Virological and immunological studies on foot and mouth disease virus type SAT2 naturally infected and vaccinated buffalo cows and their calves

Aim: Due to inadequate data on the dynamics of foot and mouth disease (FMD) infection in buffalo, the present work was aimed at investigating some virological and immunological aspects of FMD virus (FMDV) SAT2 infection in naturally exposed and vaccinated buffalo cows and their calves. Materials and Methods: The study employed clinical observation and examination, virus isolation in mice brain and cell culture, in addition to virus detection using complement fixation test; indirect sandwitch enzyme-linked immunosorbent assay and demonstration of RNA by reverse transcription polymerase chain reaction for confirmation the results. Results: FMD type SAT2 antibodies was detected in a protective level by the 1st week post infection and 3rd week post vaccination and peak titers were recorded by the 3rd week, 12th week in infected and vaccinated buffaloes, respectively. These titers began to decline to reach their lowest protective levels by the 36th week, 12nd week in infected and vaccinated buffaloes respectively. The SAT2 antibodies in calves born to vaccinated and infected buffalo cows were detected on the 1st day post parturation through the suckling of their Dam’s colostrums. The highest maternal antibody titers were recorded in sera by the 2nd day post parturation. These antibodies declined gradually to reach their lowest protective levels on14th week, 16th week post parturition in calves rom vaccinated and infected buffaloes, respectively. High antibody titers in the colostrums and milk of vaccinated and naturally infected buffalo cows were recorded at parturition, and they began to decrease gradually recording their lowest protective titers by 10th and 12nd week post parturition respectively. Conclusion: FMDV serotype SAT2 was confirmed as a causative agent of the suspected FMD signs in pregnant buffalo at El-Fayoum Governorate, Egypt, during 2012. Vaccinated and naturally infected buffalo cows were able to provide their calves with high levels of maternal derived antibodies through their colostrums, which could protect new born calves for not less than 14 week post parturation.