Testicular pathology, gonadal and epididymal sperm reserves of Yankasa rams infected with experimental Trypanosoma brucei brucei and Trypanosoma evansi

Abstract

Aim:The study was conducted to evaluate the pathological effects of trypanosomosis on the testes, gonadal, and epididymal sperm reserves of Yankasa rams for 98 days.Materials and Methods:A total of 16 Yankasa rams, aged between 24 and 30 months and weighed between 22 and 25 kg, were acclimatized for a period of 2-months in a clean fly proof house and were adequately fed and given water ad-libitum. Of the 16 rams, 12 that were clinically fit for the experiment at the end of the acclimatization period were randomly divided into four groups: Groups I, II, III, and IV, each having 3 rams. Groups I and II were each challenged singly with experimental Trypanosoma brucei brucei (Federer strain) and Trypanosoma evansi (Sokoto strain), respectively, while Group III was challenged with mixed T. brucei brucei and T. evansi parasites (50% of each species in the infective inoculum) and Group IV was left as an uninfected control. Each infected ram received 2 mL of the infected blood containing 2×106 trypomastigotes via the jugular vein, while the control group received 2 mL each, normal saline.Results:All the infected rams developed clinical signs typical of trypanosomosis at varying pre-patent periods. The gross lesions observed in the infected rams in Group II were moderate and more severe in those of Groups I and III. Histological sections of the testes of infected rams (Groups I, II, and III) showed moderate (T. evansi-infected group) to severe (mixed and T. brucei brucei-infected groups) testicular degenerations with reduction in number of spermatogenic cell layers, degenerated seminiferous tubules, congested interlobular spaces, loss of tissue architecture with significant (p<0.01) depletion, and loss of gonadal and epididymal sperm reserves in Groups I and III in comparison to Group II and the control Group IV. No observable clinical signs and histopathological lesions were found in those rams of the control Group IV.Conclusion:The study concluded that trypanosomosis due to experimental T. brucei brucei or T. evansi or mixed infections (of both parasites) caused testicular damage, decreased epididymal and gonadal sperm reserves and an important cause of infertility in Yankasa rams.

Changes of reproductive indices of the testis due to Trypanosoma evansi infection in dromedary bulls (Camelus dromedarius): Semen picture, hormonal profile, histopathology, oxidative parameters, and hematobiochemical profile

“…In contrast, the rate of dead sperm increased, accompanied by increased abnormalities in morphology. These results were the same as those reported in Yankasa rams infected with T. evansi experimentally [ 5 , 36 ].…”

“…The histopathology of the testis from infected camels in the current study showed degenerative changes of the seminiferous tubules characterized by vacuolation with scarce sperm cells and spermatids. The same results were detected in the experiment of rams infected with T. brucei and T. evansi [ 36 ]. Furthermore, another study was carried out in a deer infected with the same parasite, which revealed that the seminiferous tubule has degeneration accompanied by degeneration of sperm in the ducts of the epididymis [ 39 ].…”

Time-Dependent Testicular and Epididymal Damage in Rabbit Bucks Experimentally Infected with Trypanosoma Brucei Brucei

“…Also, most of the epididymal sperm reserves were empty but contained proteinaceous fluid. Atrophy of the seminiferous tubules has been reported in T. evansi infected camels (20) and sheep infected with T. brucei (19), and T. vivax (35). Atrophy is the result of progressive testicular degeneration (36), which is caused by intermittent fluctuations in temperature and invasion of the testis by the parasite.…”

“…T. brucei brucei causes a varying degree of disease associated with the reproductive system among domestic animals. In males, it is characterized by poor quality semen, decreased testosterone level, penile protrusion, preputial inflammation, scrotal dermatitis, loss of libido, increased reaction time, sperm abnormalities, orchitis and severe testicular degeneration (5,16,17,18,19,20). In females, it is manifested by abortion, stillbirths, posterior paresis as well as reproductive and endocrine lesions (21,22,23,24).…”

Rare report of orchitis in a bull due to Trypanosoma evansi infection

“…During the pathogenesis, degenerative changes in the testes, delayed puberty further leads to loss of libido was reported in trypanosomosis. According to Wada et al (2016) direct trypanosomal damage and pathological changes in the testis are responsible for the aspermia in Trypanosoma evansi infected male goats. During the T. vivax infection it causes testicular and epididymal lesions and leads to development of the infertility and sterility in animals chronically affected with T. vivax (Sekoni et al 2004).…”