Spatial transmission of H5N6 highly pathogenic avian influenza viruses among wild birds in Ibaraki Prefecture, Japan, 2016–2017

Abstract

From 29 November 2016 to 24 January 2017, sixty-three cases of H5N6 highly pathogenic avian influenza virus (HPAIV) infections were detected in wild birds in Ibaraki Prefecture, Japan. Here, we analyzed the genetic, temporal, and geographic correlations of these 63 HPAIVs to elucidate their dissemination throughout the prefecture. Full-genome sequence analysis of the Ibaraki isolates showed that 7 segments (PB2, PB1, PA, HA, NP, NA, NS) were derived from G1.1.9 strains while the M segment was from G1.1 strains; both groups of strains circulated in south China. Pathological studies revealed severe systemic infection in dead swans (the majority of dead birds and the only species necropsied), thus indicating high susceptibility to H5N6 HPAIVs. Coalescent phylogenetic analysis using the 7 G1.1.9-derived segments enabled detailed analysis of the short-term evolution of these highly homologous HPAIVs. This analysis revealed that the H5N6 HPAIVs isolated from wild birds in Ibaraki Prefecture were divided into 7 groups. Spatial analysis demonstrated that most of the cases concentrated around Senba Lake originated from a single source, and progeny viruses were transmitted to other locations after the infection expanded in mute swans. In contrast, within just a 5-km radius of the area in which cases were concentrated, three different intrusions of H5N6 HPAIVs were evident. Multi-segment analysis of short-term evolution showed that not only was the invading virus spread throughout Ibaraki Prefecture but also that, despite the small size of this region, multiple invasions had occurred during winter 2016-2017.

Carriage and potential long distance transmission of Listeria monocytogenes by migratory black-headed gulls in Dianchi Lake, Kunming

“…Migratory birds are susceptible to various pathogens such as Avian influenza virus, Salmonella and Campylobacter [8,15–18,26]. Some wild water birds like black-headed gull could be the ultimate source of Influenza A virus and natural reservoir of potentially other pathogens, and spread the pathogens to poultry, mammals and humans [18,27]. In China, black-headed gulls migrate from Xinjiang, Mongolia and Siberia to Dianchi Lake of Kunming every year (Figure 3).…”

Subclinical Infection and Transmission of Clade 2.3.4.4 H5N6 Highly Pathogenic Avian Influenza Virus in Mandarin Duck (Aix galericulata) and Domestic Pigeon (Columbia livia domestica)

“…Viruses 2021, 13, 1069 2 of 12 After the initial emergence from China in 2013, clade 2.3.4.4 H5N6 HPAI virus spread to Laos and Vietnam during 2014-2015, eventually being well established in the countries [10][11][12], and more eastward to Japan and South Korea during 2016-2017 [13,14]. The clade 2.3.4.4 HPAI H5N6 viruses, which have been the dominant subtype in China, have evolved into multiple genotypes and caused infection in multiple species, including mammalian species and humans [15][16][17][18]. From 2014 to March 2021, 30 cases of laboratoryconfirmed human infection by H5N6 HPAIV, including 8 fatal cases, have been reported to the World Health Organization (WHO) [19].…”

Comparative pathogenicity of H5N6 subtype highly pathogenic avian influenza viruses in chicken, Pekin duck and Muscovy duck

“…Prior to the first poultry outbreak in this season, a H5N6 HPAIV was detected in the faeces of a Northern Pintail ( Anas acuta ) on November 6, 2016. In total, 218 cases of H5N6 HPAIV infection in wild birds, including captive and zoological birds, were reported until March 8, 2017 (Ministry of Environment Government of Japan, and Tsunekuni et al., ). The period of poultry outbreaks overlapped with that of the H5N6 HPAIV detection in wild birds.…”