Mystery over source of Ebola infection in Nigeria fuels concern about spread of virus

Switzerland says patient is wife of Swiss diplomat and believed to have contracted virus while travelling in Uganda

Health officials across Africa are racing to determine how Nigeria's first Ebola patient in more than a decade became infected, amid fears the outbreak could spread further after reaching a fourth African country.

The Swiss foreign ministry said on Friday the patient in Nigeria, the Ugandan-born wife of a Swiss diplomat based in Abuja, had not travelled to the Democratic Republic of Congo, where the outbreak was first detected in mid-May before spreading to Uganda, Kenya and now Nigeria. The woman was believed to have contracted Ebola while travelling with her husband in Uganda, the ministry added.