Replication of parental and F protein cleavage site mutant APMV-4 viruses in 2-week-old chickens.

aGroups of 2-week-old chickens were inoculated with each virus by the intranasal route. Three birds from each group were sacrificed, and tissues samples (brain, trachea, lung, and spleen) were collected and homogenized. To investigate virus replication, aliquots (100 µl each) of the collected samples on 4 dpi was inoculated into three eggs, and allantoic fluids were collected on 3 dpi. Virus replication was determined by hemagglutination assay.