The World Health Organisation (WHO) has declared the latest outbreak of the Bundibugyo strain of Ebola virus disease in the Democratic Republic of the Congo (DRC) and neighbouring Uganda, a Public Health Emergency of International Concern (PHEIC).
The declaration follows a surge in suspected cases and deaths spreading across provincial and national borders, raising concerns among global health authorities.
WHO expressed particular concern over the Bundibugyo strain because there is currently no approved vaccine or treatment for the variant.
The agency warned that the outbreak poses a high regional risk, with infections already detected in Uganda and a linked case reaching Kinshasa, the densely populated capital of the DRC.
According to the WHO, its Director-General, Tedros Ghebreyesus, concluded that the cross-border outbreak requires the highest level of international surveillance and coordination.
The outbreak
The outbreak first came to light earlier in May after health authorities detected an unusual pattern of severe illness in parts of eastern DRC.
WHO said, “On 5 May 2026, WHO was alerted of a high-mortality outbreak of unknown illness in Mongbwalu Health Zone, Ituri Province, Democratic Republic of the Congo (DRC), including deaths among health workers.”
The agency stated that investigations traced the earliest known suspected case to a health worker.
“The first currently known suspected case, a health worker, reported onset of symptoms including fever, hemorrhaging, vomiting and intense malaise on 24 April 2026. The case died at a medical centre in Bunia,” the report added.
Following laboratory analysis, the DRC Ministry of Public Health, Hygiene and Social Welfare officially declared the country’s 17th Ebola outbreak on 15 May after the Institut National de Recherche Biomédicale (INRB) in Kinshasa confirmed Bundibugyo virus disease in eight of 13 blood samples tested.
The Bundibugyo virus is a Risk Group 4 pathogen, placing it among the world’s deadliest infectious diseases.
By mid-May, the outbreak had spread across three health zones in Ituri Province – Rwampara, Mongbwalu and Bunia – with 246 suspected cases and 80 deaths recorded.
Delayed detection
The outbreak was first reported in Ituri Province in northeastern DRC, near the borders with Uganda and South Sudan.
According to the Africa Centres for Disease Control and Prevention (Africa CDC), authorities had recorded at least 336 suspected cases and 88 deaths.
The outbreak reportedly began in Mongbwalu, a major mining town, before infected persons travelled elsewhere in search of medical treatment, unknowingly spreading the disease.
The Director-General of Africa CDC, Jean Kaseya, said delayed detection slowed the response and allowed the virus to spread undetected for weeks.
Mr Kaseya said the outbreak began in April and warned that authorities still do not fully understand the scale of transmission.
He added that many active cases remain within communities, significantly complicating containment and contact tracing efforts.
Cross-border transmission
The disease has since spread into neighbouring Uganda, further complicating containment efforts.
Uganda’s Ministry of Health confirmed its first imported case on 15 May involving an elderly man who crossed the border from the DRC.
WHO stated: “The case is an elderly man who was admitted to a private hospital on 11 May with severe symptoms and died on 14 May. A clinical sample collected was confirmed as Bundibugyo virus on 15 May 2026.”
On 16 May, Uganda confirmed a second case in the capital, Kampala, with no immediate epidemiological links to the first imported case, raising fears of wider community transmission.
A regional threat
The WHO emergency declaration, the organisation’s second-highest alert level under international health regulations, is expected to accelerate international funding and response efforts.
Mr Ghebreyesus, WHO Director-General said neighbouring countries remain vulnerable because of regional trade and population movement.
He added that neighbouring countries are “considered at high risk for further spread due to population mobility, trade and travel linkages, and ongoing epidemiological uncertainty.”
WHO also warned that official figures may underrepresent the true scale of the outbreak.
“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,” the agency said.
Implication for Nigeria
Public health experts say Nigeria remain vulnerable because of its strong travel, trade and migration links with countries in Central and East Africa, particularly through regional air routes and informal cross-border movements.
The outbreak revives memories of the country’s successful containment of Ebola in 2014 after an infected Liberian-American diplomat, Patrick Sawyer, arrived in Lagos. Through aggressive contact tracing, isolation measures and public awareness campaigns, Nigeria contained the outbreak.
Although no new case has been reported, the development could place additional pressure on Nigeria’s public health system, which is already grappling with recurring outbreaks of diseases such as Lassa fever, cholera and meningitis.
Warning against border closures
Despite declaring a global health emergency, WHO advised countries against imposing travel bans or shutting borders, warning that such measures are often ineffective.
It explained that closing official border points could force people to use informal crossings, making surveillance and disease control more difficult.
“Most critically, these restrictions can also compromise local economies and negatively affect response operations from a security and logistics perspective,” the report added.
Instead, WHO urged countries to strengthen traveller advisories, border screening, contact tracing and localised isolation measures to contain the outbreak.