Role of domestic ducks in the emergence of a new genotype of highly pathogenic H5N1 avian influenza A viruses in Bangladesh

Abstract

Highly pathogenic avian influenza H5N1 viruses were first isolated in Bangladesh in February 2007. Subsequently, clades 2.2.2, 2.3.4.2 and 2.3.2.1a were identified in Bangladesh, and our previous surveillance data revealed that by the end of 2014, the circulating viruses exclusively comprised clade 2.3.2.1a. We recently determined the status of circulating avian influenza viruses in Bangladesh by conducting surveillance of live poultry markets and waterfowl in wetland areas from February 2015 through February 2016. Until April 2015, clade 2.3.2.1a persisted without any change in genotype. However, in June 2015, we identified a new genotype of H5N1 viruses, clade 2.3.2.1a, which quickly became predominant. These newly emerged H5N1 viruses contained the hemagglutinin, neuraminidase and matrix genes of circulating 2.3.2.1a Bangladeshi H5N1 viruses and five other genes of low pathogenic Eurasian-lineage avian influenza A viruses. Some of these internal genes were closely related to those of low pathogenic viruses isolated from ducks in free-range farms and wild birds in a wetland region of northeastern Bangladesh, where commercially raised domestic ducks have frequent contact with migratory birds. These findings indicate that migratory birds of the Central Asian flyway and domestic ducks in the free-range farms in Tanguar haor-like wetlands played an important role in the emergence of this novel genotype of highly pathogenic H5N1 viruses.

Epidemiology of duck as reservoir of Avian Influenza Virus in Bangladesh

“…This factor may contribute to the infection to the native and commercial poultry industry (Alexander, 2003;De Marco et al, 2003). This result also revealed that migratory birds and domestic ducks in haor area played an important role in the emergence novel genotype of highly pathogenic avian influenza virus (AIV) (Barman et al, 2017). Ducks are the natural reservoir of influenza A virus (Khatun et al, 2013) that strongly support this research work.…”

Domestic ducks play a major role in the maintenance and spread of H5N8 highly pathogenic avian influenza viruses in South Korea

“…The increase in number of sequences will be helpful to increase the accuracy and credibility of this model. Many previous studies also have indicated domestic duck as a major source of HPAIV based on phylogenetic and epidemiological analysis (Barman et al, ; Gilbert et al, , ; Guinat et al, ; Hill et al, ; Pfeiffer, Minh, Martin, Epprecht, & Otte, ). Consistent with our data, domestic waterfowl seemed to play a major role in recent huge outbreaks of H5 HPAIVs, especially clade 2.3.4.4 H5NX HPAIVs.…”

“…The increase in number of sequences will be helpful to increase the accuracy and credibility of this model. Many previous studies also have indicated domestic duck as a major source of HPAIV based on phylogenetic and epidemiological analysis (Barman et al, 2017;Gilbert et al, 2006Gilbert et al, , 2010Guinat et al, 2019;Hill et al, 2015;Pfeiffer, Minh, Martin, Epprecht, & Otte, 2007 HPAIV had been dominant strains from 2014 and domestic ducks and geese suspected as a major source of H5N6 viruses (Bi et al, 2016). Many previous in vivo infection studies in birds showed that clade 2.3.4.4 H5NX HPAI viruses more efficiently replicated in domestic and wild waterfowl than chickens but did not induce high mortality in waterfowl Kwon et al, 2018;Pantin-Jackwood et al, 2017;Pantin-Jackwood et al, 2016;Sun et al, 2016;van den Brand et al, 2018).…”

Avian influenza overview September – November 2017

“…Intraclade and interclade reassortants of Gs/Gd/96-like A(H5N1) have been described (Marinova-Petkova et al, 2016a). Recently, a novel genotype containing HA, NA and M genes from the A(H5N1) clade 2.3.2.1a and the remaining genes of the Eurasian-origin LPAIV has been described in Bangladesh (Barman et al, 2017). There is also evidence of the intersubtype reassortments (including A(H5N1)/A(H9N2)) of clades 2.3.2.1a (Marinova-Petkova et al, 2016b) or 7.2 .…”