How Congo's Ebola outbreak became the second-most lethal on record

The ongoing Ebola outbreak is now the second-most lethal on record and the deadliest in the history of Democratic Republic of Congo. Only the epidemic in West Africa in 2014-16 killed more people.

The grim milestone was reached on Sunday when government data ​showed that confirmed deaths topped the toll for Congo’s 2018-2020 Ebola outbreak, previously the worst the country had seen.

Delayed detection, overwhelmed surveillance teams, ‌armed conflict and a lack of vaccines and treatments for the species of the virus involved have allowed Ebola to outrun containment efforts this time.

HOW FAST IS IT SPREADING?

Health officials say the current outbreak is spreading five times faster than previous outbreaks did in Congo at this stage. There are now 4,945 cases confirmed, including 2,325 deaths, according to the latest data published on Sunday.

The 2018-2020 outbreak ​in Congo ended with 3,481 cases and 2,299 deaths recorded over two years.

It took more than 10 months to hit 2,000 confirmed cases in ​that outbreak. The current outbreak reached that figure in roughly two months.

In the West Africa epidemic, the World Health Organization recorded ⁠more than 28,000 cases and 11,000 deaths across Liberia, Guinea and Sierra Leone.

A HEAD START FOR THE VIRUS

The rare Bundibugyo species of the virus spread undetected for months ​before the outbreak was declared in May.

Reuters reported that early cases were missed, some being diagnosed as peritonitis. Local funeral practices helped the virus spread before any alarm was raised, ​and continue to undermine the response.

Health workers initially relied on tests for the wrong species of Ebola and samples sent to Kinshasa were mishandled.

A July report published in Science, a peer-reviewed academic journal, concluded that the outbreak had begun at least as early as January on the outskirts of the mining town of Mongbwalu.

SURVEILLANCE TEAMS UNABLE TO CATCH UP

World Health Organization officials estimated in July that ​around 80% of new infections emerged outside known transmission chains, suggesting most cases are identified only after the virus has spread rapidly through communities.

Health surveillance teams are overstretched, ​but undetected transmission can lead to even more cases.

The growing proportion of confirmed Ebola patients dying after an infection is an indication of persistent shortcomings in the response, experts say.

The case ‌fatality rate, ⁠as this figure is known, has risen from about 20% in early June to 47%, according to government data.

The trend does not indicate the virus has become more lethal.

The early figure was likely underestimated, while its increase highlights the fact that many cases are still being detected late, experts say.

AID CUTS AND UNPAID SALARIES

Aid cuts have hampered surveillance efforts.

USAID was awarding a five-year contract in 2025 to carry out health surveillance in Congo when the agency was abruptly shuttered, Tom Van Boven, the global health ​security team lead, told Reuters.

Reuters reported ​in June that key parts of the ⁠Ebola response were facing funding and staffing shortfalls.

As of mid-July, WHO had received less than half the funding needed to fight the eastern Congo outbreak. Health workers have also protested over unpaid salaries.

NO VACCINE, NO PROVEN TREATMENT

Unlike the more common Zaire species behind the ​2018-2020 outbreak, for which vaccines and treatments exist, there is no licensed vaccine or proven treatment for the Bundibugyo species.

Most ​vaccines developed over the ⁠past decade focused on the Zaire species.

A small number of experimental vaccines and therapies are being evaluated, while global health authorities assess whether existing Ebola treatments could offer protection. Evidence so far is limited to animal studies.

CONFLICT AND MISTRUST

The outbreak is concentrated in eastern Congo, a region affected by violence for decades, where conflict has delayed access to communities, ⁠disrupted the movement ​of personnel and supplies, and made contact tracing more difficult.

Attacks on hospitals and health teams continue and ​have put response workers at risk.

Eastern Congo sits along major trade and migration routes, with people travelling between towns, displacement camps and neighbouring countries.

Reuters reported in June on dozens of suspected Ebola-linked deaths at a displacement ​camp, raising concerns about transmission among hard-to-monitor, mobile populations.