Institute of Animal Pathology, University of Bern, Länggassstrasse 122, 3012, Bern, Switzerland.
IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain.
Parasitol Res. 2020 Jul;119(7):2257-2262. doi: 10.1007/s00436-020-06695-3. Epub 2020 May 26.
Bulls chronically affected by bovine besnoitiosis can suffer from sterility. There is limited information about the distribution of Besnoitia cysts and their associated lesions within the male genital organs. This work describes the gross and histological abnormalities in the genital organs of 6 bulls chronically infected with Besnoitia besnoiti, including both clinically (n = 4) and subclinically (n = 2) affected cases. Parasitic cysts were observed in the genital organs of all the clinically affected bulls. The tissue cysts were most commonly found within the pampiniform plexus (4/4), where they were often seen within venous vascular walls and associated with vasculitis, followed by epididymis (3/4), tunica albuginea (2/4), and penis (1/4). In decreasing order of their frequency, observed abnormalities included seminiferous tubule degeneration, testicular fibrosis, testicular necrosis, lack of/or diminished numbers of spermatozoa, testicular atrophy, and Leydig cell hyperplasia. Only one of the subclinically infected bulls had few Besnoitia cysts within the pampinoform plexus, which was associated to small areas of necrosis and mineralization in the ipsilateral testicle. Results indicate that Besnoitia cysts and genital abnormalities are frequent in bulls chronically affected by bovine besnoitiosis, while they are mild and scarce in subclinically affected ones. Moreover, present data show that Besnotia-associated testicular lesions can occur without the presence of cysts within the testicular parenchyma. B. besnoiti cysts seem to have a tropism for the vascular structures of the spermatic chord, which may cause testicular abnormalities via vascular damage, reduced blood flow, and/or impaired thermoregulation and subsequently lead to the observed testicular lesions.
慢性感染贝氏贝诺孢子虫的公牛可能会不育。关于雄性生殖器官内贝氏贝诺孢子虫包囊及其相关病变的分布，相关信息有限。本研究描述了 6 头慢性感染贝氏贝诺孢子虫的公牛的生殖器官的大体和组织学异常，包括临床（n=4）和亚临床（n=2）受感染的病例。在所有临床受感染的公牛的生殖器官中都观察到了寄生虫包囊。组织包囊最常见于精索丛（4/4），常位于静脉血管壁内，并与血管炎相关，其次是附睾（3/4）、白膜（2/4）和阴茎（1/4）。按其出现频率降序排列，观察到的异常包括生精小管退化、睾丸纤维化、睾丸坏死、精子缺乏/减少、睾丸萎缩和间质细胞增生。只有 1 头亚临床感染的公牛在精索丛内有少量的贝氏贝诺孢子虫，与之相关的是同侧睾丸的小面积坏死和矿化。结果表明，在慢性感染牛贝氏贝诺孢子虫的公牛中，贝氏贝诺孢子虫包囊和生殖器官异常很常见，而在亚临床感染的公牛中则较为轻微和罕见。此外，目前的数据表明，Besnotia 相关的睾丸病变可能在睾丸实质内没有包囊的情况下发生。B. besnoiti 包囊似乎对精索的血管结构具有亲嗜性，这可能通过血管损伤、血流减少和/或热调节受损导致睾丸异常，从而导致观察到的睾丸病变。
