Switzerland's foreign ministry has confirmed that the woman who has tested positive for Ebola in Nigeria is the wife of a Swiss diplomat.
The woman, a 42-year-old Ugandan-born national who lives in the Nigerian capital, Abuja, tested positive for the virus on 20 October, becoming the country's first confirmed Ebola patient in more than a decade.
They both travelled to Uganda earlier this month. Her husband is currently in isolation but has not developed any symptoms, according to the Swiss foreign ministry.
The ministry told the BBC that all 25 staff at its embassy in Nigeria were in good health and did not need to isolate.
The ministry said the woman had spent about a week at a private clinic in Abuja with symptoms before her diagnosis.
It believes she contracted the virus while travelling in Uganda, although health authorities have yet to establish the source of her infection.
Uganda borders Democratic Republic of Congo, where some 4,600 have died in the country's most deadly outbreak of Ebola. Two people died in Uganda shortly after the outbreak began in May but it has been declared free of Ebola since August.
The ministry said the decision not to isolate the embassy's eight Swiss and 17 local employees was taken in consultation with Nigeria's Ministry of Health and the World Health Organization (WHO).
It added that the embassy remained open and operational, with health and safety measures in place.
The woman is receiving treatment in isolation and is showing signs of improvement, according to the WHO.
She returned to Nigeria on 3 October after spending about two and a half weeks in Uganda.
The patient did not travel to DR Congo, the Swiss government told Reuters news agency on Friday, contradicting accounts from Uganda.
She developed symptoms four days after arriving in Abuja and sought treatment at two private health facilities before testing positive for Ebola on 20 October.
Health officials are now investigating whether she may have crossed paths with a Kenyan man who died from Ebola and had travelled through Uganda's main airport on the same day.
Investigators are examining whether they could have been exposed through shared equipment or other contact, the Africa Centres for Disease Control and Prevention (Africa CDC) said on Thursday.
Dr Wessam Mankoula, the agency's head of emergency preparedness and response, said this was "one of the possible scenarios", but stressed that no link had been established.
"One of the issues we are currently investigating has been some sort of interaction between the two cases at the airport," he told journalists.
The Kenyan man had travelled from DR Congo through Uganda before arriving in Nairobi on 3 October. He died shortly afterwards, becoming Kenya's first recorded Ebola death.
Kenya has since confirmed nine infections, including the fatal case.
Although both patients passed through Entebbe airport on the same day, health officials have not established whether they met, used the same facilities or had any other contact.
Investigators are also examining whether the two infections could have a common source.
The WHO said it was too early to determine where the woman in Nigeria became infected.
"The source of exposure is still not known. The travel history of the patient is still being pieced together," said Dr Patrick Otim, a WHO emergency response official.
He said investigators had struggled to obtain a complete account of her movements because opportunities to interview her were limited while she remained in hospital.
Nigeria's Centre for Disease Control and Prevention (NCDC) said it was carrying out genomic sequencing, which could help establish whether her infection is linked to other cases.
"The investigation is reconstructing the full travel and exposure history. Genomic sequencing is given a high priority," said Dr Pavel Ursu, the WHO's representative in Nigeria.
Ugandan health officials previously said the woman had travelled to eastern DR Congo for business.
However, the WHO, Africa CDC and Nigeria's health ministry said they had not received verified information confirming that she had visited the country.
Uganda has maintained that it has no confirmed active Ebola cases and says the woman's travel through the country does not necessarily mean she contracted the virus there.
Meanwhile, Nigerian authorities are tracing more people who may have been exposed to the woman, beyond the 44 contacts initially identified.
Kenya's Health Director-General Dr Patrick Amoth said all nine confirmed infections were linked to the first patient, with no evidence of wider community transmission.
He urged the public to remain vigilant and not panic but warned: "We are not out of the woods".
He said the remaining eight patients were still in isolation and responding well to treatment.
The developments have renewed concerns about the movement of infected people across international borders, particularly between DR Congo and neighbouring Uganda, where thousands cross daily for trade, work and family visits.
Dr Otim warned that the long and porous border between the two countries made it difficult to screen everyone entering or leaving, as many people used unofficial crossing points.
The WHO's regional director for Africa, Dr Mohamed Janabi, called for "regional vigilance" and urged countries to strengthen surveillance, investigate infections and protect frontline health workers.
Ebola is a serious viral disease that spreads through direct contact with the blood or other bodily fluids of an infected person, or with contaminated objects. It does not spread through the air like flu.
The virus can cause fever, severe weakness, vomiting and diarrhoea, and can be fatal. People are not considered infectious before they develop symptoms.
Health authorities say tracing contacts quickly, isolating suspected cases and providing early treatment are crucial to preventing further transmission.
