Location: Animal Parasitic Diseases LaboratoryTitle: Development of early tissue cysts and associated pathology of Besnoitia Besnoiti in a naturally infected bull (Bos Taurus) from South Africa) Author
Submitted to: Journal of Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/13/2013
Publication Date: 6/1/2013
Citation: Dubey, J.P., Wilpe, V., Blignaut, D., Williams, J. 2013. Development of early tissue cysts and associated pathology of Besnoitia Besnoiti in a naturally infected bull (Bos Taurus) from South Africa. Journal of Parasitology. 99:459-466. Interpretive Summary: Besnoitia and Toxoplasma are related single-celled parasites that cause clinical disease in livestock. Differential diagnosis of these infections is sometimes difficult because these parasites have shared proteins (antigens) that are used for serological (blood) tests. For example Toxoplasma immune serum reacts with Besnoitia parasites in sections of infected tissues. Besnoitia besnoiti affects cattle and the disease is now spreading from Africa to Europe, but does not occur in USA. In the present study, the authors describe unusual features of pathology and of the associated organisms IN CASE FROM South Africa.The results can aid in correct diagnosis. The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: Besnoiti besnoiti is an apicomplexan that causes serious economic loss in cattle in many countries and the disease is now spreading in Europe. Two phases of bovine besnoitiosis are recognized clinically. An acute febrile phase characterized by anasarca and necrosis of skin is associated with multiplication of tachyzoites in vascular endothelium; this phase is short lived and rarely diagnosed. Chronic besnoitiosis characterized by dermal lesions is associated with the presence of macroscopic tissue cysts and is diagnosed easily. Here, the development of early B. besnoiti tissue cysts in a naturally infected Hugenot bull from South Africa is described for the first time. Tissue cysts were 10-70 µm in diameter, contained 1-12 bradyzoites, and were most numerous in the dermis, testicles, and pampiniform venous plexus. Amylopectin granules in bradyzoites stained red with periodic acid Schiff (PAS) reaction. Bradyzoites varied in size and in the intensity of PAS reaction (some were PAS-negative), some were plump, and others were slender. With immunohistochemical staining with Besnoitia oryctofelisi, and bradyzoite-specific antibodies (BAG1) the staining was confined to parasites and all intracystic organisms were BAG-positive. With Gomori’s silver stain, only bradyzoites were stained very faintly, whereas the rest of the cyst was unstained. Ultrastructurally, many tissue cysts contained dead bradyzoites and some appeared empty. Unlike bradyzoites from mature cysts, bradyzoites in the present case contained few or no micronemes. These findings are of diagnostic significance. Ultrastructually, host cyst cells had features of myofibroblasts and immunohistochemistry using antibodies against MAC387, lysozyme, vimentin, Von Willebrands factor, and smooth muscle actin confirmed this. Associated clinical findings, lesions and histopathology are briefly presented. The bull died of nephrotic syndrome; anasarca in acute besnoitiosis due to protein-losing glomerulopathy is a finding not previously reported in cattle.