The World Health Organisation has declared the Ebola outbreak caused by Bundibugyo virus in the Democratic Republic of Congo (DRC) and Uganda “a public health emergency of international concern”.
The WHO said that as of 16 May, eight laboratory-confirmed cases, 246 suspected cases and 80 suspected deaths have been reported in Ituri Province of the DRC across at least three health zones, including Bunia, Rwampara and Mongbwalu. Unusual clusters of community deaths with symptoms compatible with Bundibugyo virus disease have been reported across several health zones in Ituri, and suspected cases have been reported across Ituri and North Kivu.
In addition, two laboratory confirmed cases (including one death) with no apparent link to each other have been reported in Kampala, Uganda, within 24 hours of each other, on 15 and 16 May 2026, among two individuals travelling from the DRC.
“There are currently no approved Bundibugyo virus-specific therapeutics or vaccines. As such, this event is considered extraordinary,” the WHO says.
Uncertainty around spread
The WHO say the outbreak of Ebola caused by Bundibugyo virus “does not meet the criteria of pandemic emergency.”
But the organisation added that there are “significant uncertainties to the true number of infected persons and geographic spread associated with this event at the present time. In addition, there is limited understanding of the epidemiological links with known or suspected cases.”
“However, the high positivity rate of the initial samples collected (with eight positives among 13 samples collected in various areas), the confirmation of cases in both Kampala and Kinshasa, the increasing trends in syndromic reporting of suspected cases and clusters of deaths across the province of Ituri all point towards a potentially much larger outbreak than what is currently being detected and reported, with significant local and regional risk of spread.”
Neighbouring countries sharing land borders with the Democratic Republic of the Congo are considered at high risk for further spread due to population mobility, trade and travel linkages, and ongoing epidemiological uncertainty, the WHO says.
At least four deaths among healthcare workers in a clinical context, “suggestive of viral haemorrhagic fever” have been reported from the affected area, the WHO said, “raising concerns regarding healthcare-associated transmission, gaps in infection prevention and control measures, and the potential for amplification within health facilities.”
A severe and fatal form of Ebola
The WHO describes the Bundibugyo virus disease as a “severe and often fatal form of Ebola disease”. It is a zoonotic disease, with fruit bats suspected to be the natural reservoir. Human infection occurs through close contact with the blood or secretions of infected wildlife, such as bats or non-human primates, and subsequently spreads from person to person through direct contact with the blood, secretions, organs, or other bodily fluids of infected individuals or contaminated surfaces.
The incubation period for Bundibugyo virus ranges from 2 to 21 days, and individuals are usually not infectious until symptom onset. Early symptoms are non-specific, including fever, fatigue, muscle pain, headache, and sore throat, which complicates clinical diagnosis and can delay detection. These progress to gastrointestinal symptoms, organ dysfunction, and in some cases haemorrhagic manifestations. Case fatality rates in the past two Bundibugyo virus outbreaks, reported in Uganda and in DRC in 2007 and 2012, have ranged from approximately 30% to 50%.
The WHO has advised the Democratic Republic of the Congo and Uganda to activate their national disaster / emergency management mechanisms and establish an emergency operation centre, to coordinate response activities across partners and sectors to ensure efficient and effective implementation and monitoring of control measures.
The WHO says those must include enhanced surveillance including contact tracing, infection prevention and control, risk communication and community engagement, laboratory diagnostic testing, and case management. Cross-border screening and screening at main internal roads should also be introduced, and community awareness should be bolstered, it says.