ABSTRACT
Newcastle disease virus (NDV, Avian orthoavulavirus type 1, AOAV-1) is a contagious high-impact poultry pathogen with infections detected worldwide. In the present study, 19,500 clinical samples from wild bird species and poultry collected from 28 regions of Russia between 2017 and 2021 were screened for the presence of the AOAV-1 genome. NDV RNA was detected in 15 samples from wild birds and 63 samples from poultry. All isolates were screened for a partial sequence of the fusion (F) gene that included the cleavage site. Phylogenetic analysis demonstrated that lentogenic AOAV-1 I.1.1, I.1.2.1, and II genotypes were dominant among vaccine-like viruses in the territory of the Russian Federation. A vaccine-like virus with a mutated cleavage site (112-RKQGR^L-117) was detected in turkeys. Among the virulent AOAV-1 strains, viruses of the XXI.1.1, VII.1.1, and VII.2 genotypes were identified. The cleavage site of viruses of the XXI.1.1 genotype had a 112-KRQKR^F-117 amino acid sequence. The cleavage site of viruses with VII.1.1 and VII.2 genotypes had a 112-RRQKR^F-117 amino acid sequence. The data collected by the present study demonstrate the distribution and dominance of the virulent VII.1.1 genotype in the Russian Federation between 2017 and 2021.
ABSTRACT
Chickens were intranasally inoculated with the swine influenza virus (SIV) A/swine/NC/307408/04 (H3N2) (NC/04 SIV) to determine the infectivity of a North American SIV for chickens, as well as the possibility of chicken meat serving as a transmission vehicle for SIV. White leghorn (WL) layer-type chickens were used for initial pathotyping and infectivity tests, and a more comprehensive intranasal pathogenesis study was done with white Plymouth rock (WPR) broiler-type chickens. None of the NC/04 SIV-inoculated WL or WPR chickens displayed clinical signs. Serologic tests showed that the virus was able to infect both intranasally inoculated WL and WPR chickens, but the antibody titers were low, suggesting inefficient replication. Some of the NC/04 SIV-inoculated WL chickens shed low levels of virus, mostly from the alimentary tract, but viral shedding was not detected in NC/04 SIV-inoculated WPR chickens. The comprehensive pathogenesis study demonstrated that the virus did not cause systemic infections in WPR chickens, and feeding breast and thigh meat from the NC/04 SIV-inoculated WPR to WL chickens did not transmit NC/04 SIV.
