Bundibugyo Virus

Bundibugyo ebolavirus (BDBV) is one of six recognised species in the genus Orthoebolavirus. It was first identified in 2007 during an outbreak in Bundibugyo District, western Uganda, where 149 confirmed and probable cases resulted in 37 deaths — a case fatality rate (CFR) of approximately 25%.

Bundibugyo is classified as a biosafety level 4 (BSL-4) pathogen. Infection causes severe haemorrhagic fever with symptoms including sudden fever, fatigue, muscle pain, headache, and sore throat, followed by vomiting, diarrhoea, rash, and — in fatal cases — internal and external bleeding.

Compared to Zaire ebolavirus, which has driven the largest Ebola outbreaks in history and carries a CFR of up to 90%, Bundibugyo has a lower fatality rate of 25–50%. However, lower lethality also means infected individuals may remain mobile longer, potentially increasing transmission before isolation.

There is no approved vaccine or therapeutic for the Bundibugyo strain.

Ervebo (rVSV-ZEBOV), the only WHO-approved Ebola vaccine, is specifically designed for Zaire ebolavirus — a different species. The two strains share significant genetic similarity but are immunologically distinct. Clinical trials of Ervebo did not include Bundibugyo, and cross-protection has not been established.

BDBV-specific vaccine candidates are in early-stage research but none have completed phase III trials as of mid-2026. This absence of an approved countermeasure is one reason the 2026 Bundibugyo outbreak prompted a WHO PHEIC declaration.

The 2026 Bundibugyo outbreak is the first outbreak of this strain since 2012 and the 17th Ebola outbreak recorded in the Democratic Republic of Congo since 1976.

On May 16, 2026, WHO Director-General Tedros Adhanom Ghebreyesus declared the outbreak a Public Health Emergency of International Concern (PHEIC) — the highest level of global health alert under the International Health Regulations. The declaration acknowledged both the severity of the ongoing outbreak in DRC and Uganda and the risk of further international spread.

On June 24, 2026, France reported its first confirmed Bundibugyo case — the first time this strain has ever been detected in Europe. The case was identified in Paris and is under investigation. This is being tracked live on the Ebola Tracker dashboard.