John K Chipangura, Essa Suleman, Bruno Roque, Josef Hanekom
Canine transmissible venereal tumour (CTVT) has been reported on every continent except Antarctica, but detailed knowledge of its global prevalence remains limited. This metanalysis aims to estimate CTVT prevalence from published reports. Following the PRISMA guidelines, 380 studies were screened, and 39 studies reporting CTVT prevalence from 18 countries (1968-2025) were included. Regional and global estimates were calculated using random effects metanalysis. Thirty studies reported CTVT in population sample studies involving 7889861 dogs, with a pooled prevalence of 4% (95% CI: 0.03-0.05). Seven studies reported CTVT prevalence in dogs with reproductive disorders, with a combined sample of 5251 subjects, with a pooled prevalence of 12% (95% CI: 0.07-0.18). Despite stratification by continent, heterogeneity remained extremely high across all subgroups (I² = 99.5%, P < 0.001 in population studies and I² = 95.4%, P < 0.0001 in reproductive disorder studies), with wide prediction intervals indicating considerable uncertainty in applying a single pooled prevalence estimate to any given population. The pooled prevalence and subgroup estimates presented here should be interpreted as a broad summary of reported prevalence rather than a precise estimate of true global or regional CTVT prevalence. This study highlights the need for more structured CTVT prevalence research efforts to improve understanding of the global distribution and enable adequate resources to be allocated for developing treatment, prevention and eradication strategies of this neglected disease.