Avian influenza A(H5N6): the latest addition to emerging zoonotic avian influenza threats in East and Southeast Asia

Context of new emerging subtypes of Avian Influenza viruses in eastern Asia The first reported appearance of a global zoonotic influenza of avian origin dates from 1996, when an outbreak of H5N1 highly pathogenic avian influenza (HPAI) occurred on a goose farm in Guangdong Province, China [Guan et Smith, 2013]. One year later, the H5N1 HPAI virus was recognised as a zoonotic agent with 18 human cases identified in Since early 2013 several new avian influenza virus strains have been reported in East and Southeast Asia, threatening both poultry-dependant livelihoods and human health. In March 2013, avian influenza A(H7N9) emerged in China causing a total of 456 human cases, and claiming 172 lives as of 05 November 2014. The virus is of low pathogenicity in poultry (no clinical signs are observed in infected birds) but can cause lethal pulmonary infection in mammals without prior trans-species adaptation [Can et al, 2014]. Subsequently, H10N8 was reported in December 2013, causing three human cases in China, including two fatalities, while H5N8 emerged the month after and was the cause of at least 40 poultry outbreaks, mainly in the Republic of Korea but also in Japan and China [OIE; EMPRES-i]. This was followed by the first reports from China and Lao People’s Democratic Republic in early May 2014, describing outbreaks in poultry caused by a highly pathogenic H5N6. More recently, the finding of a H5N3 subtype was reported for the first time on 24 October 2014 from a live bird market in Changsha, Hunan, China [OIE]. Concerns grow as the rate of emergence of new sub-types increases, creating new potential threats and a need for continuous vigilance and monitoring (Table 1 and Figure 1).