Differences in Highly Pathogenic H5N6 Avian Influenza Viral Pathogenicity and Inflammatory Response in Chickens and Ducks

Abstract

Infection with H5N6 highly pathogenic avian influenza virus caused high mortality in chickens, while ducks often appear to be asymptomatic. But, some recent H5Nx subtype viruses could cause high mortality in ducks. The variation between different species and the mechanisms by which some H5Nx viruses cause death in ducks requires investigation to identify the key processes in influenza susceptibility and pathogenesis. Here, we characterized two representative H5N6 viruses, A/Pavo cristatus/Jiangxi/JA1/2016 (JA1) and A/Anas crecca/shanghai/SH1/2016 (SH1), and compared their pathogenicity and expression profiles of immune-related genes in chickens and ducks to identify the elements of the host immune-related response that were involved in disease lethality. Results suggested that H5N6 HPAIVs had higher pathogenic and inflammatory effect in chickens than in ducks. Importantly, the TNF-α, IL-6, IFN-γ and iNOS levels were significantly higher in the lung of SH1 infected chickens compared to those of ducks. And we found higher systemic levels of IL-6 induced by JA1 in chickens than in ducks. In addition, our experiments demonstrated that JA1 was associated with greater pathogenicity in ducks were accompanied by the excessive expression of iNOS in the brain. These results are helpful to understand the relationship between the pathogenicity of H5N6 AIVs and inflammatory responses to them in chickens and ducks.

Susceptibility of Common Family Anatidae Bird Species to Clade 2.3.4.4e H5N6 High Pathogenicity Avian Influenza Virus: An Experimental Infection Study

“…Similar results have been reported in Mandarin ducks with clade 2.3.4.4e H5N6 HPAIVs [24,33]. In another study, most mallards died of infection within 8 weeks after being infected with clade 2.3.4.4e A/Pavo cristatus/Jiangxi/JA1/2016 (H5N6) [25], while those infected with another clade 2.3.4.4 strain, A/Anas crecca/shanghai/SH1/2016 (H5N6), caused no signs of infection. These results suggest that pathogenicity of clade 2.3.4.4e HPAIVs in Anatidae varies depending on the strain.…”

“…Little is known about the pathogenicity of clade 2.3.4.4e HPAIVs in Anatidae. Mandarin ducks inoculated with the clade 2.3.4.4e HPAIVs showed inapparent infection with virus shedding via the oral route [24]; Wang et al [25] reported that some 2.3.4.4e HPAIVs demonstrated relatively higher pathogenicity in mallards, accompanied by the excessive expression of iNOS in the brain.…”

Phylogenetic and Pathogenicity Comparison of Three H5N6 Avian Influenza Viruses in Chickens, Ducks and Mice

“…In this study, the amino acid sequences at the cleavage sites of the HA genes of 3 isolates were all continuous basic amino acids, which was in line with the characteristics of highly pathogenic avian influenza virus (HPAIV) [13]. Previous studies have shown that amino acid mutations such as S133A, I151T, T156S, Q222L, S/R223N, G224S, P235S and E251K can change the affinity of AIV for human and avian receptors, especially the mutations of Q222L and G224S were the most critical [14]. In our study, amino acids Q222 and G224 of the HA proteins of the 3 viruses were not mutated (Table 1), so they retained the ability to bind to the avian receptor α2-3 galactosylsialic acid (SAα2-3Gal).…”

Susceptibility of common family Anatidae bird species to clade 2.3.4.4e H5N6 high pathogenicity avian influenza virus: an experimental infection study

“…Similar results have been reported in Mandarin ducks with clade 2.3.4.4e H5N6 HPAIVs [ 24 , 33 ]. In another study, most mallards died of infection within 8 weeks after being infected with clade 2.3.4.4e A/ Pavo cristatus /Jiangxi/JA1/2016 (H5N6) [ 25 ], while those infected with another clade 2.3.4.4 strain, A/ Anas crecca /shanghai/SH1/2016 (H5N6), caused no signs of infection. These results suggest that pathogenicity of clade 2.3.4.4e HPAIVs in Anatidae varies depending on the strain.…”

“…Little is known about the pathogenicity of clade 2.3.4.4e HPAIVs in Anatidae. Mandarin ducks inoculated with the clade 2.3.4.4e HPAIVs showed inapparent infection with virus shedding via the oral route [ 24 ]; Wang et al [ 25 ] reported that some 2.3.4.4e HPAIVs demonstrated relatively higher pathogenicity in mallards, accompanied by the excessive expression of iNOS in the brain.…”