DIFFERENTIATION OF WILD-TYPE AND VACCINE-TYPE CANINE PARVOVIRUSES BY PCR AND RESTRICTION-ENZYME ANALYSIS

The polymerase-chain re action (PCR) and restriction-fragment-length-p olymorphism (RFLP) analysis were used to differentiate the wild- and v accine-type of canine parvovirus (CPV) in Japan. The entire coding reg ion of the CPV genome was enzymatically amplified, and the PCR product s of three wild strains and four vaccine strains were analysed using R FLP assay. Then, two polymorphic regions in the VP1/VP2 gene were sele cted to generate strain-specific RFLP patterns. By using four restrict ion enzymes, wild and vaccine strains were clearly differentiated; onl y two vaccine strains, probably of the same origin, were indistinguish able from each other. The wild strains retained strain-specific RFLP p atterns throughout in vitro passage, and there was no diversity of RFL P patterns among the different lots of vaccine strains. A total of 21 recent field samples were tested, showing RFLP patterns identical to t hose of a wild strain isolated in 1991. These results suggest that the PCR-RFLP analysis is a practical and reliable method of differentiati ng wild- and vaccine-type CPVs.