Surveillance methodology brief, May 24, 2026
Bundibugyo virus, Democratic Republic of the Congo and Uganda, 2026
Latent Outbreak Visibility System (LOVS) applied to the 2026 BDBV outbreak. Ascertainment, detection depth, and pre-committed methodology calibration points, as of May 24, 2026.
Bottom line. Public reporting likely captures 40-46% of laboratory-confirmable cases. This brief quantifies that visibility gap and pre-commits how the method will be judged.
Why this methodology brief matters
Executive overview, May 24, 2026
What sources available for this snapshot show, and what the method estimates beneath it.
Public reporting picture
Confirmed split: 101 in DRC, 5 in Uganda. Healthcare workers among the deaths: 4.
What the method adds
Visible share
40-46%
Detection depth
Multiple rounds
Corridors
Calibration only
Supporting detail
Snapshot clocks4
- Snapshot
- 2026-05-24
- Analytic cutoff
- 2026-05-24T23:59:59Z
- Headline data as of
- 2026-05-24
- Publication cutoff
- 2026-05-24
This is a publication-state snapshot: May 23 sources are visible in the evidence trail, while the scored model endpoint remains 2026-05-24.
| Role | Data as of | Published | Retrieved | Status |
|---|---|---|---|---|
| headline_count_endpoint | 2026-05-24 | 2026-05-24 | 2026-05-25T03:58:37Z | primary_count_endpoint |
| headline_count_endpoint | n/a | 2026-05-24 | 2026-05-24T23:53:59Z | dashboard_aggregate_verified |
| corridor_source_load | 2026-05-21 | 2026-05-22 | 2026-05-23T18:36:26Z | cumulative_health_zone_table_verified |
| timeline_geography_anchor | 2026-05-21 | 2026-05-21 | 2026-05-23T19:21:01Z | official_count_geography_anchor |
Scroll horizontally to inspect the full figure.
Generated timestamp status: not_recorded.
Reporting notes
Uganda count: 5 confirmed in Kampala (1 death) per CDC Current Situation (24 May): the two imported cases plus three additional cases linked to previous cases. Earlier WHO PHEIC, Africa CDC PHECS, and WHO 20/22 May remarks reported the two imported cases. CDC reports 101 confirmed cases in DRC as of 24 May. The reported Kinshasa case tested negative on confirmatory INRB testing and is not counted as confirmed. WHO IHR temporary recommendations stated that no onward Uganda transmission among contacts was documented as of 22 May; CDC's 23 and 24 May updates carry the three linked Kampala cases.[7][2][9][8][25][26][33][35][3]
Source-conflict notes6
- Suspected count spans 395 (Africa CDC PHECS, 18 May 2026) to almost 750 (WHO Director-General Member State briefing, 22 May 2026). CDC Current Situation (23 May) reports 746 suspected DRC cases; per the higher-of-valid-primaries rule the reported endpoint defers to WHO's higher 750, with CDC's 746 and the earlier CDC 21 May 575, ECDC approximately-600, and 20 May aggregator 653 retained in the dated conflict trail.[2][3][17][14][25][33]
- Deaths span 106 (Africa CDC PHECS, 18 May 2026) to 177 suspected deaths (WHO Director-General Member State briefing, 22 May 2026). CDC Current Situation (23 May) reports a lower 176 suspected DRC deaths and one confirmed Uganda death; per the higher-of-valid-primaries rule the endpoint defers to WHO's 177, with 176 and the earlier ECDC 130 (19 May), WHO/ECDC 139 (20/21 May), the 20 May aggregator 144, and CDC 148 (21 May) retained in the conflict trail.[2][9][17][8][3][14][25][33]
- Confirmed count spans 10 (WHO PHEIC statement, 17 May 2026, case data as of 16 May: 8 Ituri + 2 Kampala; Kinshasa case deconfirmed) to 88 total country-scope confirmed cases (CDC Current Situation, 23 May 2026: 83 DRC + 5 Uganda, the latter the two imported cases plus three cases linked to previous cases). WHO's 22 May 84 (82 DRC + 2 imported Uganda) and CDC's 21 May structured tuple are retained as dated conflict evidence.[7][8][14][25][33]
- Spatial model source zones use the newest official per-health-zone confirmed-count table in the manifest: the DRC MoH SitRep MVE N 007/MVB_17/2026 PDF cumulative Table IV (data as of 21 May 2026, published 22 May 2026) lists 79 confirmed cases across Bambu, Bunia, Butembo, Goma, Katwa, Kilo, Miti-Murhesa, Mongbwalu, Nizi, Nyankunde, and Rwampara. This table supersedes WHO AFRO SitRep-01 (18 May 2026) as the zone-attributed source. CDC 21 May reports the outbreak in 11 DRC health zones in Ituri and Nord-Kivu as of 20 May. Uganda has 5 confirmed cases in Kampala including 1 death per CDC 23 May (two imports plus three cases linked to previous cases); WHO IHR temporary recommendations had documented no onward Uganda transmission among contacts as of 22 May.[31][11][8][14][25][26][33]
- Per-source archive status: all cited sources are registered in data/bundibugyo-2026/manifest.json. WHO DON 602, WHO PHEIC, WHO DG remarks, WHO IHR temporary recommendations, WHO AFRO landing page, CDC HAN, CDC Current Situation, ECDC May 19/21, and the consensus aggregator are byte-archived with SHA-256 or content-addressed raw bytes; Africa CDC, Imperial, and PAHO/WHO are hash-recorded with restricted raw publisher bytes kept private pending terms or permission confirmation.[1][7][8][25][26][4][5][14][9][17][3][2][6][13][19]
- May 21 context-only sources are archived separately from count truth. CDC traveler guidance and traveler information, the ECDC threat assessment, the PAHO/WHO epidemiological alert, WHO AFRO regional readiness reporting, and the UK support update inform preparedness and monitoring context; they do not change headline case/death counts unless they publish explicit count or geography evidence.[16][15][18][19][21][20]
Data latency35
Median lag, in days, across 35 archived editions (15 state a current-as-of date).
- Publication lag
- 0d
- Archival capture
- 1.2d
- Total visibility
- 1.8d
The trajectory chart uses the Data as of column as its x-axis when a source states one. Publication and archive capture stay visible here as latency, rather than moving the plotted epidemiologic point forward in time.
| Source | Data as of | Publication lag (d) | Archival lag (d) | Total visibility (d) |
|---|---|---|---|---|
| World Health Organization, Regional Office for Africa | 2026-05-18 | 0 | 3.8 | 3.8 |
| World Health Organization, Regional Office for Africa | 2026-05-18 | 0 | 2.9 | 2.9 |
| World Health Organization | 2026-05-21 | 0 | 2.8 | 2.8 |
| Ministere de la Sante Publique, Hygiene et Prevoyance sociale, Democratic Republic of the Congo | 2026-05-21 | 1 | 1.8 | 2.8 |
| US Centers for Disease Control and Prevention | 2026-05-19 | 1 | 1.7 | 2.7 |
| European Centre for Disease Prevention and Control | 2026-05-20 | 1 | 0.4 | 2.2 |
| European Centre for Disease Prevention and Control | 2026-05-20 | 1 | 1.2 | 2.2 |
| US Centers for Disease Control and Prevention | 2026-05-23 | 0 | 1.8 | 1.8 |
| US Centers for Disease Control and Prevention | 2026-05-22 | 0 | 1.2 | 1.2 |
| US Centers for Disease Control and Prevention | 2026-05-24 | 0 | 1.2 | 1.2 |
| European Centre for Disease Prevention and Control | 2026-05-22 | 0 | 1.2 | 1.2 |
| US Centers for Disease Control and Prevention | 2026-05-21 | 0 | 1 | 1 |
| Wikipedia contributors (consensus aggregator) | 2026-05-20 | 0 | 0.9 | 0.9 |
| World Health Organization | 2026-05-22 | 0 | 0.7 | 0.7 |
| World Health Organization | 2026-05-22 | 0 | 0.7 | 0.7 |
| World Health Organization | n/a | n/a | 5.2 | n/a |
| World Health Organization | n/a | n/a | 3.9 | n/a |
| Imperial College London, MRC Centre for Global Infectious Disease Analysis (with WHO HEP/Uganda/AFRO) | n/a | n/a | 3.8 | n/a |
| Imperial College London, MRC Centre for Global Infectious Disease Analysis (with WHO Health Emergencies Programme, WHO Uganda, WHO Regional Office for Africa) | n/a | n/a | 2.9 | n/a |
| Africa Centres for Disease Control and Prevention | n/a | n/a | 2.9 | n/a |
| European Centre for Disease Prevention and Control | n/a | n/a | 2 | n/a |
| US Centers for Disease Control and Prevention, Health Alert Network | n/a | n/a | 1.9 | n/a |
| Imperial College London, MRC Centre for Global Infectious Disease Analysis (with WHO HEP/Uganda/AFRO) | n/a | n/a | 1.8 | n/a |
| Associated Press | n/a | n/a | 1.3 | n/a |
| eNCA / AFP | n/a | n/a | 1.3 | n/a |
| International Federation of Red Cross and Red Crescent Societies | n/a | n/a | 1.3 | n/a |
| US Centers for Disease Control and Prevention | n/a | n/a | 1.2 | n/a |
| US Centers for Disease Control and Prevention | n/a | n/a | 1.2 | n/a |
| Pan American Health Organization / World Health Organization | n/a | n/a | 1.2 | n/a |
| UK Foreign, Commonwealth & Development Office / UK Health Security Agency | n/a | n/a | 1.2 | n/a |
| World Health Organization, Regional Office for Africa | n/a | n/a | 1.2 | n/a |
| US Centers for Disease Control and Prevention | n/a | n/a | 1.2 | n/a |
| US Centers for Disease Control and Prevention | n/a | n/a | 1.2 | n/a |
| Ministere de la Sante Publique, Hygiene et Prevoyance sociale, Democratic Republic of the Congo | n/a | n/a | 1 | n/a |
| World Health Organization | n/a | n/a | 1 | n/a |
Scroll horizontally to inspect the full figure.
Publication lag: current-as-of date to publication. Archival lag: publication to capture here. Total visibility lag: their sum. Editions without a stated current-as-of date show n/a.
Deep analysis
What the public numbers imply
The overview freezes what public reporting can see. This phase explains the hidden-case band, detection depth, and corridor output without turning any of them into a forecast.
Visible vs inferred burden
Trajectory views
Start with the public time series, then compare it with two latent-quantity views: ascertainment-adjusted laboratory-confirmable cases and deaths-back-projected total cases.
Scroll horizontally to inspect the full figure.
Deaths clock. The dated deaths line ends at 176 on May 21. The reconciled headline deaths input is 179 from a May 24 MoH dashboard publication with no data/report date exposed, so that value is held out of the dated death-line nodes rather than being plotted at a fabricated date.
How to read.The three lines are the dated public-reporting anchors carried in this snapshot's source trail [1][7][2][9][8][3][32][35][34][14][25][33][4][17]. Official sources are preferred for headline values; the x-axis uses each source's reported data date when available, while later snapshot/capture timing is shown separately in the data-latency table. Where a row mixes publisher cadences, the timeline refs above identify the source used for each metric. Suspected counts use the clinical case definition, deaths are attributed deaths, and confirmed are laboratory-PCR positives. The orange band sits directly above the confirmed-case endpoint and shows the inferred underlying laboratory-confirmable count after correcting only for reporting completeness. The band applies to the confirmed series alone; the method does not model an inferred range on deaths or on suspected counts. The vertical dashed arrow is the ascertainment gap, the implied count of confirmable cases not yet captured in lab data, not a forecast of future spread.
C = D · (1 + r/β)^α / CFR with r = ln(2) / τ₂ at central doubling time τ₂ = 14 d, the BDBV onset-to-death gamma from Rosello et al. 2015 eLife (α = 4.42, β = 0.388/day), and the BDBV case-fatality-ratio 95% CI from US CDC outbreak history (26–40%, spanning 55 deaths / 169 cases across the 2007-08 Uganda and 2012 DRC outbreaks). The band's width carries CFR uncertainty only; doubling-time uncertainty is presented separately in the sibling sensitivity grid. When a headline death input has only a publication clock, it is shown as a dashed interval-censored current endpoint rather than a connected dated node. The horizontal markers at 400 and 900 are the joint WHO + Imperial College MRC GIDA, May 20, 2026 total-case estimate (same death-back-projection formula plus a population-movement model), included as an external cross-check. Deaths are the input to the blue-slate back-projection; they are not drawn as a separate band on this chart.Scroll horizontally to inspect the full figure.
How to read the two bands. The orange band comes from LOVS Module C: each publicly-confirmed point divided by the reporting-completeness 50% uncertainty interval. It estimates only the laboratory-confirmable count, because the completeness posterior was fit against confirmed cases. The blue-slate band is a different quantity: total cases (clinically compatible, most never lab-confirmed). It applies Imperial Method 2, C = D · (1 + r/β)^α / CFR, with r = ln(2) / 14d, the Rosello 2015 onset-to- death gamma (α = 4.42, β = 0.388/day), and the BDBV CFR 95% CI from US CDC outbreak history (CFR_LOW = 26%, CFR_HIGH = 40%, 55 deaths / 169 cases across the 2007-08 Uganda and 2012 DRC outbreaks); upper-band uses CFR low, lower-band uses CFR high. The (1 + r/β)^α term is the gamma moment-generating function evaluated at the growth rate; it back-corrects the right-censoring bias from infections that will die but have not yet died at the observation date. Naive D / CFR omits this correction and systematically undershoots in a growing epidemic, which is why the band below is wider and higher than a naive ratio would imply. At the as-of date this yields 761–1171 total cases from 179 deaths. The latest death input is not drawn as a normal connected dated node: the dated deaths trajectory ends at 176 on May 21, while the reconciled snapshot input uses 179 deaths from a May 24 publication with no recorded data/report date. The dashed blue-slate extension marks that interval-censored current endpoint. The dashed horizontal lines at 400 and 900 mark the joint WHO + Imperial College MRC GIDA estimate from May 20, 2026, which uses the same Method 2 formula plus a population-movement model (Uganda export counts vs. observed importations). At the as-of date, the blue-slate band (761 to 1171) brackets and extends above the upper end of the Imperial range (400 to 900). The two methods do not have to agree: Imperial integrates an export-flow signal that pulls the central estimate down, while the band here only uses deaths and CFR at the central doubling time. Both methods agree the true total is several multiples of the 106 publicly confirmed cases. The Imperial "values over 1,000 not excluded" tail tracks with the upper edge of the blue-slate band. Honest caveats: (1) the band carries CFR uncertainty only; the doubling-time uncertainty (τ₂ ∈ {7, 14, 21} days per the Imperial sensitivity set) is presented separately in the sibling sensitivity grid so the two assumptions are not blurred into one width; (2) no BDBV-specific published doubling time exists; the 14-day central scenario is anchored to the 2014 West Africa NEJM range (Guinea 15.7 d, Liberia 23.6 d, Sierra Leone 30.2 d) on the fast side, consistent with Imperial's central choice; (3) the as-of completeness posterior is applied across the whole window for the orange band, assuming approximate stability; (4) both bands are latent-quantity uncertainty, not forecasts of growth.
| CFR ↓ / Doubling time → | 7 days | 14 days | 21 days |
|---|---|---|---|
| 26% | 1,880 | 1,171 | 988 |
| 33% | 1,481 | 922 | 778 |
| 40% | 1,222 | 761 | 642 |
Scroll horizontally to inspect the full figure.
How to read the grid. Each cell shows the projected cumulative-case estimate on the same denominator scale as the assumed CFR; it is not a laboratory-confirmed count. The calculation uses 179 deaths at that (CFR, doubling-time) pair and the formula total_cases = deaths × (1 + r/β)^α / CFR with r = ln(2) / doubling_time and the Rosello 2015 onset-to-death gamma (α = 4.42, β = 0.388 per day). Faster doubling (left columns) implies more cases per observed death because each endpoint death reflects a case that occurred ~11.4days ago, when the outbreak was smaller; the column corrects for right-censoring in a growing epidemic. Lower CFR (top rows) implies more total cases per observed death because each death indexes proportionally more survivors. The orange tint is a readability aid: darker cells carry larger inferred totals. The grid's spread is the honest range to hold in mind, not a rank ordering of cells by likelihood. Clock caveat: the 179-death input is anchored to source publication date 2026-05-24; the underlying data/report date is not recorded, so the grid is a snapshot-level sensitivity calculation rather than a dated trajectory point.
data/zones.json); country outlines and lakes are Natural Earth 1:10m public-domain geodata. Confirmed-case and spillover-case zones (the latter, Goma, outside the calibration set) in orange, corridor watch points in blue, the imported-case site (Kampala) in green, border-crossing watch points (Mahagi, Arua) in gray-purple, and source-review geographies in amber. Faint blue lines show review-set corridors at or above 10% adjusted 50% upper bound; the 12 pre-committed calibration corridors are dashed orange. Inline percentage chips are suppressed for this dense calibration set; exact registry intervals are in the calibration table below.Open spatial mapScroll horizontally to inspect the full figure.
How to read. Country outlines and lakes are Natural Earth 1:10m public-domain geodata, Douglas-Peucker simplified for inline display (border tolerance 0.025°, lake tolerance 0.01°). Zone markers are placed at verified WGS-84 decimal-degree coordinates from data/zones.json in the source repository; visible labels show names only to keep the dense border cluster readable. The map foregrounds 24 corridors whose adjusted 50% upper bound reaches at least 10%; 42 lower-signal corridors remain in the audit list rather than the map. The 12 pre-committed calibration corridors are highlighted. The corridor lines are watch points, not predictions of where the outbreak will spread, and not recommendations to restrict movement between these zones.
Model-abstracted zones not plotted (2)
ituri: Province-level label, not a specific point. The three affected health zones (Mongbwalu, Rwampara, Bunia) sit inside this province. The corridor model treats 'ituri' as a candidate source label; this is a known model artifact (province-level rollup) rather than a verified third source zone.bundibugyo: The pipeline emits 'bundibugyo' as both a DRC source zone and a Uganda target ('bundibugyo-uga'). The target form is a real Ugandan district (Bundibugyo District). The source form has NO verified DRC referent: BDBV is the virus name, and Bundibugyo District is in Uganda not DRC. This is a model-attribution error that we surface honestly rather than hide. Excluded from the projected map.
Analysis step 1
Ascertainment gap is wide and quantifiable
The first question is not whether the public count is wrong; it is how much of the underlying outbreak the public count can plausibly see.
Reporting completeness
39.7% to 45.9%
Drivers
Delay + context
Interpretation
Structural
The May 23 parameter audit identifies Rosello 2015 eLife [Rosello 2015] as the BDBV-specific onset-to-notification default, while retaining Camacho 2015 PLOS Currents [Camacho 2015] as the EBOV-Zaire sensitivity comparator. This visibility interval is from that Rosello-default rerun. Bundibugyo detection history is anchored to Wamala 2010 Emerging Infectious Diseases [Wamala 2010]; the Ituri operating context is described with ACLED conflict context [ACLED] and concurrent diagnostic confounders.
Scroll horizontally to inspect the full figure.
Analysis step 2
Detection occurred after multiple silent transmission rounds
The second question is timing: how much person-to-person spread likely occurred before the outbreak was visible in public reporting.
At least 3 generations
essentially 100%
Censored upper bin
96%
Chart drivers
Count + priors
Scroll horizontally to inspect the full figure.
Analysis step 3
Corridor watch list is descriptive, not a ranking
The corridor output is useful because it is pre-committed and inspectable. It is not yet useful as a ranked deployment list.
Corridors tested
66
Upper-bound cluster
1.8%-46.9%
Reader takeaway
No ranking yet
Scroll horizontally to inspect the full figure.
42 background corridors below 10% upper bound
- katwa -> kasese-uga 1.4%-4.2%
- katwa -> kampala-uga 1.4%-4.1%
- katwa -> nebbi-uga 1.5%-3.9%
- katwa -> beni-cod 1.4%-3.8%
- katwa -> bundibugyo-uga 1.2%-3.8%
- katwa -> arua-uga 1.4%-3.7%
- butembo -> bundibugyo-uga 0.7%-2.2%
- nizi -> kasese-uga 0.7%-2.1%
- bambu -> beni-cod 0.8%-2.1%
- butembo -> nebbi-uga 0.8%-2.1%
- bambu -> kampala-uga 0.7%-2.1%
- miti-murhesa -> bundibugyo-uga 0.8%-2.1%
- bambu -> kasese-uga 0.8%-2.1%
- nizi -> arua-uga 0.7%-2.1%
- kilo -> kampala-uga 0.7%-2.1%
- miti-murhesa -> kampala-uga 0.7%-2.1%
- goma-cod -> arua-uga 0.7%-2.1%
- bambu -> nebbi-uga 0.7%-2.0%
- butembo -> kampala-uga 0.7%-2.0%
- kilo -> arua-uga 0.8%-2.0%
- butembo -> arua-uga 0.7%-2.0%
- butembo -> beni-cod 0.7%-2.0%
- kilo -> nebbi-uga 0.8%-2.0%
- nizi -> kampala-uga 0.8%-2.0%
- nizi -> nebbi-uga 0.7%-2.0%
- kilo -> beni-cod 0.7%-2.0%
- goma-cod -> nebbi-uga 0.7%-2.0%
- nizi -> beni-cod 0.8%-2.0%
- butembo -> kasese-uga 0.7%-2.0%
- kilo -> bundibugyo-uga 0.7%-2.0%
- kilo -> kasese-uga 0.7%-2.0%
- goma-cod -> kasese-uga 0.7%-2.0%
- goma-cod -> kampala-uga 0.6%-2.0%
- miti-murhesa -> arua-uga 0.8%-2.0%
- bambu -> arua-uga 0.7%-1.9%
- miti-murhesa -> nebbi-uga 0.7%-1.9%
- bambu -> bundibugyo-uga 0.8%-1.9%
- miti-murhesa -> kasese-uga 0.7%-1.9%
- miti-murhesa -> beni-cod 0.7%-1.9%
- nizi -> bundibugyo-uga 0.7%-1.9%
- goma-cod -> bundibugyo-uga 0.7%-1.9%
- goma-cod -> beni-cod 0.7%-1.8%
How to read. Each bar is the method's 50% uncertainty range for the binary outcome "at least one new laboratory-confirmed case appears in the target zone within 30 days, given continued reporting in the source zone." The tight clustering of upper bounds across the review set is the headline signal: the method has enough structure to identify a surveillance review set, but not enough to rank corridors as deployment priorities. Corridors below 10% are retained for auditability rather than foregrounded.
Scroll horizontally to inspect the full figure.
How to read. Each line is one review-set corridor from the watchlist bar chart, drawn from source-zone centroid (orange dot) to target-zone centroid (blue dot) at WGS-84 decimal-degree coordinates from data/zones.json. Wider lines indicate higher watchlist-row upper bounds. The 12 mapped pre-committed calibration corridors are dashed orange; the other mapped corridors are descriptive blue. Background corridors below 10% stay in the interval chart audit list. All review-set corridors in the bar chart are georeferenced and shown here. The cluster of mapped upper bounds within the 19%–47% band shows what the bar chart says numerically: the method does not yet discriminate corridors above chance.
On Goma. Goma is a major commercial hub in North Kivu, roughly 700 km south of the outbreak core in Bunia. It already shows one laboratory-confirmed BDBV case, a traveler infected in Ituri, so it is rendered as a spillover-case site on the Outbreak geography map above. The most parsimonious epidemiological reading of that case is one of two: the virus traveled directly from the outbreak core via Goma's commercial air or lake links, or community transmission has gone undetected along the Bunia, Beni, Bundibugyo, Kasese corridor. Either reading raises surveillance priority for those intermediate zones. Goma is not in this snapshot's pre-committed corridor calibration set, because each snapshot freezes its calibration zones at build time and the 20 May snapshot was pinned without a Goma corridor. Goma should only join a later snapshot as a candidate calibration zone if that snapshot pins its own scoring contract before outcome assessment.
Calibration thread
How the method will be judged
The next pieces separate live outbreak interpretation from method evaluation: pre-committed June resolution blocks, then a retrospective backtest that says what the method is already good and bad at.
Forward scorecard
Calibration blocks carried by the May 24, 2026 snapshot
This snapshot carries 2 earlier calibration blocks unchanged. No new calibration block is pinned by this snapshot; future snapshots can append their own blocks with their own pin date, horizon, and resolution clock.
Snapshot as-of
May 24, 2026
Active blocks
2 blocks
Next scoring clock
26 days
Scroll horizontally to inspect the full figure.
| Point | Corridor | Block / design | Registry interval | Statement |
|---|---|---|---|---|
Point 1 | Bunia -> Kampala | 2026-05-20 | [22.9% to 52.3%]30d from 2026-05-20 | DetailsAt least one new laboratory-confirmed BDBV case appears in Kampala (Uganda) between 20 May 2026 and 19 June 2026, given continued reporting from Bunia Health Zone (Ituri Province, DRC). |
Point 2 | Rwampara -> Bundibugyo | 2026-05-20 | [22.7% to 52.3%]30d from 2026-05-20 | DetailsAt least one new laboratory-confirmed BDBV case appears in Bundibugyo District (Uganda) between 20 May 2026 and 19 June 2026, given continued reporting from Rwampara Health Zone (Ituri Province, DRC). |
Point 3 | Mongbwalu -> Beni | 2026-05-20 | [21.8% to 52.2%]30d from 2026-05-20 | DetailsAt least one new laboratory-confirmed BDBV case appears in Beni Health Zone (North Kivu Province, DRC) between 20 May 2026 and 19 June 2026, given continued reporting from Mongbwalu Health Zone (Ituri Province, DRC). |
Point 4 | Rwampara -> Kasese | 2026-05-20 | [20.9% to 51.5%]30d from 2026-05-20 | DetailsAt least one new laboratory-confirmed BDBV case appears in Kasese District (Uganda) between 20 May 2026 and 19 June 2026, given continued reporting from Rwampara Health Zone (Ituri Province, DRC). |
Point 5 | Bunia -> Kasese | 2026-05-21designed | [22.0% to 55.3%]30d from 2026-05-21 | DetailsCalibration point for corridor bunia -> kasese-uga. relative-high cross-border watch corridor / relative high / cross border / watchlist high |
Point 6 | Bunia -> Beni | 2026-05-21designed | [24.3% to 52.5%]30d from 2026-05-21 | DetailsCalibration point for corridor bunia -> beni-cod. relative-high in-country likely-positive control / relative high / in country / likely positive |
Point 7 | Rwampara -> Kampala | 2026-05-21designed | [21.8% to 51.5%]30d from 2026-05-21 | DetailsCalibration point for corridor rwampara -> kampala-uga. mid-band cross-border imported-case positive control / relative mid / cross border / likely positive |
Point 8 | Mongbwalu -> Kasese | 2026-05-21designed | [23.6% to 51.9%]30d from 2026-05-21 | DetailsAt least one new laboratory-confirmed BDBV case appears in Kasese District (Uganda) between 20 May 2026 and 19 June 2026, given continued reporting from Mongbwalu Health Zone (Ituri Province, DRC). mid-band cross-border watch corridor / relative mid / cross border / watchlist mid |
Point 9 | Rwampara -> Beni | 2026-05-21designed | [23.6% to 51.8%]30d from 2026-05-21 | DetailsCalibration point for corridor rwampara -> beni-cod. mid-band in-country likely-positive control / relative mid / in country / likely positive |
Point 10 | Bunia -> Arua | 2026-05-21designed | [23.6% to 52.0%]30d from 2026-05-21 | DetailsCalibration point for corridor bunia -> arua-uga. mid-band cross-border blindspot watch corridor / relative mid / cross border / blindspot watch |
Point 11 | Rwampara -> Arua | 2026-05-21designed | [22.1% to 49.4%]30d from 2026-05-21 | DetailsCalibration point for corridor rwampara -> arua-uga. relative-low cross-border likely-negative control / relative low / cross border / likely negative |
Point 12 | Mongbwalu -> Nebbi | 2026-05-21designed | [22.2% to 51.0%]30d from 2026-05-21 | DetailsCalibration point for corridor mongbwalu -> nebbi-uga. relative-low cross-border likely-negative control / relative low / cross border / likely negative |
Scroll horizontally to inspect the full figure.
Retrospective scorecard
Historical calibration on the 2014 West Africa Ebola epidemic
The method has been tested against a known historical outbreak before being used as a live calibration artifact here.
Uncertainty quality
35% tighter
Discrimination
Still chance-level
Transfer caveat
Zaire -> BDBV
The retrospective substrate is Backer and Wallinga 2016 [Backer 2016]: 62 prefectures across 74 weeks. The five evaluation checkpoints are historical West Africa backtest weeks W3, W5, W7, W9, and W11, not the live BDBV case count. The current-outbreak sections use the snapshot's reconciled confirmed count separately from this historical backtest. Three runs are reported below: without local context, with country-level local context, and with district-level local context.
| Metric | No local context | Country-level | District-level |
|---|---|---|---|
| Brier score, probability accuracy, lower is better | 0.0586 | 0.0590 | 0.0590 |
| Interval score, Bracher 2021, uncertainty quality, lower is better | 0.1002 | 0.0649 | 0.0649 |
| Calibration error, predicted vs observed frequency, lower is better | 0.0391 | 0.0500 | 0.0500 |
Scroll horizontally to inspect the full figure.
Use with care
What should change the weight you give the outputs
These sections make the blindspots visible before asking for better field inputs. The intent is not to hide uncertainty, but to show exactly which data would most improve the method.
Known caveats
Known blindspots and calibration-design notes
These are the caveats that should change how much weight a reader gives each output. The highest-impact gap is separated from secondary caveats so the audit story is easier to scan.
Source-zone validation
Still open
Calibration design
Narrow band
Attribution
Beni confounding
mongbwalu -> beni-cod resolution may reflect Beni already being active, not a clean source-to-target transmission event.Context input
Qualitative conflict
Reporting-delay prior
Single prior outbreak
These blindspots are surfaced so a responder can adjust how much weight to give each output. They are tracked in the source repository's commit history; updates will land in subsequent snapshots.
Contribution path
If you have point-of-care data
Publicly aggregated reporting can only take the method so far. The inputs below are the highest-leverage ways to sharpen it without moving sensitive data into public view.
This brief reports method estimates from publicly aggregated reporting only. Responders in the affected zones may hold data that can sharpen the method, but those data are likely privileged, time-sensitive, and not appropriate for a public repository.
Onset-date extract
A partial onset-date histogram for one health zone narrows the latent-active-chains plausibility interval. A two-column CSV with anonymous row ID and onset date is enough.
Zone-attributed counts
A {health-zone-id: confirmed_count} mapping for affected districts is the largest single discrimination lever the method is missing.
Validated centroids
For zones the snapshot may have missed, a GPS centroid plus one-sentence rationale is enough to extend the corridor model and geography visual.
Mobility or transport flow
Admin-2 call-detail-record summaries or surveyed transport flows are the documented next lever for corridor-spread discrimination.
Confirmation latency
Observed sample-to-PCR-result delays, in days, directly update the reporting-completeness prior.
Public issues are welcome for methodology. For sensitive data, coordinate a secure handoff first; contributions that land in the repository are cited and timestamped.
Audit trail
Limits, external cross-checks, and source trail
The final phase collects the hard boundaries of the brief, how LOVS uses the Imperial estimate, and the references needed to inspect the evidence chain.
May 23 methods audit
Parameter provenance and sensitivity
A source-chain pass aligned the BDBV parameter library with WHO grEPI. This section shows which inputs are now consumed in the live run, which remain sensitivity comparators, and where residual uncertainty still sits.
Reporting-delay default
8.83 d
Sensitivity comparator
4.5 d
R prior stance
0.86-1.37
Current visibility output
39.7% to 45.9%
What changes epidemiologically
What does not change yet
What already matches the existing system
Which analytic outputs consumed the latest counts
Inputs: confirmed 106; suspected 904; deaths 179
CDC confirmed/suspected counts carry a May 24 data/report date; DRC MoH deaths carry a May 24 publication clock with no dateRapportage, so deaths are a headline input but not an ordinary dated death-trajectory node.
Inputs: confirmed 106; suspected 904
Outputs: reporting completeness 50 0.397-0.459; confirmation backlog 50 462-720
Snapshot-level visibility nowcast; prior-weighted with a Beta-Binomial update from the current confirmed/suspected headline pair.
Inputs: confirmed endpoint 106; reporting completeness 50 0.397-0.459
Outputs: endpoint confirmable 50 231-267
Confirmed endpoint is dated May 24; the completeness posterior is the current snapshot posterior applied across the displayed confirmed-case series.
Inputs: deaths 179
The 179-death input updates the snapshot-level sensitivity calculation, but the source lacks a data/report date, so it must be rendered as a publication-clock endpoint rather than a connected dated trajectory point.
Inputs: confirmed 106
Transmission plausibility uses the current reconciled confirmed headline count.
Inputs: zone attributed confirmed 79; headline confirmed 106; unallocated headline confirmed 27
Blocked: No reviewed May 24 cumulative health-zone table. The DRC MoH SitRep 009 dashboard rows remain source-review because dateRapportage and the official PDF are absent at capture.
External source feed: WHO grEPI. Scope boundary: population-level epidemiological parameters only; sequence-derived or organism-level quantities are excluded from the parameter library.
Boundaries
What this brief does NOT claim
These limits are part of the product surface. They keep the page from being misread as operational guidance or a forecast.
Not a forecast
The pre-committed calibration points exist to evaluate the method's uncertainty quality at resolution. They are not surveillance recommendations and not deployment recommendations.Not a critique of the national response
Ascertainment gaps and late detection of filoviruses are intrinsic to the pathogen and to the operational context (security, displacement, co-circulating pathogens), not to the speed of any specific national response. The DRC Ministry of Public Health declared on 15 May, the Uganda Ministry of Health confirmed imported cases on 15-16 May, and INRB confirmed BDBV by PCR within days. This brief takes the national declarations as the authoritative timeline.Does not replace field epidemiology
Line-listing, contact tracing, genomic sequencing, and clinical reasoning are where outbreak control happens.Species-transfer uncertainty is not separately quantified
The historical calibration substrate is a Zaire-species outbreak; transfer to Bundibugyo carries unquantified uncertainty in the priors and the corridor model.Numbers are prior-dominated at this case count
The ascertainment and transmission-depth posteriors are heavily informed by the prior delay and transmission distributions, not by data alone. In particular, the branching-process reproduction prior is an interim modeling assumption: the May 23 parameter audit found historical BDBV model-derived R0 candidates, but not a measured 2026 R0. The detection-depth result is therefore prior-driven and not a data-driven current-outbreak BDBV estimate. Sensitivity analyses across alternative priors remain a recommended next step.Open to independent replication
Code is Apache 2.0 licensed; original authored methodology, prose, schema, and derived artifacts are CC BY 4.0; third-party source material and extracted publisher-owned tables retain their original terms. The method is described in CITATIONS.md. Independent replication is welcomed.
External cross-check
How LOVS treats the Imperial estimate
On May 20, 2026, Imperial College MRC GIDA and WHO published a joint situation estimate using two independent methods. LOVS uses that report as a methodological cross-check, not as a value to copy.
Adopted public inputs
Held separate
LOVS adds
Why the blue-slate band uses Imperial Method 2
C = D · (1 + r/β)^α / CFR, not naive D / CFR. The correction follows Nishiura's real-time CFR formulation: in a growing epidemic, some infections that will die have not died yet, so a simple deaths/CFR ratio systematically undershoots. Joint Bayesian alternatives such as Salje, Cauchemez et al. 2020 require line-list or hospital-admission time series that this public snapshot does not have.How doubling-time uncertainty is handled
τ₂ = 14 d scenario and shows τ₂ ∈ {7, 14, 21} d in the sensitivity grid instead of mixing CFR and growth-rate uncertainty into one band.Both efforts agree that the true outbreak is several multiples of public confirmations. The independent LOVS contribution is the pre-committed corridor view and its future scoring surface. Original authored methodology, prose, schema, and derived artifacts are released through the source repository; third-party source material retains publisher terms. Retrospective context comes from the West Africa 2014 outbreak.
Source trail
References
Consolidated bibliography across the brief, the LOVS pipeline priors, and the joint WHO-Imperial College MRC GIDA May 20, 2026 report referenced as an external cross-check. The full version with method-by-method attribution is in CITATIONS.md.
Frozen outbreak sources
35
Methodology priors
14
Candidate inputs
1
Downloadable appendix
XLSX
The outbreak-source list below is the frozen public-source set for this snapshot. Archive status is shown inline where available.
Primary outbreak and reporting sources
- [1]WHO Disease Outbreak News item 2026-DON602: Ebola disease caused by Bundibugyo virus, DRC and Uganda (15 May 2026), published 2026-05-15. Archive status: byte archived.
- [2]Africa CDC declaration of a Public Health Emergency of Continental Security on the Bundibugyo Ebola outbreak (18 May 2026), published 2026-05-18. Archive status: hash recorded; raw bytes private.
- [3]Wikipedia article '2026 Ituri Province Ebola epidemic', accessed 20 May 2026. Consensus aggregator cited only as an archived public signal., published 2026-05-20. Archive status: byte archived.
- [4]WHO African Region Weekly External Situation Report 01 (data as of 18 May 2026), published 2026-05-18. Archive status: byte archived.
- [5]US CDC Health Alert Network notice HAN00530: Ebola Disease Outbreak in DRC and Uganda, published 2026-05-19. Archive status: byte archived.
- [6]Imperial College MRC Centre for Global Infectious Disease Analysis (with WHO HEP, WHO Uganda, WHO AFRO). Estimation of the size of the BDBV outbreak in DRC, 18 May 2026 (superseded by the 20 May update)., published 2026-05-18. Archive status: hash recorded; raw bytes private.
- [7]WHO Director-General PHEIC determination statement (17 May 2026), published 2026-05-17. Archive status: byte archived.
- [8]WHO Director-General opening remarks at the media briefing on Ebola outbreak in DRC and Uganda (20 May 2026), published 2026-05-20. Archive status: byte archived.
- [9]European Centre for Disease Prevention and Control outbreak page: Ebola virus disease outbreak in DRC and Uganda (19 May 2026), published 2026-05-19. Archive status: byte archived.
- [10]US CDC Ebola Disease: Current Situation update (20 May 2026), reporting the 19 May structured count tuple, published 2026-05-20. Archive status: byte archived.
- [11]WHO African Region Weekly External Situation Report 01 PDF (data as of 18 May 2026), including the official affected-health-zone count table, published 2026-05-18. Archive status: hash recorded; raw bytes private.
- [12]Imperial College MRC GIDA / WHO BDBV outbreak-size estimate PDF (18 May 2026; superseded by the 20 May update), published 2026-05-18. Archive status: hash recorded; raw bytes private.
- [13]Imperial College MRC Centre for Global Infectious Disease Analysis (with WHO HEP, WHO Uganda, WHO AFRO). Estimation of the size of the BDBV outbreak in DRC, 20 May 2026 update: 400-900 cases estimated (values over 1,000 not excluded)., published 2026-05-20. Archive status: hash recorded; raw bytes private.
- [14]US CDC Ebola Disease: Current Situation update (21 May 2026), reporting 575 suspected cases, 51 confirmed cases, and 148 suspected deaths across DRC and Uganda, published 2026-05-21. Archive status: byte archived.
- [15]US CDC public information for travelers returning to the United States from DRC, Uganda, and South Sudan (21 May 2026), published 2026-05-21. Archive status: byte archived.
- [16]US CDC interim public-health assessment and traveler-management guidance for the 2026 Ebola outbreak (21 May 2026), published 2026-05-21. Archive status: byte archived.
- [17]European Centre for Disease Prevention and Control outbreak page update (21 May 2026, 18:00): WHO-derived cross-check of approximately 600 suspected cases, 139 suspected deaths, 51 DRC confirmed cases, and two imported Uganda cases, published 2026-05-21. Archive status: byte archived.
- [18]European Centre for Disease Prevention and Control threat assessment brief for the Bundibugyo Ebola outbreak (21 May 2026), published 2026-05-21. Archive status: byte archived.
- [19]PAHO/WHO epidemiological alert: Ebola Disease due to Bundibugyo virus in DRC and Uganda (21 May 2026), published 2026-05-21. Archive status: hash recorded; raw bytes private.
- [20]UK FCDO/UKHSA support and returning-worker monitoring update for the eastern DRC Ebola response (21 May 2026), published 2026-05-21. Archive status: byte archived.
- [21]WHO AFRO Zambia readiness article tied to regional Ebola preparedness (21 May 2026), published 2026-05-21. Archive status: byte archived.
- [22]Associated Press. Congo Ebola outbreak WHO spread response, published 2026-05-21. Archive status: hash recorded; raw bytes private.
- [23]eNCA / AFP. Deadly DR Congo Ebola outbreak spreads to M23-held South Kivu, published 2026-05-21. Archive status: hash recorded; raw bytes private.
- [24]International Federation of Red Cross and Red Crescent Societies. Ebola: IFRC scales up response in eastern DRC as regional risks grow, published 2026-05-21. Archive status: hash recorded; raw bytes private.
- [25]WHO Director-General opening remarks at the Member State information session on Ebola and hantavirus (22 May 2026), reporting 82 confirmed DRC cases, 7 confirmed DRC deaths, almost 750 suspected cases, 177 suspected deaths, and 2 imported Uganda cases including 1 death, published 2026-05-22. Archive status: byte archived.
- [26]WHO IHR Emergency Committee temporary recommendations for the BDBV PHEIC (22 May 2026), including DRC very-high risk, Uganda high risk, high regional risk, and no documented onward Uganda transmission among contacts, published 2026-05-22. Archive status: byte archived.
- [27]US Centers for Disease Control and Prevention. Ebola Disease: Current Situation, published 2026-05-22. Archive status: byte archived.
- [28]US Centers for Disease Control and Prevention. What Travelers Need to Know About Returning to the United States from DRC, Uganda, and South Sudan, published 2026-05-22. Archive status: byte archived.
- [29]US Centers for Disease Control and Prevention. Interim Guidance: Public Health Assessment and Management of Travelers Arriving from Affected Countries During the 2026 Ebola Outbreak, published 2026-05-22. Archive status: byte archived.
- [30]European Centre for Disease Prevention and Control. Ebola virus disease outbreak in the Democratic Republic of the Congo and Uganda, published 2026-05-22. Archive status: byte archived.
- [31]Ministere de la Sante Publique, Hygiene et Prevoyance sociale, Democratic Republic of the Congo. SitRep MVE N° 007/MVB_17/2026, published 2026-05-22. Archive status: hash recorded; raw bytes private.
- [32]World Health Organization. Ebola disease caused by Bundibugyo virus - Democratic Republic of the Congo, published 2026-05-21. Archive status: byte archived.
- [33]US Centers for Disease Control and Prevention: cdc current situation 2026 05 23, published 2026-05-23. Archive status: byte archived.
- [34]Ministere de la Sante Publique, Hygiene et Prevoyance sociale, Democratic Republic of the Congo. Sitrep 009, published 2026-05-24. Archive status: hash recorded; raw bytes private.
- [35]US Centers for Disease Control and Prevention: cdc current situation 2026 05 24, published 2026-05-24. Archive status: byte archived.
Methodology priors used by LOVS or Imperial
- [M1]Imai et al. 2020, Imperial College COVID-19 Response Team Report 1, geographic-spread extrapolation blueprint cited by the Imperial-WHO outbreak-size estimate.
- [M2]Rosello et al. 2015 eLife, Ebola virus disease in the Democratic Republic of the Congo, 1976-2014. The Isiro 2012 BDBV fit is the source of the onset-to-death gamma used in the deaths-back-projection arm and, after the May 23 parameter audit, of the onset-to-notification distribution adopted as the reporting-delay default for the Module C visibility nowcast (Camacho 2015 retained as the faster-reporting sensitivity comparator).
- [M3]Wamala et al. 2010 EID, the Bundibugyo 2007-2008 Uganda discovery outbreak; source of the BDBV case-fatality-ratio range and the inter-case interval prior.
- [M4]MacNeil et al. 2010 EID, BVD clinical features in Uganda; source of the mean incubation period and the bleeding-prevalence prior.
- [M5]Albarino et al. 2013 Virology, BDBV genomic analysis across Uganda and DRC outbreaks; consistency check for species-stable transmission dynamics.
- [M6]Faye et al. 2015 Lancet Infectious Diseases, Zaire-species serial-interval estimate referenced in the broader LOVS methodology lineage.
- [M7]Camacho et al. 2015 PLOS Currents Outbreaks, EBOV-Zaire onset-to-notification delay retained as the reporting-delay sensitivity comparator after the May 23 parameter audit.
- [M8]Choi et al. 2019 BIOMATH, historical Isiro 2012 BDBV modeling source surfaced by WHO grEPI for model-derived reproduction-number candidates; used only to cap and ground the R prior, not as a measured current-outbreak R0.
- [M9]Cori et al. 2013 American Journal of Epidemiology, the EpiEstim R_t estimation framework from the broader Ebola modeling lineage; not a source for any LOVS delay or transmission prior.
- [M10]Van Kerkhove et al. 2015 Scientific Data, Ebola epidemiological-parameter review; documents the earlier BDBV R0 evidence gap that the May 23 grEPI/Choi audit updates with capped, model-derived historical evidence.
- [M11]WHO grEPI, Global Repository of Epidemiological Parameters; used on May 23 as the external source feed for population-level BDBV parameter candidates, with organism-level quantities excluded.
- [M12]Backer and Wallinga 2016 PLOS Computational Biology, the 2014 West Africa Ebola spatiotemporal panel used as the LOVS Mode A retrospective substrate.
- [M13]Bracher et al. 2021 PLOS Computational Biology, the Weighted Interval Score used in the LOVS calibration scoring.
- [M14]ACLED conflict-event data, political-violence context used in the historical calibration substrate and referenced as qualitative Ituri/eastern DRC operating-context evidence.
Candidate inputs not yet integrated
- [C1]Wesolowski et al. 2016 Journal of Infectious Diseases, the canonical reference for mobility data (call detail records or surveyed transport flows) as a candidate next-lever input for corridor-spread discrimination; not currently used in the pipeline.