Quantification of the Animal Tuberculosis Multi-Host Community Offers Insights for Control

Abstract

Animal tuberculosis (TB) is a multi-host zoonotic disease whose prevalence in cattle herds in Europe has been increasing, despite a huge investment in eradication. The composition of the host community is a fundamental driver of pathogen transmission, and yet this has not been formally quantified for animal TB in Europe. We quantified multi-host communities of animal TB, using stochastic models to estimate the number of infected domestic and wild hosts in three regions: officially TB-free Central-Western Europe, and two largely TB-endemic regions, the Iberian Peninsula and Britain and Ireland. We show that the estimated number of infected animals in the three regions was 290,059-1,605,612 and the numbers of infected non-bovine domestic and wild hosts always exceeded those of infected cattle, with ratios ranging from 3.3 (1.3-19.6):1 in Britain and Ireland to 84.3 (20.5-864):1 in the Iberian Peninsula. Our results illustrate for the first time the extent to which animal TB systems in some regions of Europe are dominated by non-bovine domestic and wild species. These findings highlight the need to adapt current strategies for effective future control of the disease.

Keywords: disease eradication; livestock; mycobacterium bovis; stochastic models; wild animals.

Figure 1

Estimated number of infected hosts in the three geographical regions. (a) Map of the European study regions; (b) Violin plots of the posterior distribution of the number of infected hosts by region (on the square root scale) with an equal width assigned to each distribution; (c) Boxplots of the proportion of cattle, non-bovine domestic hosts, and wildlife in the infected community by region.