We further evaluated the multicycle replication of the APMVs in DF1 cells (Fig. 2 ). There was a great difference in the kinetics and magnitude of replication among different APMVs. APMV-1 strain BC and APMV-1 lentogenic strain LaSota grew better than any other APMVs and reached the highest titers (10 8 TCID 50 /ml) at 32 and 60 hpi, respectively. APMV-3 replicated relatively well, reaching 10 7 TCID 50 /ml at 72 hpi. The highest titers of APMV-2 and -5 also were detected at 72 hpi, but their titers were 4.0 log 10 lower than those of APMV-1. In general, replication of other APMV viruses was limited in DF1 cells (,10 2 TCID 50 /ml). Inefficient virus replication in vitro (i.e., APMV-4, 6, 7, 8, and -9) was correlated with the pattern of a single-cell infection as observed with CPE in infected cells (Fig. 1 ).