Estimating the current size of the 2026 DRC Bundibugyo virus outbreak

Daily SitReps

https://insp.cd/category/actualites/

An external view aiming to support interpretation of the data provided by INSP and DRC authorities.

Model schematic

Initial model inspired by McCabe et al., 2026.

Delay estimates from 2012 Isiro outbreak

The data

Counts come from INSP situation reports (DRC). Suspected cases and deaths include non-BVD, which the model aims to account for.

Fit to the data

Transmission dynamics

Doubling time ~16 d, but very uncertain (90% 5–53) — Rₜ ≈ 1.7 (90% 1.2–2.9)

Current size

Estimated true burden ≈ 3,500 infections (90% 2,100 – 9,000)

Consistency with McCabe et al. 

Comparison to earlier versions

Reconciling different data streams

Limitations

• Based on a few weeks of data for an outbreak that started
• Several priors (delays, incubation, CFR, ascertainment) are weakly informed or imported from other outbreaks/contexts (e.g. 2012 Isiro)
• Aggregated model for the national level
• An external view of the SitRep data
• Work in progress; model and analysis drafted with an LLM under human oversight

Acknowledgements & links

With thanks to INSP and the DRC response teams, clinicians and surveillance staff whose situation reports make this work possible.

• Data from: https://insp.cd/category/actualites/
• Report and code at: https://epiforecasts.io/BVDOutbreakSize (updated regularly)

Slides at

https://epiforecasts.io/slides/bdbv_collaboratory_20260610.html