Conflicting travel accounts

Switzerland's foreign ministry said on Friday that the Ebola patient in Nigeria - the Ugandan-born wife of a Swiss diplomat based in Abuja - had not travelled to the Democratic Republic of Congo. The ministry believes the woman contracted the virus while travelling with her husband in Uganda.

That statement directly contradicts accounts from Uganda, which previously said the woman had travelled to eastern DR Congo.

• Catherine Smallwood, a WHO Ebola incident manager in DR Congo, told a UN briefing in Geneva via video link on Friday that WHO staff there had no information showing the patient had travelled to the country.
• WHO said investigations are continuing to establish the likely source of infection for the Nigeria patient.

Investigating the route of infection

Dr Wessam Mankoula, head of emergency preparedness and response at Africa CDC, said the agency is looking into whether the patient contacted an Ebola patient in Kenya, since both travelled from Uganda's Entebbe airport on 3 October.

Smallwood said a link to the Kenya case was possible, but that officials would need to compare the timing with when the Nigeria patient's symptoms began.

Marion Koopmans, a Dutch virologist on the WHO's Ebola emergency committee, called the airport-link theory speculative: "I think that is very speculative unless there is evidence of sharing the same space in a manner that could explain that."

"Random presence at the same location, a large airport, is not a supported epidemiological link by any standard of what we currently know," she said.

Nigeria works to contain its case

Nigerian health minister Muhammad Ali Pate said the country's case remains contained and that contact-tracing was continuing. He said efforts were under way to keep the virus from reaching communities, adding that he hoped that would not happen and that work was being done to prevent it.

The wider outbreak

The outbreak was first detected in DR Congo in mid-May and has since spread to Uganda, Kenya and now Nigeria, making it the most geographically widespread in history.

• The outbreak was first announced on 15 May and has infected more than 9,500 people, killing nearly half of them.
• It is the largest and deadliest in DR Congo's history, and second only globally to the 2014-16 west Africa outbreak, which infected more than 28,600 people and killed more than 11,000.
• Uganda reported Ebola cases in May and June, and WHO declared the country Ebola-free in August.

The outbreak is caused by the rare Bundibugyo virus, which has no approved treatment or vaccine.

WHO investigations are continuing to establish the likely source of infection, while contact-tracing in Nigeria is ongoing.