The infectivity assay of foot-and-mouth disease virus in pigs

Abstract

FMDV strains were titrated in pigs by inoculation of the bulb of the heel of the foot, the coronary band region of the foot, and the tongue. Heel inoculation gave end-points approximately 300-fold higher than did the other two methods. Parallel titrations in cattle and mice gave infectivity estimates approximately 10-fold and 100-fold higher, respectively, than did heel titration of pigs. The average variance of individual end-points determined for heel titration was 0·46 (log 10 units) and that determined for coronary-band titration was 0·74. The sources of variations in end-points given by heel titrations are discussed.