Table 3.

Infectivity results obtained with different Asian FMDV strains in comparison with O/TAW/97

^*Viral concentration of inoculums expressed as plaque forming units per mL (PFU/mL) obtained in BHK cells. ^†Determination of 50% pig heel infectious doses (PHID₅₀/mL) in inoculums after intradermal inoculation in the heel bulb. ^‡PFU of virus calculated to be one PHID₅₀. ^§Each pig received values of 10⁵ PFU of virus, projected by multiplying the value of PFU/mL by 11.11 µL the estimated volume of inoculums (5 µL × 2 of first dilution plus three more dilutions of a volume of 1/10 of the immediate previous dilution). ^∥Determination of PHID₅₀ that each animal received, based on volume estimated above. ^¶Relative infectivity of each virus compared with porcine infectivity of O/TAW/97. This number indicates how many more viral particles than O/TAW/97 are needed to obtain 1 PHID₅₀.