Cases in a fast-moving Ebola outbreak in the Democratic Republic of the Congo have neared 750, with 177 deaths and roughly 1,400 contacts under active tracing as of a World Health Organization press briefing Friday. The numbers already place it as the third largest Ebola outbreak ever recorded, even though the outbreak was only first reported on May 15, just over a week ago. According to Ars Technica, WHO Director-General Tedros Adhanom Ghebreyesus said the outbreak is still "spreading rapidly."
The outbreak originated in Ituri province, in the country's northeast. The earliest known suspected case involved a health worker who developed symptoms on April 24 in Bunia, the capital city of Ituri. WHO only received word of a potential outbreak on May 5, after a cluster of deadly, unidentified infections killed four health workers. By the time a WHO response team arrived on the ground, there were already 80 cases.
WHO representative Dr. Anne Ancia spoke from the DRC during Friday's briefing. She said that when officials arrived, they found the virus was "already rampant and silently disseminating for a few weeks already."
WHO officials have acknowledged that the delay in detecting and responding to the outbreak allowed it to grow to its current size. Dr. Ancia described the current situation plainly: "Now we are sprinting behind [the virus] so that we can really try to control this outbreak, and because it is still transmitting for the time being, yes, the number [of cases] will keep rising for some time until we are really able to put all the response operation in place."
A revised WHO risk assessment has moved the threat level from "high" to "very high" at the national level. Risk remains "high" at the regional level. At the global level, WHO places the risk as "low."
The virus behind this outbreak is the Bundibugyo strain of Ebola, one of the less common species in the virus family. Unlike the Zaire strain that drove the massive 2014 to 2016 West Africa outbreak, the Bundibugyo virus has no established vaccines or therapeutics approved for use against it. That leaves health workers relying entirely on active case finding, patient isolation, and contact tracing to slow transmission.
Those tools face serious obstacles in Ituri. The region is affected by armed conflict, which disrupts movement and access for health teams. Population mobility in the area is intense, which increases the risk of the virus traveling to new locations. Health systems in the province are weak, and millions of people in the surrounding area face acute hunger and depend on humanitarian assistance. Each of those factors makes it harder to find cases quickly, trace contacts reliably, and keep infected individuals isolated from their communities.
The scale of the contact tracing operation, with roughly 1,400 people currently being monitored, reflects how widely the virus has already moved through communities before detection. Health workers who were among the earliest cases suggest the virus likely entered health care settings early, where transmission risk is high and the potential to seed new chains of infection is significant.
WHO has not yet announced a specific timeline for when the outbreak might be brought under control. Dr. Ancia's assessment Friday made clear that case counts will continue rising in the near term.
