Intracontinental and intercontinental dissemination of Asian H5 highly pathogenic avian influenza virus (clade 2.3.4.4) in the winter of 2014–2015

Abstract

Asian H5 highly pathogenic avian influenza viruses (HPAIVs) that possess the clade 2.3.4.4 HA gene have been identified in wild birds and poultry since late 2014 in both Europe and North America (N. America). Clade 2.3.4.4 H5 HPAIVs of the H5N8 subtype have been isolated in both regions, whereas reassortment viruses with NA N1 and N2 subtypes of the North American (N. American). avian lineage have only been identified in N. America. The HA genes of those isolates were closely related to genes of the HPAIVs that have caused massive outbreaks in poultry in Korea since January 2014. The outbreaks caused by those viruses and the genetic relatedness of their HA and NA genes are reviewed in this study. Although the illegal movement of poultry and poultry products cannot be ruled out as a cause of intercontinental and intracontinental dissemination of clade 2.3.4.4 H5 HPAIVs during the winter of 2014-2015, transmission of the viruses by infected migratory birds appears to be a more plausible mechanism for their dissemination. In particular, the involvement of migratory birds in HPAIV transmission between Asia and N. America is highly likely because of the reassortments between H5N8 HPAIV and the N. American lineage avian influenza viruses.

Sialic acid receptors: focus on their role in influenza infection

“…56 Clade 2 became predominant with an extensive intercontinental expansion of the Asian clade 2.3.4.4. 57,58 The expansion of the A/Goose/Guangdong/1/1996 lineage included outbreaks of H5N8 viruses in China and South Korea in 2014 and the first detection in the American continent, Canada, and USA of a highly pathogenic reassortant H5N2 virus. 59 A novel H5N6 virus emerged in China in 2014 causing human infections; this novel genotype has replaced the H5N1 as the dominant subtype in southern China.…”

Rapid acquisition of polymorphic virulence markers during adaptation of highly pathogenic avian influenza H5N8 virus in the mouse

“…However, a major antigenic shift in the H5N1 virus began in 2008 in China, with a highly pathogenic H5N5 virus3. A major, prolonged outbreak of HPAI H5 virus expressing the novel N8 gene began in South Korea in early 2014 and subsequently spread to Japan and Europe4. Moreover, the Eurasian HPAI H5N8 virus crossed from Eurasia to North America for the first time and created novel reassortants with North American viruses45.…”

“…A major, prolonged outbreak of HPAI H5 virus expressing the novel N8 gene began in South Korea in early 2014 and subsequently spread to Japan and Europe4. Moreover, the Eurasian HPAI H5N8 virus crossed from Eurasia to North America for the first time and created novel reassortants with North American viruses45. Rapid spread and reassortment events severely increase the risk of human infection and pandemic.…”

Workshop – Assessing risks of introduction of highly pathogenic avian influenza virus via wild birds

“…HPAIV expected to be introduced via this area belong mainly to the 2.3.4.4 clade (Saito et al, 2015;Marchenko et al, 2014;Bouwstra et al, 2015;Adlhoch et al, 2014;Verhagen et al, 2015;Harder et al, 2015); (ii) the east area (E), EU border from Ukraina to Cyprus, where migratory wild birds also enter the EU generally during the fall-winter migration but where detected HPAIV mainly belong to the 2.3.2.1c clade (Alkhamis et al, 2013;Marinova-Petkova et al, 2012); (iii) the south area (S), EU border from the southern of Portugal to Cyprus, across which migratory wild birds generally enter the EU from Africa during the spring migration and HPAIV belonging to clades 2.2.1.2 (endemic in Egypt) and 2.3.2.1c (prevalent in subSaharan West-African countries) would be expected (Arafa et al, 2015;Kammon et al, 2015;Monne et al, 2015). The north-west area (NW), where wild birds migrating from or across Greenland to EU, is not considered due to the quantitatively minor proportion of wild bird entries.…”

“…Source of information Lee et al, 2016;Li at al., 2014;Kanehira et al, 2015; Concentration of H5N8 virus excreted by a water bird in one standard dayexcretion is for 5 days, high loads are excreted for only 2 days. Peak titres are 1,000,000 TCID50/gr faeces (0.5 day); average titres over 5 days per gr faeces are 1,000…”