola safely in the hospital setting and provide best care to the patient, but you have to be aware that it might even be a possibility," he said, referring to the 2014 incident in which a traveler from Liberia was evaluated initially at a hospital in Dallas and was turned away.

That patient was not admitted until two days later, when he arrived at the hospital by ambulance, potentially exposing emergency responders to the deadly virus.

The U.S. Embassy in Uganda said Thursday "the risk of Ebola domestically is currently low," adding "enhanced screening applies to all passengers, including U.S. citizens, lawful permanent residents, and visa holders (to include diplomatic and official visas)."

On Wednesday, Health and Human Services (HHS) Secretary Xavier Becerra spoke with Ugandan Health Minister Jane Aceng Ocero to discuss Ebola and U.S. efforts "to support Uganda throughout this challenging period," HHS said.

On Saturday, a Tanzanian doctor working in Uganda who contracted Ebola has died, the first health worker killed by the disease in the latest outbreak in the country, Uganda's health minister said.