The H10 subtype avian influenza viruses (H10N4, H10N5 and H10N7) have been reported to cause disease in mammals, and the first human case of H10N8 subtype avian influenza virus was reported in 2013. Recently, H10 subtype avian influenza viruses (AIVs) have been followed more closely, but routine diagnostic tests are tedious, less sensitive and time consuming, rapid molecular detection assays for H10 AIVs are not available. Based on conserved sequences within the HA gene of the H10 subtype AIVs, specific primer sets of H10 subtype of AIVs were designed and assay reaction conditions were optimized. A reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay was established for the rapid detection of H10 subtype AIVs. The specificity was validated using multiple subtypes of AIVs and other avian respiratory pathogens, and the limit of detection (LOD) was tested using concentration gradient of in vitro-transcribed RNA. The established assay was performed in a water bath at 63 °C for 40 min, and the amplification result was visualized directly as well as under daylight reflections. The H10-RT-LAMP assay can specifically amplify H10 subtype AIVs and has no cross-reactivity with other subtypes AIVs or avian pathogens. The LOD of the H10-RT-LAMP assay was 10 copies per μL of in vitro-transcribed RNA. The RT-LAMP method reported here is demonstrated to be a potentially valuable means for the detection of H10 subtype AIV and rapid clinical diagnosis, being fast, simple, and low in cost. Consequently, it will be a very useful screening assay for the surveillance of H10 subtype AIVs in underequipped laboratories as well as in field conditions.

Avian reovirus (ARV) is an important pathogen of poultry and causes significant economic losses to the poultry industry. To develop a rapid and sensitive method for the surveillance of ARV, a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was established using a set of six primers specific to the S1 gene segment of ARV. The established assay was performed at 62^oC for 60 min in a thermal block, and the result was visualized directly under daylight or ultraviolet light. The detection limit of the RT-LAMP assay was 10 fg total RNA, which was 100-fold higher than that of reverse transcriptase polymerase chain reactions. The specificity of the assay was supported by the lack of cross-reaction with other avian pathogens. Furthermore, viral RNAs of field isolates were successfully detected by the assay. Overall, the newly established RT-LAMP assay is simple, rapid, sensitive, specific, and can visually detect ARV without the use of any specialized equipment.

The entire mitochondrial genome of Jingxi duck from China was 16,603 bp in length, and has been analyzed for gene locations, length, start codons and stop codons. With the base composition of 29.20% for A, 22.19% for T, 32.82% for C, 15.79% for G, so the percentage of A and T (51.39%) was slightly higher than those of G and C. The Jingxi duck mitochondrial genome contained two ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes and one non-coding control region (D-loop region). The arrangement of these genes was the same as most birds. The complete mitochondrial genome sequence of the Jingxi duck will be useful for phylogenetics, and provide an important data set for further study on the germplasm resources.

The complete mitochondrial genome sequence of the Longsheng duck was measured by PCR-based methods. Our research findings revealed that the entire mitochondrial genome of the Longsheng duck was 16,603 bp (GenBank accession number: KJ739616). The contents of A, T, C, and G in the mitochondrial genome were 29.22%, 22.21%, 32.79% and 15.77%, respectively, which were similar to the majority of most avian species. The complete mitochondrial genome of the Longsheng duck contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and one control region. Components of the Longsheng duck’s mitochondrial genome were similar to those of other Anas platyrhynchos in gene arrangement and composition. The complete mitochondrial genome of the Longsheng duck should provide essential information for understanding phylogenetic relationships of duck mitochondrial genome.

H9N2 avian influenza virus (AIV) is widely prevalent in poultry in China. To understand the genetic characteristics and evolution of H9N2 AIVs in Guangxi, southern China, the complete genomes of H9N2 AIVs from 1999–2023 were systematically analysed. Maximum likelihood (ML) trees indicated that H9N2 AIV gene sublineage diversity contributed to genotype diversity, yielding 17 genotypes (G1–G17). Since 2010, genotype G14 (also known as genotype S or G57) has become predominant in poultry in Guangxi. Phylogenetic analysis in the HA has resulted in the distancing of recent Guangxi isolates from the vaccine strains. This study also revealed that the genotypes of H9N2 AIVs infecting swine, equines and canines in Guangxi were consistent with those found in avian species at the same time, highlighting the capacity of H9N2 AIVs to be transmitted across species. The antigenic residues in the HA head region and NA protein of the Guangxi isolates from 2020–2023 changed significantly compared to the vaccine strains, suggesting possible antigenic drift in these viruses. Amino acid analysis of the HA protein revealed that 84.9% (73/86) of H9N2 AIV isolates from Guangxi, including those from live poultry markets, preferentially bound to α-2,6 sialic acid receptors. Considerable attention should be given to cross-species transmission of H9N2 AIV in the region. On the basis of these findings, strengthening the monitoring of H9N2 AIV in poultry in Guangxi is essential.