Avian influenza overview November 2019– February2020

Abstract

Between 16 November 2019 and 15 February 2020, 36 highly pathogenic avian influenza (HPAI) A(H5N8) virus outbreakswere reported in Europe in poultry (n=34), captive birds (n=1) and wild birds (n=2), in Poland, Hungary, Slovakia, Romania, Germany, Czechiaand Ukraine,one HPAI outbreakcaused by a simultaneous infection with A(H5N2) and A(H5N8) was reported in poultry in Bulgaria, andtwo low pathogenic avian influenza (LPAI) A(H5) virus outbreaks were reported in poultryin the United Kingdom and in Denmark. Genomic characterisation of the HPAI A(H5N8) viruses suggests that they are reassortants of HPAI A(H5N8) viruses from Africa and LPAI viruses from Eurasia. It is likely that this reassortment occurred in wild migratory birds in Asia during the summer and then spread to eastern Europe with the autumnmigration. This is the first time that wild bird migration from Africa to Eurasia has been implicated in the long‐distance spread of HPAI viruses to the EU. Given the late incursion of HPAI A(H5N8) virus into the EU in this winter season (first outbreak reported on 30 December 2019), its overall restriction to eastern Europe, and the approaching spring migration, the risk of the virus spreadingfurther in the west via wild birds is decreasing for the coming months. Genetic analysis of the HPAI A(H5N2) and A(H5N8) viruses detected in the Bulgarian outbreak reveals that these virusesare both related to the 2018‐19 Bulgarian HPAI A(H5N8) viruses and not to the HPAI A(H5N8) viruses currently circulating in Europe.An increasing number of HPAI A(H5N1), A(H5N2), A(H5N5) and A(H5N6) virus outbreaks in poultry in Asia were reported during the time period for this report compared with the previous reporting period. Single outbreaks of HPAI A(H5N8) virus were notified by Saudi Arabia and South Africa. Furthermore, in contrast to the last report, HPAI virus‐positive wild birds were reported from Israel and one of the key migration areas in northern China.Two human cases due to A(H9N2) virus infection were reported during the reporting period.

The genetics of highly pathogenic avian influenza viruses of subtype H5 in Germany, 2006–2020

“…The incursion of the novel clade 2.3.4.4b HPAIV H5N8 into Europe in late 2019/early 2020 most likely follows a similar pattern to the previously described clade 2.3.4.4 situation (Lycett et al, 2020). After the probable initial migratory bird dissemination of the virus from Eurasia and/or Africa into East and Central Europe, local dissemination and thus detached evolution of the reassortant led to partitioning of the described clusters (Adlhoch et al, 2020).…”

“…This includes Asia/Eurasia, Europe and Africa (Abolnik et al, 2019;Fusaro et al, 2017;Kwon et al, 2018;Nagarajan et al, 2017;Voronina et al, 2018;Yehia et al, 2018). Slightly higher identity levels of 98.9%-99.6% were detected for the PB2, PA, HA, MP and NS segments in combination with a Nigerian HPAIV H5N8 isolate detected in July 2019 (Adlhoch et al, 2020).…”

“…Close relations could likewise be established between Hungarian (A/turkey/ Hungary/1020/20VIR749-1/2020, commercial holding), Polish (A/ hawk/Poland/003/2020, wild; A/turkey/Poland/23/2019, commercial holding), Czech (A/turkey/Czech Republic/3071/2020, commercial holding) and German (A/white-fronted goose/Germany-BB/ AI00018/2020; A/turkey/Germany-ST/AI00352/2020, commercial holding) sequences. A third cluster consisting of HPAIV H5N8 from the Czech Republic (A/chicken/Czech Republic/1175-1/2020, smallholding) and Germany (A/chicken/Germany-BW/AI00049/2020, smallholding; A/turkey/Germany-NI/AI00334/2020, commercial holding) was also detected (Figure S4; Adlhoch et al, 2020;King et al, 2020). The incursion of the novel clade 2.3.4.4b HPAIV H5N8 into Europe in late 2019/early 2020 most likely follows a similar pattern to the previously described clade 2.3.4.4 situation (Lycett et al, 2020).…”

“…A green sandpiper isolate sampled in the Kurgan region of Central Russia, August 2018, shared, for example identity levels of more than 99% with segment PB2. Equal identity values were established for the NP segment from a LPAIV H3N8 detected in a gadwall sampled at Lake Chany, Russia, October 2018 (Figure S2; Adlhoch et al, 2020;King et al, 2020).…”

Disease Outbreak, Health Scare, and Distance Decay: Evidence from HPAI Shocks in Chinese Meat Sector

“…According to official statistics, human infections with H5N1 occur across 16 countries and regions worldwide, with 856 global confirmed human infection cases reported by 16 January 2017; while human infections with H7N9 occur mostly in China, with 1115 global confirmed human infection cases reported by 8 January 2017. As covered by European Food Safety Authority (EFSA), from 16 November 2019 to 15 February 2020, 36 HPAI A(H5N8) outbreaks were reported in Europe in poultry (n = 34), wild birds (n = 2), and captive birds (n = 1), in Germany, Romania, Poland, Hungary, Slovakia, Czechia, and Ukraine; one HPAI outbreak caused by A(H5N2) and A(H5N8) was reported in poultry in Bulgaria; two A(H5) outbreaks were reported in poultry in Denmark and the United Kingdom; an increasing number of HPAI A(H5N1), A(H5N2), A(H5N5), and A(H5N6) outbreaks in poultry in Asia were reported compared with the previous reporting period; and two human infection cases caused by A(H9N2) were reported during this period [6].…”