Bovine besnoitiosis : transfer of colostral antibodies with observations possibly relating to natural transmission of the infection

Colostral antibodies to B. besnoiti were detected by immunofluorescence in four calves born to two Besnoitia-infected dams, with titres ranging from 1:64 to 1:1024. A specific antibody titre of 1:1024 was found in colostrum collected from one of the dams. Two of the newborn calves, when sampled immediately after birth, were serologically negative to B. besnoiti, but became positive on the next day. In all the calves, antibodies were detectable up to the age of 4 months. Observations concerning passive transfer of antibodies from Besnoitia-infected dams to offspring, and transmission of the infection among infected and non-infected closely kept cows, are discussed.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Approaches to vaccination against Theileria parva and Theileria annulata

Despite having different cell tropism, the pathogenesis and immunobiology of the diseases caused by Theileria parva and Theileria annulata are remarkably similar. Live vaccines have been available for both parasites for over 40 years, but although they provide strong protection, practical disadvantages have limited their widespread application. Efforts to develop alternative vaccines using defined parasite antigens have focused on the sporozoite and intracellular schizont stages of the parasites. Experimental vaccination studies using viral vectors expressing T. parva schizont antigens and T. parva and T. annulata sporozoite antigens incorporated in adjuvant have, in each case, demonstrated protection against parasite challenge in a proportion of vaccinated animals. Current work is investigating alternative antigen delivery systems in an attempt to improve the levels of protection. The genome architecture and protein-coding capacity of T. parva and T. annulata are remarkably similar. The major sporozoite surface antigen in both species and most of the schizont antigens are encoded by orthologous genes. The former have been shown to induce species cross-reactive neutralizing antibodies, and comparison of the schizont antigen orthologues has demonstrated that some of them display high levels of sequence conservation. Hence, advances in development of subunit vaccines against one parasite species are likely to be readily applicable to the other

Basic pronciples of Theileria annulata control

Meeting: Workshop on Theileriosis, 7-9 Dec. 1976, Nairobi, KEIn IDL-134