Ugandan authorities did not initially detect an Ebola outbreak because patients weren't showing typical symptoms of the lethal virus, the nation's health minister told CNN on Sunday.

Patients had fevers and were vomiting, but did not show other typical symptoms like hemorrhaging, Health Minister Dr. Christine Ondoa said.

A team made up of personnel from the Centers for Disease Control and Prevention, the Ugandan health ministry and the World Health Organization early Monday were in Kibaale, a district in the midwestern part of the landlocked central African nation, WHO said in a statement.

Medecins Sans Frontieres, also known as Doctors Without Borders, also is involved in setting up an "isolation center" at Kibaale's hospital.

National health authorities say the outbreak has infected at least 20 people, of whom 14 have died. Nine of the deaths were from a single household in the village of Nyanswiga, according to WHO.

A medic who was treating victims is among the dead, Ondoa said.

Officials are trying to determine the extent of the outbreak, CDC spokesman Tom Skinner said Sunday. The Atlanta-based organization was sending about five people to join a group of CDC staffers who are permanently based in Uganda, according to the spokesman.

"These outbreaks have a tendency to stamp themselves out, if you will, if we can get in and ... stop the chain of transmission," he said.

Ondoa described the Ebola-Sudan strain detected as "mild" compared to other types of Ebola, noting that victims' lives can be saved with intervention.

The cases have emerged in Kibaale, where a national task force had been mobilized in an effort to combat the outbreak.