Ebola's Spread to Fourth Nation Raises Stakes as Experts Race to Pin Down Transmission Path

The Ebola outbreak has expanded to its fourth African nation as Nigeria confirmed its first case in over a decade. The new infection has intensified efforts by health authorities across the continent to determine the exact route of transmission.

The Swiss foreign ministry announced on Friday that the patient is the Ugandan-born wife of a Swiss diplomat based in Abuja. The ministry stated the woman did not travel to the Democratic Republic of Congo, where the outbreak began in mid-May. Instead, officials believe she contracted the virus while accompanying her husband on a trip to Uganda. This account conflicts with earlier reports from Uganda, which claimed the woman traveled to eastern DR Congo. A Ugandan government spokesperson told Reuters on Thursday that the country had no current Ebola cases and would publicize any new information immediately.

The World Health Organization declared Uganda Ebola-free in August after cases were reported in May and June. WHO investigations into the Nigerian case are ongoing. Catherine Smallwood, a WHO Ebola incident manager in DR Congo, told a UN briefing in Geneva that staff in the Congo had no information suggesting the patient visited the country.

The Africa Centres for Disease Control and Prevention is investigating a potential link to a patient in Kenya. Dr. Wessam Mankoula, the organization's head of emergency preparedness and response, noted that both the Nigerian and Kenyan patients traveled through Uganda's Entebbe airport on 3 October. Smallwood said a connection was possible, but officials must compare the timing with the onset of symptoms to determine if the airport was the site of infection.

Experts remain divided on the airport theory. Marion Koopmans, a Dutch virologist and member of the WHO's Ebola emergency committee, described the hypothesis as very speculative without evidence of shared space that could explain transmission. She argued that random presence at a large airport is not a supported epidemiological link under current knowledge.

Nigerian Health Minister Muhammad Ali Pate stated the case remains contained and contact tracing is active. He said officials are working to stop the virus from spreading to surrounding communities. Melaku Yirga, vice-president for Africa at Prosper Global, emphasized the need for rapid cross-border information sharing and resources for frontline workers.

The outbreak is caused by the Bundibugyo virus, which has no approved treatment or vaccine. Announced on 15 May, the epidemic has infected more than 9,500 people and killed nearly half of them. It stands as the largest outbreak in DR Congo's history and the second largest globally, following the 2014-16 west Africa epidemic.