Tissue (re)distribution of Trypanosoma equiperdum in venereal infected and blood transfused horses

This study describes the distribution of the parasite after infection by artificial insemination (AI) or blood transfusion. Mares (N = 4) were artificially inseminated with T. equiperdum spiked semen whereas stallions (N = 4) were infected by blood transfusion. The course of the disease was monitored by parasitological (Woo) and molecular (PCR) tests and clinical signs and haematological parameters were recorded. At 120 days post infection, horses had a full necropsy, histopathology and PCR. A similar pattern of parasitaemia, disease progression and tissue distribution were seen in all horses. Ejaculated semen in the preclinical stage and epididymal semen in the chronic stage of the disease was positive on PCR and caused infection in mice. Cymelarsan® treatment in the chronic stage did not result in a clinico-haematological or histopathological improvement. At necropsy, lesions were observed in the nervous and reproductive system. Histopathological lesions were most severe in the peripheral nerves and associated ganglia, the testicles and genital mucosae with multifocal infiltration of lymphocytes, plasma cells and histocytes. The parasites disseminated to several tissues including the nervous system, testicles and semen. The results indicate that transmission of T. equiperdum is possible through semen even from symptomless stallions post-treatment.Graphic Abstract
Source: Veterinary Parasitology - Category: Veterinary Research Source Type: research