Howell, P.G.Jansen, B.C.2016-07-132016-07-1320161963Howell, PG 1963,'Observations on the occurrence of African horsesickness amongst immunised horses', Onderstepoort Journal of Veterinary Science and Animal Industry, vol. 30, no. 1, pp. 3-10.0330-2465http://hdl.handle.net/2263/55758The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentation PDF-Format.During the course of an epizootic of African horsesickness it was possible to establish that:- (1) strains of virus apparently homologous with components of the polyvalent vaccine could be reisolated from clinically affected equines previously immunised; (2) infection by a specific immunological type of virus could be correlated with an absence of homologous antibody in the reacting animal; (3) animals failed to develop specific antibodies to certain components of the polyvalent vaccine in spite of repeated immunisation.en©1939 ARC-Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). ©2016 University of Pretoria. Department of Library Services (digital).Veterinary medicineVeterinary medicine -- South AfricaArticle