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. 2026 Jul 31;16:1843191. doi: 10.3389/fcimb.2026.1843191

Figure 1.

Figure 1 contains two panels summarizing country-level evidence for bovine digital dermatitis (BDD). Panel A maps 33 countries with at least one eligible primary bovine BDD source; hollow circles mark 12 countries with an explicit individual-level clinical estimate, and a Europe inset enlarges densely clustered countries. Gray does not indicate disease absence. Panel B shows the earliest and latest included-source years as evidence windows, or a gray square where only one included-source year was identified; these windows do not imply continuous surveillance. A parallel matrix identifies 15 countries with included sources reporting culture recovery, PCR/qPCR/FISH, or sequence-based characterization of BDD-associated treponemes.

Global reported distribution of bovine digital dermatitis and country-level evidence synthesis as of 31 December 2025. (A) Countries for which at least one eligible primary bovine digital dermatitis (BDD) source was identified in the curated dataset. Blue fill indicates inclusion, whereas gray indicates that no eligible country-level source was identified in the curated dataset; gray should not be interpreted as evidence that BDD is absent or that no BDD report exists for that country. Hollow circles identify countries with at least one explicit individual-level clinical estimate. An estimate was classified as individual-level when a primary source reported a clinical BDD proportion or percentage for a defined bovine study population. Herd-level positivity, hoof- or lesion-level proportions, combined lesion outcomes, lameness, serology, and pathogen-detection proportions were excluded. Because sampling frames, case definitions, and ascertainment procedures differed among studies, the markers indicate the availability of an estimate rather than nationally representative prevalence or direct cross-country comparability. (B) Country-level evidence windows and laboratory methods for BDD-associated treponemes across the 33 included countries. In the left subpanel, orange and blue circles denote the earliest and latest years among the included sources, respectively; gray squares denote a single included-source year, and horizontal segments connect the earliest and latest included years. These segments are bibliographic evidence windows and do not imply continuous surveillance, uninterrupted disease occurrence, national incidence, or endemicity. In the right subpanel, symbols indicate whether at least one included source reported culture recovery, targeted detection by PCR, qPCR, or FISH, or sequence-based characterization of BDD-associated treponemes. Sequence-based characterization includes sequencing, typing, phylogenetic analysis, or taxonomic assessment. Method categories are non-exclusive, and the absence of a symbol means only that the corresponding method was not identified in the included source set. Culture recovery does not by itself establish formal species-level assignment. Histopathology and silver staining were not included in the three plotted method categories. Literature cutoff: 31 December 2025.