Investigation of leptospirosis as a cause of abortion in cattle and sheep in the Republic of Ireland

Abstract Background Sheep and cattle are considered maintenance hosts for Leptospira interrogans serovar Hardjo-prajitno and Leptospira borgpetersenii serovar Hardjo-bovis in Ireland, where the disease is endemic in these species. The infection can lead to impaired fertility, abortions, neonatal deaths and decreased milk production. Recent years have seen a marked decline in the number of Leptospira positive aborted ovine and bovine foetuses in Northern Ireland, but data in the Republic of Ireland is incomplete due to the difficulties in diagnosing the infection. The aim of the present study was to investigate the prevalence of leptospirosis as a cause of abortion in cattle and sheep in the Republic of Ireland using a real time PCR technique and MAT. Results Pooled tissue samples (liver, kidney, lung, placenta) from 245 ovine foetuses (195 abortion events) tested by PCR, and MAT ( n = 104) during one lambing season in 2020 were negative for leptospirosis. Leptospira spp. was detected in two out of 437 bovine foetuses, collected at 412 abortion events during the calving season 2019/2020, by PCR. Using SecY single locus sequence typing both isolates were identified as L interrogans . None of the bovine foetuses ( n = 208) were positive by MAT. Abortion occurred during the winter, at around 6 months gestation in both cases. Gross and microscopic findings in the aborted foetuses were non-specific. Conclusion Leptospirosis contributes only marginally to abortions in sheep and cattle in Ireland. The PCR worked well on pooled foetal tissues, which should include at least liver, lung and placenta.