Tritrichomonas foetus: prevalence study in naturally mating bulls in Switzerland.

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.

[Vaccination against bluetongue: safety and immune response in the field]. / Impfung gegen die Blauzungenkrankheit: Verträglichkeit und Immunantwort in der Praxis.

Bluetongue, caused by the bluetongue virus serotype 8 has rapidly spread through Europe since 2006. The first cases in Switzerland were detected in October 2007. The European Union and Switzerland launched a vaccination campaign in June 2008. This study aims to demonstrate the safety and the immune response of the three vaccines used in Switzerland under practical conditions in the field. The trial was carried out in cattle, sheep and goats. Based on the results of this study recommendations for the 2009 campaign are presented.

Testicular hypoplasia in a bull persistently infected with bovine diarrhoea virus.

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.

[Search for Neospora caninum DNA in bull semen using PCR ]. / Untersuchung von bovinem Sperma auf Neospora caninum-DNA mittels PCR.

Neospora caninum represents one of the most frequent abortifaciant organisms worldwide. The parasite is diaplacentally transmitted from the pregnant cow to the fetus, where it normally leads to the delivery of a healthy, however persistently infected calf. Abortion thus is a relative rare event. The transmission of bovine neosporosis occurs in more than 90% of the cases vertically due to the endogenous reactivation of a persistently infected mother. Exogenous infections are therefore responsible for less than 10% of the cases. The question arises about which infection sources may be relevant in this context. In Switzerland, the role of dogs as definitive hosts has been shown to be of low significance in that respect. Recently, discussion focused on the potential of infectious bull semen following natural or artificial insemination. Thus, a few years ago a report documented the detectability of N. caninum-DNA in the semen of naturally infected bulls by nested-PCR. As a consequence, we decided to gain own experience by investigating 5 separate semen specimens per animal, originating from 20 N. caninum-seropositive bulls used for artificial insemination in Switzerland. All probes turned out to be negative by nested PCR. Based upon our laboratory experiences, the potential bull semen-associated Neospora-problem seems not to affect the Swiss bull population, thus there is no evidence to include further respective means of control.

[Lead poisoning in calves due to old white lead paint]. / Vergiftung bei Mastkälbern mit Bleiweiss.

A case of poisoning by chronic ingestion of lead in calves with a peracute clinical course is described. The source of lead was a prime coat of white lead on old white painted doors. These doors originated from an institution for aged people and had been used as pen walls for fattening calves. About 12 weeks later five animals died within hours after onset of CNS-symptoms. The post mortem examination of three animals revealed one with multifocal laminar edema and mild vasculitis in the cerebrocortex, one with acid fast intranuclear inclusion bodies in the renal tubular epithelial cells and one without lesions. Liver, kidney and abomasal contents of two animals were analysed for lead content. The concentration was diagnostic for lead poisoning in one case only.