Reintroduction of H5N1 highly pathogenic avian influenza virus by migratory water birds, causing poultry outbreaks in the 2010–2011 winter season in Japan

Abstract

Reintroduction of H5N1 highly pathogenic avian influenza virus by migratory water birds, causing poultry outbreaks in the

H5N1 highly pathogenic avian influenza virus isolated from conjunctiva of a whooper swan with neurological signs

“…All of the genes of this isolate were similar to those of other H5N1 viruses isolated in Japan in 2011 [16], and they were also closely related to those of Mongolian and Korean strains isolated in 2009-2010 and 2010-2011, respectively ( Table 2). The HA cleavage site sequence of Ws/HN/11 has the typical sequence motif of a virulent type, SPQRERRRKR/GLF.…”

“…The isolate fell into clade 2.3.2.1, similar to other H5N1 strains isolated in Japan, Mongolia, and Korea between 2008 and 2011 [16]. The H5N1 strains isolated in Japan in 2008 form a single branch separated from the 2011 strains including Ws/HN/11 in clade 2.3.2.1 (Fig.…”

“…The H5N1 strains isolated in Japan can be divided into three disparate clades: 2.5, 2.2 and 2.3.2.1. The results seem to suggest that H5N1 viruses circulating in Asian countries are undergoing genetic change, possibly by antigenic drift and/or positive selection under immunological pressures as described by Sakoda et al [16]. Continuous efforts for characterizing the viral genes of the influenza virus variants should be of extreme importance.…”

“…Importantly, isolation of the H5N1 virus from the fecal samples of ducks at Lake Onuma, Hokkaido, in October 2010 is regarded as the earliest case of viral isolation. Subsequently, the H5N1 virus was isolated from 63 wild birds in 17 prefectures throughout Japan [16]. There has been an increasing interest in the ecology of wild birds, since AIVs are known to spread during their migration period [12,20].…”

Two novel reassortants of avian influenza A (H5N6) virus in China

“…Since then, transmission of H5N1 viruses from avian hosts to humans has been reported in 17 countries and areas worldwide, leading to 676 laboratory-confirmed infections and 398 deaths as of 4 December 2014 (WHO, 2014a). Importantly, the H5N1 virus can infect migratory birds, which act as vectors that contribute to the spread of the virus to new areas via long-distance migration and transmission to domestic poultry through direct or indirect contact (Liu et al, 2005;Sakoda et al, 2012;Wang et al, 2008). Since its emergence, the HPAI H5N1 virus has been proposed as a likely candidate for a potential influenza pandemic, although effective human-to-human transmission is yet to be demonstrated.…”