A retrospective investigation into the outbreaks of abortions and orchitis in livestock in Namibia

Abstract This study investigated outbreaks of seemingly related abortions and orchitis which occurred in Namibia from 2016 to 2018. A combination of epidemiological studies (using questionnaires), necropsies, microbiology, serology, molecular biological techniques like PCR and mineral analytical techniques were used in an attempt to establish the aetiology of these abortion and orchitis outbreaks. The results showed that the outbreaks were limited to Namibia's east and central regions and mainly occurred on farms that reared cattle, sheep and goats and on farms with a mixture of these species. In some cases, horses and game species were also affected. Gross pathological findings included testicular enlargement, with focal haemorrhages and soft to hard testicular consistency in males. Histopathological findings included severe chronic orchitis, testicular degeneration, prominent interstitial mononuclear inflammatory cell infiltration with a few multinucleated inflammatory cells. In samples obtained from aborted fetuses, significant histopathological findings included meconium aspiration, funisitis, placentitis and cardiomyopathy in fetal tissues, whereas endometritis was the primary pathology observed in females. Brucella spp., Enterococcus spp., Escherichia coli, Streptococcus spp., Truperella pyogenes, micronutrient imbalances toxic and pathogenic abiotic nanoparticles which resulted from drought conditions that preceded these outbreaks, were identified as possible causes.