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Summary: A bull aged 16 months with bilateral testicular hypoplasia and azoospermia was persistently infected with bovine viral diarrhoea virus (BVDV). Viral antigen was detected in serum and semen by ELISA, but the animal was serologically negative. After slaughter, the genital tract was examined histopathologically and by immunohistochemistry, including double immunolabelling with BVDV antibody and either S-100 antibody (for Sertoli cells) or ferritin antibody (for Leydig cells). The seminiferous tubules of both testes were lined by a single layer of Sertoli cells and the germinal epithelium was completely absent except for a few remaining spermatogonia. BVDV antigen was demonstrated (1) in the media of arterial vessel walls of the testis, epididymis, urethra, prostate, and vesicular and bulbourethral glands, (2) in epithelial cells of the ductus epididymidis, the accessory glands and the urethra, and (3) in the testis, mainly in Sertoli cells and to a lesser extent in the spermatogonia that remained, but not in Leydig cells. The testicular hypoplasia was possibly linked to the BVDV infection. [Copyright &y& Elsevier]

Abstract: Switzerland is officially free from bovine Tritrichomonas foetus. While bulls used for artificial insemination (AI) are routinely examined for this pathogen, bulls engaged in natural mating, as well as aborted fetuses, are only very sporadically investigated, indicating that the disease awareness for bovine tritrichomoniasis is low. Natural mating in cattle is becoming increasingly popular in Switzerland. Accordingly, a re-introduction/re-occurrence of T. foetus in cattle seems possible either via resurgence from a yet unknown bovine reservoir, or via importation of infected cattle. The low disease awareness for bovine tritrichomoniasis might favor an unnoticed re-establishment of T. foetus in the Swiss cattle population. The aim of our study was thus to search for the parasite, and if found, to assess the prevalence of bovine T. foetus in Switzerland. We included (1) bulls over two years of age used in natural mating and sent to slaughter, (2) bulls used for natural service in herds with or without fertility problems and (3) aborted fetuses. Furthermore, the routinely examined bulls used for AI (4) were included in this study. In total, 1362 preputial samples from bulls and 60 abomasal fluid samples of aborted fetuses were analyzed for the presence of T. foetus by both in vitro cultivation and molecular analyses. The parasite could not be detected in any of the samples, indicating that the maximal prevalence possibly missed was about 0.3% (95% confidence). Interestingly, in preputial samples of three bulls of category 1, apathogenic Tetratrichomonas sp. was identified, documenting a proof-of-principle for the methodology used in this study. [Copyright &y& Elsevier]