Biology subjects
Publications and source records attributed to Terrey, J..
We detected H5N1 high pathogenicity avian influenza in captive Greater Rhea (Rhea americana). Viral genetic analysis revealed the mammalian associated PB2-E627K mutation, indicating selection of mammalian-relevant mutations in ratites. Pathologic investigation of available tissues demonstrated severe multifocal necrotising inflammation, and a strong vasculotropism.
H5Nx clade 2.3.4.4b high pathogenicity avian influenza viruses (HPAIV) have been detected repeatedly in Great Britain (GB) since autumn 2020, with H5N1 dominating detections but with low level detection of H5N5 during 2025. Globally, these viruses have caused mass mortalities in captive and wild avian and mammalian populations, including terrestrial and marine mammals. H5N1 has been the dominant subtype, and whilst incursions have overlapped temporally, occurrences have often been spatially distinct. Here, we report the detection of a mortality event in wild birds on the Norfolk coastline in the east of England, where H5N1 HPAIV was detected in five Great Black-backed Gulls (Larus marinus) and a Northern Fulmar (Fulmarus glacialis). Interestingly, at the same site, and as part of the same mortality event, a total of 17 Great Black-backed Gulls, one Herring Gull (Larus argentatus), one Atlantic Puffin (Fratercula arctica) and one Northern Fulmar tested positive for H5N5 HPAIV. Additionally, H5N5 was also detected in 17 co-located Grey Seal carcases (Halichoerus grypus). The H5N1 HPAIV from an infected bird belonged to genotype DI.2, closely related to contemporaneous detections in GB wild birds and poultry. In contrast, all H5N5 HPAIVs from birds and seals were genotype I with a 22-amino acid stalk deletion in NA and the 627K polymorphism in PB2. This represents the first recorded instance in GB of two subtypes being detected within the same avian population at the same location. It is also the first mass detection of HPAIV H5N5 in mammals within GB. Potential infection mechanisms are discussed.
Clade 2.3.4.4b H5N1 high pathogenicity avian influenza virus (HPAIV) continues to pose a significant global threat, affecting wild and domestic avian populations, and mammalian species. In early 2024, H5N1 HPAIV was detected in dairy cattle in the United States of America, where it has continued to circulate, with sporadic detections also reported in other ruminant species. The detection of high viral loads in milk from infected cattle, has resulted in several human infections, underscoring the zoonotic potential of these viruses. In response, several countries have intensified surveillance in non-avian species to evaluate the potential for undetected viral circulation in captive mammals. In Great Britain, bulk milk tank testing of cattle and targeted surveillance of captive mammalian species on an infected premises is undertaken in accordance with the outcome of a rapid risk assessment undertaken to determine the epidemiological links between the poultry and captive mammals. A result of this testing was the first recorded detection of clade 2.3.4.4b H5N1 HPAIV in a sheep in March 2025, identified on an infected poultry premises in Great Britain. An initial seropositive result in a single ewe triggered further investigation, confirming serological positivity across repeated sampling and the presence of viral RNA in milk samples. This detection was confined to a single animal and was likely attributable to proximity to infected poultry and a presumed heavily contaminated environment. The implications of this ruminant detection are discussed in the context of interspecies transmission and surveillance strategies.