We further determined the ability of the APMV serotypes to replicate in chicken brains by inoculating 1-day-old chicks via the intracerebral route. The infected chickens were sacrificed daily and brain tissue was collected for virus titration (Fig. 4) . In chicks infected with neurovirulent APMV-1 strain BC, the virus reached the highest titer (.6.0 log 10 TCID 50 /g) in the brain at 2 dpi, resulting in the death of all of the infected chicks on 3 dpi. The non-neurovirulent LaSota strain was detected at low titer on day 1, but was not detected on subsequent days and did not cause disease or death during the 5 days of observation. APMV-3 strain reached a titer of 5 log 10 TCID 50 /g on 3 dpi, but did not cause disease or death of any of the infected chicks during the 5 days of observation. We detected a low level of replication of APMV-8 (,2 log 10 TCID 50 /g), with no observed disease or death. Replication of the other APMVs was not detectable on any day, and there was no detectable disease or death. Thus, APMV-3 was identified as the only neurotropic virus among APMV serotypes 2-9. However, despite the ability of APMV-3 to replicate to moderate titer in the brain, it did not cause discernable disease or death and thus was non-neurovirulent.