The serostatus of Brucella spp., Chlamydia abortus, Coxiella burnetii and Neospora caninum in cattle in three cantons in Bosnia and Herzegovina

BACKGROUND Dairy production in Bosnia and Herzegovina exhibits limited productivity, which may partly, be explained by extensive reproductive problems of non-infectious and infectious origin. Brucella spp., Chlamydia abortus, Coxiella burnetii and Neospora caninum are common infectious causes of decreased reproductive outcomes in cattle worldwide. Little is, however, known about the disease status of herds with reduced reproductive performances. A cross-sectional study was designed to document the status of these pathogens in dairy cattle in Bosnia and Herzegovina. A total of 1970 serum samples were collected from cattle in farms located in three cantons (regions). Enzyme linked immunosorbent assays were used to screen for seropositivity against four selected pathogens. RESULTS The overall seroprevalence was estimated at both the herd level and at individual level for each pathogen. At the individual animal level, the prevalence for C. abortus, C. burnetii, N. caninum and Brucella spp. was 52.1% (95% CI: 41.2-62.7), 8.8% (95% CI: 5.3-14.2), 9.2% (95% CI: 6.0-12.3 and 0.2% (95% CI: 0.1-0.5), respectively. The corresponding estimates for herd level were 87.9% (95% CI: 82.6-91.8), 19.6% (95% CI: 14.6-25.8), 35.2% (95% CI: 28.8-42.1), and 1.5% (95% CI: 0.5-4.6). A substantial overlap was observed in the presence of N. caninum, C. abortus and C. burnetii at individual and herd level. CONCLUSION Our study demonstrated a high level of antibodies to Chlamydia abortus. Considering the association of this agent with reproductive disorders in cattle, future studies should be directed to the epidemiological traits of this infection. Additionally, the relatively high levels of exposure to C. burnetii and N. caninum found in this study highlights the need for targeted control of infectious causes of reproductive disorders in dairy cattle of the studied areas. Given the low seroprevalence, Brucella spp. does not seem to represent a problem in the reproductive health of cattle in the studied areas.