Health authorities are investigating whether the first confirmed Ebola patients in Kenya and Nigeria crossed paths at Uganda’s Entebbe International Airport, where both were reportedly present on the same day. Nigeria confirmed its first case in more than a decade on Tuesday. The patient is a Ugandan-born woman married to a diplomat based in Abuja. She vacationed in Uganda in September and returned to Nigeria earlier this month. She is receiving treatment, and 44 people who had close contact with her have been quarantined, Dr. Wessam Mankoula, head of emergency preparedness and response at the Africa Centers for Disease Control and Prevention, said Thursday. Officials are still trying to determine how she was exposed. Mankoula said investigators are examining whether there was “some sort of interaction” between her and Kenya’s first patient at Entebbe. The Kenyan patient, a businessman in his 40s who had lived in the Democratic Republic of Congo, traveled to Kenya through Uganda and died in Nairobi on Oct. 5. Kenya confirmed its first case in early October and has since reported eight additional cases, bringing its total to nine. Most of the later cases were people with close ties to the first patient. Nigeria is the fourth African country to report a case in the current outbreak, but the first in West Africa and the one farthest from the outbreak’s epicenter in eastern Congo. The outbreak began there in May. At least 4,600 people have died and about 9,700 have been infected in Congo, according to figures reported by health authorities. Uganda, which initially recorded about 20 cases, was declared Ebola-free in August. Ebola spreads through direct contact with an infected person’s bodily fluids or contaminated items. People generally are not considered infectious until symptoms begin, making the investigation into possible contact at a busy international airport a key part of tracing how the virus may have reached Nigeria.