Nigeria has confirmed an Ebola case in its capital, Abuja, after a woman who arrived from Uganda tested positive for the virus, the health ministry said.

The woman began showing symptoms on 7 October and was admitted to a hospital in Abuja four days later, where she was later diagnosed with Ebola. It is unclear when she arrived in Nigeria, Africa’s most populous country.

The health minister, Muhammad Pate, said authorities had begun tracing 44 people identified as contacts of the patient. “We are doing everything possible to contain this case by tracing all the contacts the individual may have had,” he said.

Uganda’s ministry of health said the patient had only transited through Uganda and that she is a Nigerian woman who had been on a business trip to Congo’s eastern region. The Nigerian authorities have not disclosed her nationality.

“Travel through Uganda does not establish that infection occurred here. The location of exposure remains under investigation,” the ministry said in a statement. The ministry insisted Uganda has “no confirmed active Ebola cases”.

Nigeria is the latest country to report an Ebola case as the outbreak spreads across the region. Kenya confirmed its first case earlier this month and has since recorded nine infections. Uganda had previously reported Ebola cases, but it later declared itself free of the virus.

Dr Jean Kaseya, the director general of the Africa Centers for Disease Control, said on X that “we are facing an extremely serious threat,” with a fatality rate of nearly 50% of cases.

“This Bundibugyo Ebola outbreak has already become the most geographically extensive in history, affecting several countries spread across three regions of Africa,” he said.

The Nigeria Centre for Disease Control said two weeks ago it was stepping up surveillance following the detection of Ebola in Kenya and strengthening the country’s preparedness for a potential outbreak.

“These efforts have focused on early detection, isolation and referral, laboratory diagnosis, infection prevention and control, contact tracing, risk communication and protection of health care workers,” the agency said.

Nigeria established an Ebola taskforce in June after the outbreak in Congo in mid-May.

The spread of Ebola beyond Congo has heightened fears among health authorities about the rapid transmission of the rare Bundibugyo virus, which has infected more than 9,500 people and killed more than 4,600 people.

The latest Ebola outbreak is the fastest-spreading on record and is on track to exceed the deadliest on record, the 11,000 people killed in West Africa’s regional outbreak between 2014 and 2016, WHO has said.