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Pandemics and Biosecurity
3OCT

Ebola passes 1,000 cases in DRC

3 min read
13:42UTC

WHO bulletin DON605 logged 1,040 Bundibugyo Ebola cases and 241 deaths on 29 May, up from 831 and 186 eight days earlier. Laboratory-confirmed cases jumped 58%, from 85 to 134.

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Key takeaway

Bundibugyo Ebola has passed 1,040 cases and 241 deaths, with confirmed cases up 58% in eight days.

The World Health Organization published Disease Outbreak News bulletin DON605 on Friday 29 May, recording 1,040 total Bundibugyo Ebola cases and 241 deaths in the Democratic Republic of Congo and Uganda⁠1. The WHO is the United Nations health agency coordinating the international response; Disease Outbreak News is its formal channel for reporting verified outbreak data. Eight days earlier, DON603 had logged 831 cases and 186 deaths, so the burden rose roughly 25% in cases and 30% in deaths in a single week.

The sharpest movement was in laboratory-confirmed cases, which climbed from 85 to 134, a 58% rise, with confirmed deaths up from 10 to 18. Confirmed numbers grew faster than total numbers partly because testing caught up after the 17 May emergency declaration, so some of the jump reflects faster case-finding rather than faster transmission. The outbreak is centred on Ituri Province in north-eastern DRC, the zone bordering Uganda.

Bundibugyo ebolavirus is one of six Ebola species and last caused a large outbreak in Uganda in 2007. The human stakes sit in the total burden, not the headline percentage: 241 people have now died, and 906 of the 1,040 cases are still awaiting laboratory confirmation, a backlog that keeps the true picture ahead of the record.

Deep Analysis

In plain English

Ebola outbreaks grow in two separate counts: total suspected cases (anyone with fever and Ebola symptoms) and laboratory-confirmed cases (people where a blood test came back positive). The WHO bulletin of 29 May shows 1,040 total suspected cases but only 134 confirmed ones. That gap matters because the confirmed figure is what gets counted as the official outbreak total for international purposes. The jump of 58% in confirmed cases between 21 and 29 May happened partly because more lab tests are now being processed, and partly because the virus was already spreading in communities before the outbreak was formally identified in early May. Think of it like turning on a light in a dark room: the cases were always there; the light just revealed them. Ituri Province, where almost all cases are concentrated, is a remote part of north-eastern Democratic Republic of Congo. The roads are poor and armed groups are active in the area, making it hard for health workers to reach sick people or trace their contacts.

Deep Analysis
Root Causes

The nine-day lag between the 5 May WHO signal and the 14 May INRB species confirmation reflects a structural bottleneck in the DRC reference laboratory system: INRB in Kinshasa is the sole body certified to confirm Ebola species in DRC, and sample transport from Ituri Province requires cold-chain logistics across 2,000 km of poorly maintained roads. The Ituri provincial health system lacks a BSL-3 laboratory capable of running filovirus PCR assays independently.

A second structural cause is low contact-tracing coverage: DON603 (21 May) recorded only 21% of named contacts being followed up, a direct consequence of insecurity from ADF and CODECO armed-group activity in the Djugu territory at the outbreak's core.

The Tom Frieden-originated 7-1-7 benchmark (seven days to detect, seven days to notify, seven days to respond) requires a functional community health worker system and safe access to index patients' contacts. Both conditions were absent for at least six weeks of pre-detection transmission.

What could happen next?
  • Risk

    A 25% total-case rise in eight days, combined with only 21% contact-tracing coverage, indicates the transmission chain is ahead of the surveillance and isolation effort.

  • Consequence

    At the current seven-day doubling trajectory for confirmed cases, the outbreak could exceed 2,000 total cases within three to four weeks without a step-change in containment.

Sources:World Health Organization
Mentions:World Health Organization →Ituri Province →DON 600 →Inmazeb →Uganda →Africa CDC →PHEIC →Neil Ferguson →Anne Cori →Ebanga →Imperial College London →Ervebo →Jean Kaseya →Zaire ebolavirus →United Nations →CDC →DR Congo →Bundibugyo ebolavirus →Tom Frieden →Republic of Congo →
First Reported In

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Causes and effects
Caused by
WHO declares Ebola PHEIC, no committee
The 17 May PHEIC declaration triggered accelerated case-finding which partly drove the 58% confirmed-case rise recorded in DON605.
Occurred 17 May 2026
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Bundibugyo Ebola: 831 cases, 186 dead
DON603's 831/186 baseline is the starting point from which DON605's 1,040/241 total is measured.
Occurred 21 May 2026
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This Event
Ebola passes 1,000 cases in DRC
Total burden has crossed 1,000 cases and 241 deaths, and the confirmed-case curve is still climbing eight days on.
Led to
WHO cuts the count, cases keep climbing
DON606's confirmed-only count of 534 follows directly from the 1,040 total-cases figure in DON605 which included suspected cases later cleared from the backlog
Occurred 8 Jun 2026
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Ebola model puts the fork at 20% isolation
CDC MMWR modelling was calculated against the corrected confirmed-only baseline that superseded the DON605 1,040-case count
Occurred 5 Jun 2026
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