Suspect and positive cases of bovine tuberculosis in the Republic of Croatia from 2017 to 2020

Abstract

During regular implementation of the bovine tuberculosis-free cattle herd certification programme in the period from 2017 to 2020, the Laboratory for Bacterial Zoonoses and Molecular Diagnostics of Bacterial Diseases of Croatian veterinary institute Zagreb, Croatia tested material from 161 cattle from 27 holdings in 11 counties. The material was submitted following findings of pathoanatomical changes detected in the slaughter line suggesting tuberculosis, or after a positive reaction of cows to the tuberculin comparative methods. Species from the M. tuberculosis complex (M. bovis and M. caprae) were isolated from samples of 58 bovines (36%) from 16 holdings in eight counties. M. caprae was confirmed in 55 bovines (34%) originating from 13 holdings in seven counties, and M. bovis in three bovines (2%), each from a different holding in a different county. Saprophytic mycobacteria were isolated from four bovine samples (2.5%) from three holdings in two counties, i.e., M. gordonae (1), M. celatum (1) and two unidentified species (M. sp.). Based on the obtained results, we can conclude that the main causative agent of bovine tuberculosis in the Republic of Croatia is M. caprae, which confirmed previous findings. Control of bovine tuberculosis in the Republic of Croatia is still needed and, in the future, should be further suppressed using tuberculinisation, controls on slaughter lines, depopulation of infected herds, and etiological determination of the causative agents.