What is the Bundibugyo Strain of Ebola Virus – and Can it Pass Human to Human?

What is the Bundibugyo Strain of Ebola Virus – and Can it Pass Human to Human?

The Bundibugyo strain of ebolavirus (BDBV) is one of six recognised species within the Ebolavirus genus. Discovered in 2007 in western Uganda, this distinct filovirus causes severe, a potentially fatal Viral Haemorrhagic Fever (VHF) in humans. And, yes it can pass human to human.

While genetically related to other ebolaviruses, BDBV features a unique genomic structure that alters its virulence, diagnostic profile, and response to existing medical treatments.

The Six Major Ebolavirus Strains

The genus Ebolavirus consists of six distinct species, each named after its point of origin:

• Zaire ebolavirus (EBOV): The most lethal and common strain, responsible for the devastating 2014–2016 West Africa epidemic.

• Sudan ebolavirus (SUDV): A highly virulent strain with numerous major outbreaks in East Africa.

• Bundibugyo ebolavirus (BDBV): The focus strain, known for lower average mortality but high transmissibility.

• Taï Forest ebolavirus (TAFV): Discovered in Côte d’Ivoire; has only caused a single non-fatal human case.

• Reston ebolavirus (RESTV): Found in the Philippines; infects primates and pigs but does not cause symptomatic disease in humans.

• Bombali ebolavirus (BOMV): Identified in Sierra Leone bats in 2018; its potential to infect humans remains unknown.

Transmission and Clinical Symptoms

BDBV is a zoonotic pathogen, probably originating in fruit bats. Spillover occurs when humans handle infected wildlife. Human-to-human transmission then drives outbreaks via direct contact with the blood, secretions, or bodily fluids of symptomatic individuals. Following a 2 to 21-day incubation period, patients suffer an abrupt onset of fever, muscle aches, and fatigue, which frequently escalates to severe vomiting, diarrhea, and internal or external hemorrhaging.

Outbreaks and Mortality Rates

Historically, BDBV exhibits a lower case fatality rate (CFR) than the Zaire strain, which can reach 90%. During the initial 2007 Uganda outbreak, BDBV had a CFR of approximately 25% across 149 cases. However, a subsequent 2012 outbreak in the Democratic Republic of the Congo recorded a 51% mortality rate. This variance demonstrates that BDBV remains highly dangerous and unpredictable, depending heavily on local healthcare infrastructure.

Diagnosis, Treatment, and Prevention

Early diagnosis is challenging due to symptom overlap with malaria and typhoid, requiring confirmation via RT-PCR or ELISA testing. Because BDBV is genetically distinct, the highly effective Zaire-specific therapies—including the Ervebo vaccine and monoclonal antibodies like Inmazeb—do not offer cross-protection. Consequently, management relies strictly on aggressive supportive fluid therapy and rigorous infection control protocols to prevent further spread.