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Goose circovirus (GoCV) is a recently identified pathogen in geese that is known to cause slow growth, feather disorder syndrome, and immunosuppression. Infection with GoCV may increase the risk of coinfections with multiple pathogens, leading to significant economic losses in the goose industry. However, due to a lack of serological detection methods, analysis of viral nucleic acids has been widely used in GoCV epidemiological surveys, which has limited accurate monitoring of the prevalence of GoCV. In this study, we developed and optimized an indirect ELISA method based on the prokaryotic-expressed recombinant GoCV capsid protein (△Cap-iELISA). The △Cap-iELISA was then used to test 349 goose serum samples collected from Guangdong, Shandong, and Fujian provinces during 2023 and 2024. The results showed that the positive rate of GoCV antibodies in the sampled geese was 71.06%. Further analysis indicated that the positive rate of GoCV antibodies increased with the age of the geese. In conclusion, we have developed a novel iELISA method that is well-suited for large-scale clinical detection and early diagnosis of GoCV infection. Notably, a significant correlation between age and the positive rate of GoCV antibodies among geese was observed based on this newly established method., Competing Interests: WZ was employed by WANMUZHOU Biotechnology Limited Company. HW was employed by Shenzhen Kingkey Smart Agriculture Times Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The handling editor CW declared a past co-authorship with the author RL., (Copyright © 2025 Chen, Xue, Yao, Wang, Zhu, Wang, Zhang, Tang, Liu and Chen.)

To understand the prevalence, coinfection with other viruses, underlying genetic evolution, recombination, and molecular biological characteristics of goose circovirus (GoCV) in Guangdong, China, from December 2019 to August 2020, 310 tissue samples of geese showing stunted growth and feather disorder syndrome were collected from this region and analyzed. GoCV, Tembusu virus, waterfowl paramyxovirus, avian influenza virus, fowl adenovirus type 4, and duck plague virus were detected with PCR or real-time PCR. Thirty-one complete GoCV viral genomes were obtained from 164 PCR-verified GoCV nucleotide-positive samples and subjected to phylogenetic analysis, gene recombination analysis, and genome secondary structure prediction. The results showed that more than half of the samples were GoCV positive, and 31.1% of the GoCV-positive samples were from coinfections with at least one of the other viruses. The phylogenetic analysis showed that the GoCVs could be divided into three genome types. The genes of most main epidemic strains now circulating in Guangdong belonged to the Ia subtype, and some strains gradually formed a new Ib subtype. The secondary structure of the viral genome was similar to that of other known circoviruses. Furthermore, B cell linear epitope prediction and protein structure homology modeling of the viral capsid protein were performed based on the viral amino acid sequences. The results showed that the spatial structure of the capsid protein of the 31 sequenced strains was similar to that of duck circovirus and consisted of two β-sandwich conformations. A total of five B cell linear epitopes were predicted, and four of them were mapped on the predicted model of the capsid protein of GoCVs. This report provides a reference for the epidemiology of GoCV in Guangdong, understanding the elemental composition of the virus genes and proteins, selecting representative vaccine strains, constructing targeted immune preparations for GoCV, and strengthening prevention and control of the disease.

Influenza A virus is one of the most important zoonotic pathogens that can cause severe symptoms and has the potential to cause high number of deaths and great economic loss. Vaccination is still the best option to prevent influenza virus infection. Different types of influenza vaccines, including live attenuated virus vaccines, inactivated whole virus vaccines, virosome vaccines, split-virion vaccines and subunit vaccines have been developed. However, they have several limitations, such as the relatively high manufacturing cost and long production time, moderate efficacy of some of the vaccines in certain populations, and lack of cross-reactivity. These are some of the problems that need to be solved. Here, we summarized recent advances in the development and application of different types of influenza vaccines, including the recent development of viral vectored influenza vaccines. We also described the construction of other vaccines that are based on recombinant influenza viruses as viral vectors. Information provided in this review article might lead to the development of safe and highly effective novel influenza vaccines., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chen, Wang, Zhang and Ly.)

Four new H9N2 avian influenza viruses (AIVs) were isolated from domestic birds in Guangdong between December 2015 and April 2016. Nucleotide sequence comparisons indicated that most of the internal genes of these four strains were highly similar to those of human H7N9 viruses. Amino acid substitutions and deletions found in the HA and NA proteins indicated that all four of these new isolates may have an enhanced ability to infect humans and other mammals. A cross-hemagglutinin-inhibition assay, conducted with two vaccine strains that are broadly used in China, suggested that antisera against vaccine candidates could not provide complete inhibition of the new isolates.

The aim of this study was to evaluate the protective effects of SeY (selenium-rich yeast) against Al (aluminum)-induced inflammation and ionic imbalances. Male Kunming mice were treated with Al (10 mg/kg) and/or SeY (0.1 mg/kg) by oral gavage for 28 days. The degree of inflammation was assessed by mRNA expression of inflammatory biomarkers. Ionic disorders were assessed by determining the Na + , K + , and Ca 2+ content, as well as the alteration in ATP-modifying enzymes (ATPases), including Na + K + -ATPase, Ca 2+ -ATPase, Mg 2+ -ATPase, Ca 2+ Mg 2+ -ATPase, and the mRNA levels of ATPase's subunits in kidney. It was observed here that SeY exhibited a significant protective effect on the kidney against the Al-induced upregulation of pro-inflammatory and downregulation of anti-inflammatory cytokines. Furthermore, a significant effect of Al on the Na + , K + , Ca 2+ , and Mg 2+ levels in kidney was observed, and Al was observed to decrease the activities of Na + K + -ATPase, Mg 2+ -ATPase, and Ca 2+ Mg 2+ -ATPase. The mRNA expression of the Na + K + -ATPase subunits and Ca 2+ -ATPase subunits was regulated significantly by Al. Notably, SeY modulated the Al-induced alterations of ion concentrations, ATPase activity, and mRNA expression of their subunits. These results suggest that SeY prevents renal toxicity caused by Al via regulation of inflammatory responses, ATPase activities, and transcription of their subunits.

We report the full-length sequence of two chicken source influenza A (H7N9) viruses found in Guangdong live poultry market (LPM) during the most recent wave of human infections (from October 2016 to the present time). These viruses carry insertion of poly-basic amino acids (KGKRTAR/G) at the protease cleavage site of the HA protein, which were previously found in the highly pathogenic (HP) human influenza A (H7N9) [IAV(H7N9)] strains. Phylogenetic analysis of these two novel avian influenza viruses (AIVs) suggested that their genomes reassorted between the Yangtze River Delta (YRD) and Pearl River Delta (PRD) clades. Molecular clock analysis indicated that they emerged several months before the HP human strains. Collectively, our results suggest that IAV(H7N9) viruses evolve in chickens through antigenic drift to include a signature HP sequence in the HA gene, which highlights challenges in risk assessment and public health management of IAV(H7N9) infections at the human-animal interface.