Bovine tuberculosis trends in Wales between 2010 and 2021

Background: Bovine tuberculosis (bTB) is the most important animal health concern in Wales. Annual testing across all cattle herds in Wales commenced in 2010. In 2017, a new geographic division of Wales was conceived, with bespoke cattle controls and eradication milestones reflecting the geographical heterogeneity of bTB distribution. Methods: This observational study uses descriptive analysis and Poisson regression modelling to analyse bTB surveillance data from all herds in Wales. Results: Since 2010, there has been a significant decrease (p < 0.0001) in bTB incidence (8.6%‒6.3%) and plateauing prevalence across Wales. Conversely, there has been an increase in bTB incidence and prevalence in discrete areas. Recurrence and persistence remain important drivers of bTB infection. One of the sharpest declines in bTB incidence was observed in an intensive action area where enhanced cattle control and wildlife vaccination were implemented in an area of high bTB prevalence. Increased herd size, dairy herd type and herd location are important risk factors affecting the rate of bTB incidents in Wales. Limitations: This study includes data from Wales only. Conclusions: Improvements in trends of bTB occurred from 2010 to 2021, but the spatial variations described in this paper support the continued need for regionally adapted surveillance and control measures.