The World Health Organization (WHO) has declared an Ebola outbreak in the Democratic Republic of Congo a public health emergency of international concern.
The agency said the outbreak in DR Congo's eastern Ituri province, which has seen around 246 suspected cases and 80 deaths reported, does not meet the criteria of a pandemic emergency.
But it warned it could potentially be "a much larger outbreak" than what is currently being detected and reported, with significant risk of local and regional spread.
The current strain of Ebola is caused by the Bundibugyo virus, the health agency said, for which there are no approved drugs or vaccines.
Early symptoms include fever, muscle pain, fatigue, headache and sore throat, and are followed by vomiting, diarrhoea, a rash and bleeding.
The WHO said there are now eight laboratory-confirmed cases of the virus, with other suspected cases and deaths across three health zones including Bunia the capital of Ituri province, and the gold-mining towns of Mongwalu and Rwampara.
One case of the virus has been confirmed in the capital Kinshasa, believed to be in a patient returning from Ituri.
The WHO said that the virus has spread beyond DR Congo, with two confirmed cases reported in neighbouring Uganda. Ugandan officials said a 59-year-old man who died on Thursday had tested positive.
In a statement, the Ugandan government said the patient who died was a Congolese citizen whose body has already been returned to DR Congo.
A laboratory has also confirmed an Ebola case in the eastern city of Goma, currently controlled by the M23 rebels, the AFP news agency reported on Sunday.
The WHO said the ongoing security situation and humanitarian crisis in DR Congo, combined with high population mobility, the urban location of the hotspot, and the large number of informal healthcare facilities in the region increased the risk of spread.
Countries bordering the DR Congo are considered high risk due to trade and travel.
The WHO advised that DR Congo and Uganda establish emergency operation centres to monitor, trace, and implement infection-prevention measures.
To minimise spread, the health agency said confirmed cases should be immediately isolated and treated until two Bundibugyo virus-specific tests conducted at least 48 hours apart are negative.
For countries bordering regions with confirmed cases, governments should enhance surveillance and health reporting.
The WHO added that countries outside the affected region should not close their borders or restrict travel and trade as "such measures are usually implemented out of fear and have no basis in science".
WHO director general Dr Tedros Adhanom Ghebreyesus warned there are currently "significant uncertainties to the true number of infected persons and geographic spread" of the outbreak.
Ebola was first discovered in 1976 in what is now DR Congo, and is thought to have spread from bats. This is the 17th outbreak of the deadly viral disease in the country.
There is no proven cure for Ebola, with the average fatality rate is around 50%, according to the WHO.
Africa CDC previously said it was concerned by the high risk of further spread due to the urban settings of Rwampara and Bunia, and mining activities in Mongwalu.
The health agency's executive director Dr Jean Kaseya added that "significant population movement" between the affected areas and neighbouring countries also meant regional co-ordination was essential.
Around 15,000 people have died from the virus in African countries over the past 50 years.
DR Congo's deadliest outbreak was between 2018 and 2020, during which nearly 2,300 people died.
Last year, 45 people died after an outbreak in a remote region.
Additional reporting by James Gallagher
