OmniVira

Highly pathogenic avian influenza A (H5N1) virus infections in wild carnivores connected to mass mortalities of pheasants in Finland.

Niina Tammiranta1 Marja Isomursu2 Alice Fusaro3 Minna Nylund2 Tiina Nokireki4 Edoardo Giussani3 Bianca Zecchin3 Calogero Terregino3 Tuija Gadd4
Affiliations 4 institutions
  1. Finnish Food Authority, Animal Health Diagnostic Unit, Veterinary Virology, Mustialankatu 3, FI-00790 Helsinki, Finland. Electronic address: [email protected].
  2. Finnish Food Authority, Animal Health Diagnostic Unit, Wild Animal Pathology, Elektroniikkatie 3, FI-90590 Oulu, Finland.
  3. Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020 Legnaro, PD, Italy.
  4. Finnish Food Authority, Animal Health Diagnostic Unit, Veterinary Virology, Mustialankatu 3, FI-00790 Helsinki, Finland.
PMID36889484 DOI10.1016/j.meegid.2023.105423 Year2023 Journal Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases Infect Genet Evol Languageeng Statusppublish

Abstract

Highly pathogenic avian influenza (HPAI) has caused widespread mortality in both wild and domestic birds in Europe during 2020-2022. Virus types H5N8 and H5N1 have dominated the epidemic. Isolated spill-over infections in mammals started to emerge as the epidemic continued. In autumn 2021, HPAI H5N1 caused a series of mass mortality events in farmed and released pheasants (Phasianus colchicus) in a restricted area in southern Finland. Later, in the same area, an otter (Lutra lutra), two red foxes (Vulpes vulpes) and a lynx (Lynx lynx) were found moribund or dead and infected with H5N1 HPAI virus. Phylogenetically, H5N1 strains from pheasants and mammals clustered together. Molecular analyses of the four mammalian virus strains revealed mutations in the PB2 gene segment (PB2-E627K and PB2-D701N) that are known to facilitate viral replication in mammals. This study revealed that avian influenza cases in mammals were spatially and temporally connected with avian mass mortalities suggesting increased infection pressure from birds to mammals.

Supporting text Virus Host Location
Finland 3 Highly pathogenic avian influenza H5N1 2 Human 14 Mutation 222 Pheasant 1 Wild mammal 1 Galliformes 5 Influenza A virus 186 Influenza A Virus, H5N1 Subtype 300 Influenza in Birds 341 Lynx 7 Otters 3 Animals 1949 Finland 2 Foxes 17

Evidence records

5 total
Zoonotic Surveillance
2 records · 1 evidence types
Evidence type Viral Detection
2 records
OVE6821 Viral Detection
Key finding

H5N1 HPAI virus was detected in an otter, two red foxes, and a lynx found moribund or dead in southern Finland.

Virus
Influenza A virus H5N1
Host
Eurasian river otter Lutra lutra Natural host red fox Vulpes vulpes Natural host Eurasian lynx Lynx lynx Natural host
Location
Finland
Supporting text

Later, in the same area, an otter (Lutra lutra), two red foxes (Vulpes vulpes) and a lynx (Lynx lynx) were found moribund or dead and infected with H5N1 HPAI virus.

Method
virus detection
Sample type
moribund or dead animals
Geographic raw
southern Finland
Country inferred
FIN
OVE6822 Viral Detection
Key finding

HPAI H5N1 virus was detected during mass mortality events in farmed and released pheasants in southern Finland.

Virus
Influenza A virus H5N1
Host
ring-necked pheasant Phasianus colchicus Natural host
Location
Finland
Supporting text

In autumn 2021, HPAI H5N1 caused a series of mass mortality events in farmed and released pheasants (Phasianus colchicus) in a restricted area in southern Finland.

Method
virus detection
Sample type
farmed and released pheasants found dead
Geographic raw
southern Finland
Country inferred
FIN
Transmission Evidence
1 records · 1 evidence types
Evidence type Cross-species Transmission
1 records
OVE6825 Cross-species Transmission
Key finding

Highly pathogenic avian influenza A (H5N1) virus spilled over from infected pheasants to wild mammals in southern Finland.

Virus
Influenza A virus H5N1
Host
Lutrinae Natural host red fox Vulpes vulpes Natural host Lynx Natural host Phasianus Natural host
Location
Finland
Supporting text

In autumn 2021, HPAI H5N1 caused a series of mass mortality events in farmed and released pheasants (Phasianus colchicus) in a restricted area in southern Finland. Later, in the same area, an otter (Lutra lutra), two red foxes (Vulpes vulpes) and a lynx (Lynx lynx) were found moribund or dead and infected with H5N1 HPAI virus.

Method
spatial-temporal correlation | phylogenetic analysis | molecular analysis of PB2 mutations
Study design
ecological and phylogenetic field investigation
Transmission direction
animal-to-animal
Geographic raw
southern Finland
Functional Mechanism
1 records · 1 evidence types
Evidence type Molecular Adaptation
1 records
OVE6824 Molecular Adaptation
Key finding

H5N1 viruses from infected mammals in Finland carried PB2-E627K and PB2-D701N mutations that facilitate viral replication in mammals.

Virus
Influenza A virus H5N1
Host
Not specified
Location
Not specified
Supporting text

Molecular analyses of the four mammalian virus strains revealed mutations in the PB2 gene segment (PB2-E627K and PB2-D701N) that are known to facilitate viral replication in mammals.

Genes or proteins
PB2
Mutations
PB2-E627K | PB2-D701N
Mechanism types
replication adaptation
Genomic Evolution
1 records · 1 evidence types
Evidence type Phylogenetic Evolution
1 records
OVE6823 Phylogenetic Evolution
Key finding

Phylogenetic analysis showed that H5N1 strains from pheasants and infected mammals in Finland clustered together, indicating closely related viruses.

Virus
Influenza A virus H5N1
Host
Phasianus Natural host mammals Mammalia Natural host
Location
Not specified
Supporting text

Phylogenetically, H5N1 strains from pheasants and mammals clustered together.

Analysis methods
phylogenetic analysis