Explainer-What Do We Know About the Bundibugyo Strain of the Ebola Virus?

The World Health Organization (WHO) declared a public health emergency of international concern on May 18 due to an outbreak of the rare Bundibugyo strain of Ebola, primarily affecting the Democratic Republic of Congo (DRC) and Uganda. As of May 18, authorities reported over 100 suspected deaths and nearly 400 suspected infections, marking the strain’s reemergence after outbreaks in Uganda (2007–2008) and the DRC (2012). The Bundibugyo strain is one of four Ebola species, with a fatality rate of 30–40%, lower than the Zaire strain’s up to 90%. Transmission occurs through direct contact with bodily fluids from infected humans or animals, posing high risks for healthcare workers. A U.S. doctor in the DRC was infected during the current outbreak, highlighting the strain’s ongoing threat. No approved vaccines or drugs specifically target Bundibugyo, though experimental treatments like Merck’s Ervebo, Mapp Biopharmaceutical’s MBP 134, and NanoViricides’ NV-387 show potential. A Chinese mRNA vaccine demonstrated promise in mice but remains untested in primates. Current response efforts focus on public health measures, including rapid case detection, isolation, contact tracing, and safe burials—strategies critical in controlling the 2014–2016 West Africa Ebola epidemic. Diagnostic challenges worsened initial response times, as standard tests failed to detect Bundibugyo, leading to false negatives. Dr. Matthew Kavanagh of Georgetown University noted the delay allowed the virus to spread via transport routes and cross borders. The WHO emphasizes the urgency of deploying accurate testing and public health interventions to curb the outbreak’s expansion.