Genetic and molecular characterization of H9N2 and H5 avian influenza viruses from live poultry markets in Zhejiang Province, eastern China

Abstract

Live poultry markets (LPMs) are a key source of reassorted avian influenza viruses (AIVs) because of the density of terrestrial and aquatic poultry and the frequency of AIV infection. H9N2 viruses are prevalent in terrestrial poultry throughout Asia and have been isolated from poultry outbreaks worldwide. They infect both avian and mammalian species and may be significant donors of genetic material to emerging human pathogens. LPMs in Zhejiang Province were surveyed from 2013–2014 for AIVs. Three hundred seventy-four (374) AIV strains were isolated from 3,328 samples. Whole–genome sequencing and phylogenetic analyses were performed. We identified a novel H9N2 virus genotype that had undergone reassortment with gene segments from Qa/HK/G1/97–like, Ck/BJ/1/94–like, and Dk/HK/Y439/97–like viruses. Phylogenetic analyses suggested the H9N2 viruses had undergone reassortments with other AIV subtypes. The results also suggested that two different clades (2.3.2 and 2.3.4.6) of H5 viruses were co–circulating in Zhejiang Province. Given that reassorted H5 AIVs were detected in geese and ducks, it is possible that apparently healthy birds contribute to emerging H5 AIVs. Continued surveillance is required in poultry in eastern China.

Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections

“…The potential for reassortment between AIVs, including A/H5N1, could result in the emergence of viral strains with considerable impacts on poultry and/or human health. This study, coupled with other recent studies in LBMs from other Asian countries, [15][16][17] confirms that the environment of LBMs provides a pool of genes for potential emergence of new pandemic viruses. The silent circulation of a multitude of LPAI viruses, which remain undetected and unmonitored in most Asian countries, heightens the threat when they co-circulate with pandemic candidates such as A/H5N1 and A/H7N9.…”

“…12 Previous studies have established that LBMs serve as hubs for the circulation and persistence of AIVs through the presence of multiple avian species, the constant introduction of immunologically naive hosts and the frequent lack of biosecurity measures. 1,13,14 Recent surveillance studies have documented that A/H5N1 and A/H7N9 commonly co-circulate with other subtypes of avian influenza in LBMs, [15][16][17] thus increasing the likelihood of reassortment events.…”

Insight into live bird markets of Bangladesh: an overview of the dynamics of transmission of H5N1 and H9N2 avian influenza viruses

“…H9N2 viruses donated their internal genes to several H5 and H7 viruses of public health concern. 22 It has also been previously shown 12 that chicken H9N2 in Bangladesh is antigenically conserved compared to quail H9N2 which shows antigenic drift. H9N2 viruses tend to evolve rapidly and acquire mutations that confer replication in mammalian hosts, much like H5N1 isolated from Bangladesh.…”

Genesis and Dissemination of Highly Pathogenic H5N6 Avian Influenza Viruses

“…It is probable that the reassortment pathway of the H5N6 virus was due to the epidemic of clade 2. viruses, through interaction between migratory birds and local poultry. H5N6 viruses could further exchange gene segments with viruses circulating in poultry, especially in live-poultry markets (16,35,36).…”