STUDY ON ANTIGENIC VARIATION OF FOOT AND MOUTH DISEASE ISOLATES SECURED. DURING THE LAST OUTBREAKS

Abstract

Three FMD viral isolates or strains had been isolated from different outbreaks at three governorates (Sharquia, Suez and Agga locality), during 1972, 1987 and 1993 years from cattle species. The isolates were typed by complement fixation test against the seven serotypes and the results revealed that all strains were of the type "0" FMD virus.

2. The isolate strains studied became adapted after the 3 g and 4 :th passage in BK cell cultures, they yielded infective titre ranged between (4 and 5.5 log.,0 TCI050) and complement fixing antigenicity ranged between (1.37- 1.75 log.,0 CFU) I ml.

3. Hyperimmune sera against all the isolated strains were

prepared in Guinea pigs and titrated by fixation test showing a titre of 160 (2.2 against their homologous antigens.

complement log.,0 CFU}

4. The study of antigenic relationship and dominating state for the three isolates revealed that isolate (0.,/72 and 0.,/87) and (0.,/72 and 0.,/93) showing a little variation and be under class "subtype similar but still different and had a percentage between (32 - 70 %) while isolate strain (0.,/87 and 0.,/93) 1ie under the class "subtype similar" and had a percentage between (70- 100 %}.