Antigenic differences between strains of foot-and-mouth disease virus of type SAT 1

Abstract

Antigenic differences between the strains RV 11 and SA 13/61 of foot-and-mouth disease virus (type SAT 1) were studiedin vivoby cross-protection tests. Cattle inoculated with formolized antigen of either strain developed good immunity to experimental infection with the identical strain but little resistance to the other strain.In vitrothe results of complement fixation tests and of serum-virus neutralization tests in tissue culture were consistent with the observations madein vivo. The results of studies on the serological relationships between four strains of type SAT 1 are presented.The importance of strain differences in the epizootiology and control of the disease is discussed briefly.The authors wish to thank Dr I. A. Galloway and Dr J. B. Brooksby for their advice and criticism, and to acknowledge the valuable technical assistance of Mr K. Herniman, Mr R. L. G. King and Mr E. Scoates.