Edited by Tamas Dalmay Keywords:Highly pathogenic H5N1 avian influenza Chicken Duck MicroRNA Immune organ a b s t r a c tChickens are susceptible to the highly pathogenic H5N1 strain of avian influenza virus (HPAIV), whereas ducks are not. Here, we used high-throughput sequencing to analyse the microRNA expression in the spleen, thymus and bursa of Fabricius of H5N1-HPAIV-infected and non-infected chickens and ducks. We annotated the genomic positions of duck microRNAs and we compared the microRNA repertoires of chickens and ducks. Our results showed that the microRNA expression patterns in the homologous immune organs of specific-pathogen-free (SPF) chickens and ducks diverge substantially. Moreover, there was larger divergence between the microRNA expression patterns in immune organs of HPAIV-infected chickens than HPAIV-infected ducks. Together, our results might help to elucidate the roles of microRNAs in the divergent immunity of chickens and ducks against H5N1 HPAIV.

The aim of this study was to establish a multiplex PCR (mPCR) method that can simultaneously detect canine parvovirus (CPV-2), canine coronavirus (CCoV) and canine adenovirus (CAV), thereby eliminating the need to detect these pathogens individually. Based on conserved regions in the genomes of these three viruses, the VP2 gene of CPV-2, the endoribonuclease nsp15 gene of CCoV, and the 52K gene of CAV were selected for primer design. The specificity of the mPCR results showed no amplification of canine distemper virus (CDV), canine parainfluenza virus (CPIV), or pseudorabies virus (PRV), indicating that the method had good specificity. A sensitivity test showed that the detection limit of the mPCR method was 1 × 10 viral copies. A total of 63 rectal swabs from dogs with diarrheal symptoms were evaluated using mPCR and routine PCR. The ratio of positive samples to total samples for CPV-2, CCoV, and CAV was 55.6% (35/63) for mPCR and 55.6% (35/63) for routine PCR. Thirty-five positive samples were detected by both methods, for a coincidence ratio of 100%. This mPCR method can simultaneously detect CCoV (CCoV-II), CAV (CAV-1, CAV-2) and CPV-2 (CPV-2a, CPV-2b, CPV-2c), which are associated with viral enteritis, thereby providing an efficient, inexpensive, specific, and accurate new tool for clinical diagnosis and laboratory epidemiological investigations.

The enzootic and zoonotic nature of H9N2 avian influenza viruses pose a persistent threat to global poultry industry and human health. This particular subtype influenza virus raises public concerns because it possesses human receptor specificity. In this study, four H9N2 virus strains clustered into the G57-like viruses preferentially bound to SAα2,6 receptors as demonstrated in the results from the receptor-binding assay. The molecular dynamic simulation showed that HAQ226L substitution of H9N2 viruses may alter the conformation of the 220-loop of hemagglutinin (HA) and thus optimize the contacts between HA and human receptors, thereby increasing the preference for α2,6-linkages. The acquisition of an additional N-glycosylation site at position 264 close to the enzyme active sites of neuraminidase of H9N2 viruses induced the loss of hydrogen bonding between 276E at the enzyme active sites and Zanamivir and further led to occurrence of Zanamivir-resistant of viruses. This study shows the relationship between the conformational changes due to amino acid variations and viral biological phenotypes, which emphasizes the necessity for monitoring the continual evolution of H9N2 viruses and comprehensively assessing their potential zoonotic threat.