Systemic infection with highly pathogenic H5N8 of avian origin produces encephalitis and mortality in wild mammals at a UK rehabilitation centre

Abstract

Europe has experienced extensive outbreaks of highly pathogenic avian influenza (HPAI) during the autumn/winter 2020/21 season. These avian influenza A viruses are highly transmissible and have infected over 1000 commercial and backyard poultry premises in Europe in this period causing high mortality. The impact on wild bird populations has also been significant, with over 400 detections in at least 47 different species reported across Europe as being positive with the H5N8 virus. Although different H5Nx combinations within the H5 clade 2.3.4.4b have been detected, the H5N8 subtype has predominated both in wild birds and domestic poultry outbreaks. In the UK there have been 22 outbreaks of H5N8 in domestic poultry and captive birds and more than 300 wild bird detections involving H5N8 over the autumn/winter 2020/21 period to April 2021. Here we detail the series of events surrounding the detection of an H5N8 influenza A virus of avian origin in five swans, a fox and three seals in a wildlife rehabilitation centre.

Highly pathogenic avian influenza virus incursions of subtype H5N8, H5N5, H5N1, H5N4, and H5N3 in Germany during 2020-21

“…After detection of a clade 2.3.4.4b HPAIV H5N8 in Russian poultry workers in December 2020 ( Pyankova et al. 2021 ), and detection of the same reassortant (Ger-10-20-N8) in other mammalian species in a wildlife rehabilitation centre in the UK ( Floyd et al. 2021 ) and dead seals in Germany ( Postel et al.…”

Multiple Introductions of Reassorted Highly Pathogenic Avian Influenza H5Nx Viruses Clade 2.3.4.4b Causing Outbreaks in Wild Birds and Poultry in The Netherlands, 2020-2021

“…In addition, sporadic spillover of the virus to mammals was observed. HPAI H5 viruses were detected in red foxes in the Netherlands ( 22 ) and in foxes and seals in the United Kingdom, ( 23 ) and human infections have been observed in Russia ( 24 ). During the 2020–2021 epidemic, several reassortant viruses were detected in the Netherlands.…”

Influenza Viruses in Marine Mammals

“…In the United Kingdom, sporadic cases of IAV have been reported in seals, including subtypes A (H3N8) isolated from juvenile grey seals (Halichoerus grypus) in Cornwall in 2017 [34], and A (H5N8) from grey seals and two common seals (Phoca vitulina) in Norfolk in 2020 [35]. Due to the lack of routine surveillance of marine mammal populations in the UK impossible to determine whether these are random IV or endemic to the British seal population Highly pathogenic IAV (H5N8) was detected in lung samples of two gray seals stranded on the Baltic coast of Poland in 2016 and 2017.…”

“…[34], и A (H5N8) от серых тюленей и двух Phoca vitulina в Норфолке в 2020 г. [35]. Из-за отсутствия рутинного эпиднадзора за популяциями морских млекопитающих в Соединенном Королевстве невозможно определить, случайный ли ВГ птиц у этих видов, либо он проявляет эндемичность в популяции британских тюленей [36].…”