Friday, December 22, 2017

ECDC/EFSA/EU: Avian Influenza Overview September – November 2017


Last winter the EU endured their worst avian epizootic in history with the arrival of a recently reassorted HPAI H5N8 virus carried in by migratory birds from Russia and China, which resulted in roughly 1200 H5 HPAI outbreaks in poultry and captive birds, and nearly 1500 HPAI detections in wild birds (see ECDC/EFSA Joint Report: Avian Influenza Overview Oct 2016–Aug 2017).
While avian flu in Europe - and around the globe - has certainly not gone away, so far this fall we've seen more in the way of sporadic outbreaks, rather than fast moving epizootics.
Instead of seeing the expected return of H5N8 to Europe, we've seen the tentative arrival of a new H5N6 reassortment (see Netherlands Bird Flu Identified As Reassorted H5N6), an emerging strain that also showed up in East Asia (Japan, South Korea, Taiwan) in mid-to-late November.

H7N9 has yet to make an impact in China this fall, and we've only seen one human H5N6 infection reported over the past 12 months.  H5N1, while certainly active among poultry in Africa, parts of Asia, and the Middle East - has been similarly subdued when it comes to human cases over the past year.
These lulls in avian flu activity - while always welcome - are hardly unique (for an overview of this on-again, off-again pattern see H5N8: A Case Of Deja Flu?) and are unlikely to persist for long. 
While we wait to see what comes next, the EFSA/ECDC/EU has released a highly detailed 56-page overview (with historical context) of avian flu activity around the globe from September 1st to November 15th of this year.  This release also contains two Annexes (A&B) that deal specifically with Italy's summer resurgence of HPAI H5N8.
Due to the November 15th cutoff date of this overview, the reassorted H5N6 virus that was first announced in late November (see South Korea: Gochang HPAI H5N6 A New Reassortant Virus), and subsequenlty in Japan, Taiwan, and The Netherlands is not included. 
Nevertheless this document provides a terrific overview of where we are with both LPAI and HPAI avian flu around the globe, and is very much worth keeping on hand as a reference guide.  At least until the next update.

Avian influenza overview September – November 2017

European Food Safety Authority,
European Centre for Disease Prevention and Control and
European Union Reference Laboratory for Avian influenza

Ian Brown, Thijs Kuiken, Paolo Mulatti, Krzysztof Smietanka, Christoph Staubach, David Stroud, Ole Roland Therkildsen, Preben Willeberg, Francesca Baldinelli, Frank Verdonck and Cornelia Adlhoch


Between 1 September and 15 November 2017, 48 A(H5N8) highly pathogenic avian influenza (HPAI) outbreaks in poultry holdings and 9 H5 HPAI wild bird events were reported within Europe. A second epidemic HPAI A(H5N8) wave started in Italy on the third week of July and is still ongoing on 15 November 2017.

The Italian epidemiological investigations indicated that sharing of vehicles, sharing of personnel and close proximity to infected holdings are the more likely sources of secondary spread in a densely populated poultry area. Despite the ongoing human exposures to infected poultry during the outbreaks, no transmission to humans has been identified in the EU.

The report includes an update of the list of wild bird target species for passive surveillance activities that is based on reported AI-infected wild birds since 2006. The purpose of this list is to provide information on which bird species to focus in order to achieve the most effective testing of dead birds for detection of H5 HPAI viruses.
Monitoring the avian influenza situation in other continents revealed the same risks as in the previous report (October 2016-August 2017): the recent human case of HPAI A(H5N6) in China underlines the continuing threat of this avian influenza virus to human health and possible introduction via migratory wild birds into Europe.

Close monitoring is required of the situation in Africa with regards to HPAI of the subtypes A(H5N1) and A(H5N8), given the rapidity of the evolution and the uncertainty on the geographical distribution of these viruses. Interactions between EFSA and member states have taken place to initiate discussions on improving the quality of data collections and to find a step-wise approach to exchange relevant (denominator) data without causing an additional resource burden.

         4. Conclusions
HPAI and LPAI outbreaks in Europe between 1 September and 15 November 2017 (TOR 1 and TOR 2)
Main observations:
  • To date, no human infections with HPAI or related LPAI viruses have been reported in the EU.
  • In the EU, between 1 September and 15 November 2017 (based on ADNS):
  • 48 HPAI A(H5N8) outbreaks were reported in poultry: 44 in Italy and 4 in Bulgaria,
  • there were no H5 HPAI outbreaks in captive birds,
  • 7 H5 HPAI events were reported in wild birds in 3 MSs (1 in Cyprus, 1 in Germany and 5 in Italy) and in 2 events in Switzerland,
  • 6 H5 LPAI outbreaks were reported in poultry in 3 MSs (4 in Italy, 1 in France, 1 in the Netherlands) and 1 H5 LPAI outbreak in captive birds in Germany.
  • A second epidemic wave started in Italy on the third week of July and is still ongoing as of 15 November 2017; 63 outbreaks in poultry (mainly turkey) holdings and 7 events in wild birds were confirmed as caused by HPAI viruses of A(H5N8) subtype. Around half of the outbreaks were caused by secondary spread.
  • HPAI A(H5N8) induced high mortality in chickens and turkeys but variable (low to high) mortality in ducks, geese and game birds.
  • The risk of zoonotic transmission to the general public in the EU/EEA countries is considered to be very low.
  • Despite the ongoing human exposures to infected poultry during the outbreaks, no transmission to humans has been identified.
  • The HPAI A(H5N8) virus persisted during winter into the late summer at least and still results in wild bird infections and in primary introductions in poultry holdings. It suggests that the virus is able to persist in the EU in wild bird populations, the environment, or both, during the period between two winters.
  • An update of the list of wild bird target species for passive surveillance activities is provided based on the reported AI-infected wild birds since 2006.

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