Congo's Ebola outbreak becomes largest ever of Bundibugyo strain

The Ebola outbreak in eastern Democratic Republic of Congo is now the largest ever caused by the Bundibugyo strain of the virus, and health authorities warn it is still accelerating. As of June 14, the Congolese health ministry had confirmed 782 cases and 181 deaths, with 359 people hospitalized in isolation, an increase of 106 cases and 45 deaths in just two days, according to a situational update compiled by the European Centre for Disease Prevention and Control.

Almost all of it is concentrated in one place. Ituri province, in Congo's volatile northeast, accounts for 717 of the confirmed cases across 20 health zones; North Kivu has 62 and South Kivu three. The outbreak was declared on May 15, and within days the World Health Organization had judged it serious enough to warrant its highest level of alarm.

That last point is what separates this emergency from Congo's recent ones. The vaccine that helped end the 2018-2020 outbreak in the east does not work against Bundibugyo, one of four virus species that cause Ebola disease. There is no approved treatment either; care is supportive, and control depends on the slow, dangerous fundamentals of finding cases, isolating patients, tracing contacts and conducting safe burials. The U.S. Centers for Disease Control and Prevention notes that the only two prior Bundibugyo outbreaks, in Uganda in 2007 and Congo in 2012, killed 32% and 55% of those infected.

How bad it could get

A modeling study published this month by the CDC sketches the range of outcomes, and the worst of them is alarming. If only one in five patients is isolated, the agency estimated a 65% chance that cases exceed 20,000 within three months, a trajectory that would put this outbreak in the company of the 2014-2016 West Africa epidemic, the deadliest on record, which infected more than 28,000 people and killed about 11,300.

Those projections deserve to be read for what they are: scenarios, not forecasts, built to show how much isolation rates matter rather than to predict a single number. The same modeling implies that getting more patients into care early bends the curve sharply downward. The CDC has assessed the risk to the U.S. public over the next three months as low. The harder truth is local: the official case count is widely believed to understate the real spread, and the WHO has reported a case fatality rate around 17.7% that it expects to revise as deaths predating the outbreak's declaration are confirmed.

A response fighting the terrain

Ituri is among the most difficult places in the world to run an outbreak response. Armed groups operate across the province, paved roads are scarce, and the WHO has reported security incidents at health facilities that disrupt surveillance and cut off whole areas. Congo has reimposed travel restrictions around Bunia, the provincial capital, even as the government insists the situation is under control, pointing to the 16 previous outbreaks the country has contained.

International money is starting to move. The European Union is increasing its support to the Africa CDC, with new funding for genomic sequencing, disease surveillance and training for the health workers who carry the highest risk.

Post by @hadjalahbib on the EU's Ebola response support

European Commissioner Hadja Lahbib, who visited Ituri this month, put the constraint plainly to reporters: faster diagnosis is everything. "Many patients arrive with situations that are already dire, so it's much harder to save them," she said. With no vaccine to fall back on, the response is a race between testing capacity and a virus moving through a region that was already hard to reach before anyone got sick.

This report concerns a public-health emergency. Figures cited are the most recent confirmed counts available as of June 14 and are likely to change as testing continues.