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Outbreaks of highly pathogenic avian influenza (HPAI) in poultry and wild birds are a growing problem in Western Europe and large parts of the world. The currently prevaling theory is that migrating waterfowl play a key role in the continental spread and regional dynamics of the virus. At the Netherlands Institute of Ecology I have been involved in the monitoring of HPAI in wild waterfowl during the outbreaks of 2014-2015 and 2016-2017 and after starting at Sovon in 2018 I've been active in the bird diseases research group.

 

Large HPAI outbreak among Black-headed Gulls in the Netherlands (2023)

Starting winter 2022-2023 an HPAI outbreak has been building up in Black-tailed Gulls, causing large-scale mortality in breeding colonies over the course of the spring and summer. The AI-Impact working group, a consortium of researchers and site managers, is closely monitoring the impact of the outbreak.

Likely HPAI-infected lethargic Black-headed Gull on a path in a nature reserve in the Netherlands. (photo: Erik Kleyheeg)

 

HPAI-related mass mortality among Sandwich Terns in the Netherlands (2022)

2022 was the first year that the HPAI avian influenza virus kept circulating in wild birds during the breeding season, confronting summer migrants with the virus for the first time. Sandwich Terns, breeding in dense colonies, were hit hardest. Casrcass recoveries in the colonies (i.e. excluding carcasses that were not recovered) already showed that over 20% of the adult birds of the breeding population had parished. The outbreak was well documented by the AI-Impact working group, resulting in a scientific publication in Emerging Infectious Diseases (see below).
 
Sandwich Tern with HPAI symptoms in 2022. (photo: Romke Kleefstra)
 
Rijks JM, Leopold MF, Kühn S, in ‘t Veld R, Schenk F, Brenninkmeijer A, Lilipaly SJ, Ballmann MZ, Kelder L, de Jong JW, Courtens W., Slaterus R., Kleyheeg E., et al. (2022) Mass mortality caused by highly pathogenic influenza A (H5N1) virus in Sandwich terns, the Netherlands, 2022. Emerging Infectious Diseases, 28(12):2538-42. (pdf)

 

First reported HPAI-related mass mortality among wild birds in the Netherlands (2016-2017)

Kleyheeg E, Slaterus R, Bodewes R, Rijks JM, Spierenburg MA, Beerens N, Kelder L, Poen MJ, Stegeman JA, Fouchier RA, Kuiken T. Deaths among wild birds during highly pathogenic avian influenza A (H5N8) virus outbreak, the Netherlands. Emerging infectious diseases. 2017 Dec;23(12):2050. (pdf)
 

Main figure from Kleyheeg et al. (2017) depicting the courrse of the HPAI outbreak with mainly Tufted Duck carcasses reported in November in the Markermeer region, followed by a more widespread Eurasian Wigeon mortality in December.

 

Common Pochard, H5N8 victim at Gouwzee 01-12-2016. (photo: Erik Kleyheeg)

 

Publications in the avian influenza project