The World Health Organisation, WHO has declared a “public health emergency of international concern” (PHEIC) over a fast-moving outbreak of the rare Bundibugyo strain of Ebola in the Democratic Republic of the Congo and Uganda.

It warns that the epidemic may already be far larger than currently detected and could spread rapidly across Central and East Africa.

In an extraordinary determination issued under the International Health Regulations (2005), W.H.O Director-General, Tedros Adhanom Ghebreyesus, said the outbreak constituted a serious international public health threat because of confirmed cross-border transmission, widespread uncertainty over the true scale of infections and the absence of approved vaccines or therapeutics specifically targeting the Bundibugyo virus strain.

However, WHO said the outbreak does not yet meet the threshold for a “pandemic emergency”.

As of May 16, 2026, health authorities had confirmed eight laboratory-tested Ebola cases linked to the Bundibugyo virus in Ituri Province in north-eastern DR Congo, alongside 246 suspected cases and 80 suspected deaths spread across at least three health zones including Bunia, Rwampara and Mongbwalu.

The outbreak has now spread beyond DR Congo’s borders.

Two unrelated confirmed cases were detected within 24 hours in Kampala, Uganda’s capital, involving travellers arriving from DR Congo.

Both patients were admitted to intensive care units.

WHO also disclosed that suspected cases and clusters of unexplained community deaths had been reported across Ituri and neighbouring North Kivu, fuelling fears that transmission has been occurring undetected since March.

The agency warned that the combination of high positivity rates among initial laboratory samples, mounting reports of unexplained deaths, confirmed infections in major cities and weak epidemiological links strongly suggested “a potentially much larger outbreak than what is currently being detected and reported”.
The situation has alarmed infectious disease experts worldwide because the Bundibugyo strain is significantly harder to contain than the better-known Ebola-Zaire strain that fuelled previous epidemics.

Unlike Ebola-Zaire, there are currently no approved vaccines or targeted treatments for Bundibugyo virus disease. Existing diagnostics are also less reliable at quickly detecting the strain.

Peter Piot, one of the scientists who helped identify Ebola during the first recorded outbreak in 1976 in what was then Zaire, said he was “pretty worried” that the current outbreak could become substantially larger.

Piot warned that the emergence of unrelated cases in Kampala, the spread to Kinshasa and reports of infections in Goma suggested the virus had already travelled extensively before detection.

“Once an outbreak takes hold in one of those megacities that’s going to be a nightmare, that’s my biggest concern,” Piot said, referring to the spread into densely populated urban centres.

He also expressed concern over the deaths of at least four healthcare workers in suspicious haemorrhagic fever cases, saying such fatalities are usually associated with more advanced stages of outbreaks and may indicate severe gaps in infection prevention and control measures inside health facilities.

WHO echoed those concerns, saying the deaths among health workers raised fears of hospital-based transmission and the possibility of rapid amplification within poorly equipped clinics and informal healthcare networks.

The agency said the outbreak was unfolding in a particularly dangerous context marked by insecurity, humanitarian crises, large-scale population movement and porous borders across eastern DR Congo.

Officials warned that high mobility between DR Congo and neighbouring countries through trade routes and informal crossings significantly increases the risk of further international spread.

WHO has now urged neighbouring countries to immediately strengthen surveillance systems, activate emergency response mechanisms and prepare rapid response teams capable of isolating suspected cases within 24 hours.

The organisation also advised against border closures or sweeping travel bans, insisting such measures are not scientifically justified and could instead worsen the crisis by pushing movement through unmonitored crossings.

Instead, WHO recommended enhanced exit screening at airports, seaports and major land crossings in affected countries, including temperature checks and health questionnaires for travellers.

The agency further advised that confirmed Ebola patients should not travel internationally unless medically evacuated, while contacts of confirmed cases should face restricted movement and daily monitoring for 21 days.

WHO also called for urgent international cooperation to scale up laboratory testing, surveillance, treatment capacity, contact tracing and community engagement.

Authorities in DR Congo and Uganda were instructed to activate emergency operation centres under direct government leadership, establish specialised treatment facilities and intensify public awareness campaigns involving community, religious and traditional leaders.

WHO additionally urged the rapid launch of clinical trials for experimental vaccines and therapeutics against the Bundibugyo strain.

Piot warned that weakening global health support systems caused by cuts to international aid could hamper containment efforts.

“This is a case now where foreign aid is absolutely necessary,” he said, noting that the Centres for Disease Control and Prevention had played a vital role in containing previous Ebola outbreaks.

The outbreak has revived memories of the devastating 2014 West African Ebola epidemic, which killed more than 11,000 people across Liberia, Sierra Leone and Guinea, while severely disrupting travel, trade and fragile healthcare systems across the continent.

Although DR Congo and Uganda have experienced multiple Ebola outbreaks since then, most were relatively quickly contained.

Health officials fear this outbreak may prove different because of the unusual Bundibugyo strain, evidence of undetected transmission and the appearance of cases in major cities including Kampala and Kinshasa.

The WHO declaration comes as global health authorities are also monitoring a separate hantavirus outbreak linked to a cruise ship departing from Argentina, which has reportedly killed three people.