A Look at Major Ebola Outbreaks and When the Disease Was First Identified

The World Health Organization (WHO) has declared the current Ebola outbreak in Congo a public health emergency of international concern, with 600 suspected cases and 130 deaths. The outbreak, caused by the rare Bundibugyo virus, has also spread to neighboring Uganda, marking the first time this strain has been reported outside Congo since its initial identification in Uganda in 2007. Ebola disease is caused by a group of viruses, including Ebola, Sudan, and Bundibugyo strains, with fatality rates ranging from 25% to 90%. Transmission occurs through contact with infected body fluids or contaminated surfaces, while fruit bats are believed to be the natural hosts. Symptoms include fever, fatigue, gastrointestinal issues, and bleeding, appearing 2 days to 3 weeks after exposure. The worst Ebola outbreak in history occurred between 2013 and 2016 in West Africa, infecting over 28,000 people and killing more than 11,000 across Guinea, Liberia, and Sierra Leone. The outbreak began in southeastern Guinea when a child, later dubbed 'patient zero,' came into contact with infected fruit bats. Congo experienced its second-largest outbreak from 2018 to 2020, with over 3,400 cases and 2,200 deaths in North Kivu, South Kivu, and Ituri provinces, later spreading to Uganda. This outbreak was caused by the Ebola virus, not the Bundibugyo strain currently affecting the region. Congo has faced multiple Ebola outbreaks, including one as recent as late 2025, with the 2007-2008 Bundibugyo strain outbreak in Uganda resulting in 131 cases and 42 deaths. Approved vaccines and treatments exist only for the Ebola virus, not the Sudan or Bundibugyo strains.