An inactivated bivalent oil foot and mouth disease (FMD) vaccine was prepared using
the local isolated types of the caused virus (FMDV type O/Egypt/93 and A/1/Egypt/2006).
This vaccine was subjected to the quality control tests which revealed that it is free from
foreign contaminants, safe and potent for Guinea pigs which were used as a model animal for
determination of the vaccine PD50. The obtained results showed that vaccinated Guinea pigs
exhibited good levels of homologous FMD antibodies; as shown by serum neutralization test
and ELISA; by the 3rd week post vaccination enabling them to withstand the challenge
viruses with protection ratios of 100%; 75% against type O for undiluted and 1/4 diluted
vaccine respectively while 100% protection was detected against type A with the 2 vaccine
dilutions. Higher vaccine dilutions were found to be non-protective showing low protection
ratios (25-0%) It was found that Guinea pig 50% protective dose (GPPD50) was 7.94 for
FMD virus type O and 11.06 for type A. Such permissible values of vaccine potency and
PD50 confirm the possibility of the use of Guinea pigs to determine the PD50 of FMD vaccine
as a model animal instead of cattle saving effort and cost.