Seroprevalence of Leptospira Hardjo in the Irish suckler cattle population

摘要

Background: Prior to the present study, the seroprevalence of leptospirosis in Irish suckler herds was unknown. In this study, we describe the herd and animal-level prevalence of Leptospira Hardjo infection in the Irish suckler cattle population. Forthe purposes of the study, the 26 counties of the Republic of Ireland were divided into 6 regions from which a representative number of herds were selected. A herd was considered eligible for sampling if it was not vaccinating against leptospirosis and if it contained > 9 breeding animals of beef breed > 12 months of age. In total, 288 randomly selected herds were eligible for inclusion in the seroprevalence dataset analysis. Serological testing was carried out using a commercially available monoclonalantibody-capture ELISA, (sensitivity 100%; specificity 86.67%).Results: Herds were categorised as either "Free from Infection" or "Infected" using the epidemiological software tool, FreeCalc 2.0. Using this classification, 237 herds were "Infected" (82.29%). The South West and South East regions had the highest herdprevalence. The regional effect on herd prevalence was largely mirrored by breeding herd size. A true animal-level prevalence of 41.75% was calculated using the epidemiological software tool, TruePrev. There was a statistically significant regional trend, with true prevalence being highest in the South East (P<0.05). The median Breeding Herd Size (BHS), when categorised into quartiles, had a statistically significant influence on individual animal true seroprevalence (P< 0.001); true seroprevalence increased with increasing BHS. Conclusions: Leptospirosis is a widespread endemic disease in the Republic of Ireland. It is possible that economic losses due to leptospirosis in unvaccinated Irish suckler herds may be underestimated.