Health officials are investigating whether Ebola patients in Kenya and Nigeria crossed paths at Uganda's main airport as conflicting accounts cloud the source of one infection.

The first confirmed Ebola patients in Kenya and Nigeria may have crossed paths at Uganda's Entebbe International Airport, according to African health officials, as new information from Switzerland contradicts Uganda's account of the Nigerian patient's travel history.

Uganda, a country reporting no active Ebola infections, has become a focus of investigations into cases thousands of kilometres apart.

Uganda insists that it has no confirmed active cases of the deadly virus. Yet health authorities in Kenya and Nigeria are investigating Ebola infections involving people whose travel histories or contacts are connected to the East African nation.