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.
The 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.