Characterizing the temporal patterns of avian influenza virus introduction into Japan by migratory birds

Abstract

The objectives of the present study were to observe the temporal pattern of avian influenza virus (AIV) introduction into Japan and to determine which migratory birds play an important role in introducing AIV. In total, 19,407 fecal samples from migratory birds were collected at 52 sites between October 2008 and May 2015. Total nucleic acids extracted from the fecal samples were subjected to reverse transcription loop–mediated isothermal amplification to detect viral RNA. Species identification of host migratory birds was conducted by DNA barcoding for positive fecal samples. The total number of positive samples was 352 (prevalence, 1.8%). The highest prevalence was observed in autumn migration, and a decrease in prevalence was observed. During autumn migration, central to southern Japan showed a prevalence higher than the overall prevalence. Thus, the main AIV entry routes may involve crossing the Sea of Japan and entry through the Korean Peninsula. Species identification was successful in 221 of the 352 positive samples. Two major species sequences were identified: the Mallard/Eastern Spot-billed duck group (115 samples; 52.0%) and the Northern pintail (61 samples; 27.6%). To gain a better understanding of the ecology of AIV in Japan and the introduction pattern of highly pathogenic avian influenza viruses, information regarding AIV prevalence by species, the prevalence of hatch-year migratory birds, migration patterns and viral subtypes in fecal samples using egg inoculation and molecular-based methods in combination is required.

Genetic Characterization of Avian Influenza A (H11N9) Virus Isolated from Mandarin Ducks in South Korea in 2018

“…According to the phylogenetic tree of HA and NA, the newly identified H11N9 clustered with the same strains as the most genetically similar strain (A/A/duck/Kagoshima/KU57/2014 (H11N9) rather than with Korean H11N9 found in 2016 and 2014-2015; dead spot-billed ducks carried two AIVs of the H11N9 subtype in the Izumi plain [70]. As spot-billed ducks are widely distributed in the west and along the southern coastline in Korea, Japan, China, and Russia [71], this bird may be one of the hosts that migrated to Korea with the H11N9 reassortant in 2016-2017 ( Figure 3). Furthermore, our H11N9 had a lower in vitro titer in MDCK cells than A/California/04/2009 (H1N1), supporting the LPAI characterization of H11N9.…”

Satellite telemetry tracks flyways of Asian Openbill storks in relation to H5N1 avian influenza spread and ecological change

“…Nevertheless, the gulls flew across 7 countries that faced the problem of H5N1 AI outbreaks. The role of migratory birds on AI spread has been suggested in many studies [ 19 – 21 ].…”

Countermeasures for avian influenza outbreaks among captive avian collections at zoological gardens and aquariums in Japan

“…The highest prevalence rates were recorded between October and December each year, just after the autumn migration. Onuma et al, 3 showed that three routes were likely responsible for the introduction of the AI viruses to Japan, with the direct crossing of the Sea of Japan and entry through the Korean Peninsula identified as the two main routes. In addition, the study showed that the so-called mallards-eastern spot-billed duck group (Anas platyrhynchos and/or Anas zonorhyncha) and Northern pintails (Anas acuta) were the species most likely to have carried the AI viruses into Japan.…”