Avian influenza in wild birds

Updated 10.04.2026

The Norwegian Veterinary Institute coordinates the surveillance of avian influenza in wild birds on behalf of the Norwegian Food Safety Authority. Highly pathogenic avian influenza was detected in Norway for the first time in 2020.

Avian influenza (AI) is monitored in wild birds and in poultry:

The surveillance programme for AI in wild birds aims to monitor the occurrence of avian influenza viruses of subtypes H5 and H7 in wild birds.

The surveillance programme for AI in poultry aims to document that Norwegian poultry flocks are free from influenza A viruses of subtypes H5 and H7.

Background

Avian influenza (AI) is cased by influenza A viruses. These viruses are highly contagious, extremely variable, and widely distributed among birds. Wild waterfowl, such as ducks, geese, swans, shorebirds and gulls, constitute a natural reservoir for various subtypes of low pathogenic avian influenza viruses. Virus-carrying wild birds normally do not develop clinical disease but shed large amounts of virus in their faeces.

In domestic poultry, infection with low and highly pathogenic avian influenza viruses can result in different disease outcomes. Most low pathogenic avian influenza viruses (LPAI viruses) cause little or no disease in poultry, but virus strains of the H5 and H7 subtypes may mutate and become highly pathogenic after becoming established in poultry flocks. Highly pathogenic avian influenza viruses (HPAI viruses) usually cause severe and highly contagious disease in poultry and captive birds. In some cases, mortality in poultry flocks may exceed 90%. All epizootics caused by HPAI viruses known so far have been due to influenza A subtypes H5 or H7.

Although avian influenza viruses are best adapted to birds, they can in some cases infect mammals, including humans, especially through close contact with infected birds.

2024

Influenza A virus was detected in 64 of 723 wild birds examined in the surveillance programme for avian influenza in Norway in 2024. Passive surveillance detected influenza A virus in 20 wild birds, of which 16 were identified as highly pathogenic avian influenza (HPAI) H5. Three of the HPAI detections in wild birds in 2024 were H5N1, twelve were H5N5, and one were H5Nx. Of 29 wild mammals tested as part of passive surveillance, one lynx, one oter, and two red foxes tested positive for HPAI H5N5. Active surveillance detected influenza A virus in 44 wild birds, of which one was characterised as H5Nx, and none were confirmed as HPAI.

Download report

Avian influenza in wildlife 2024 (pdf 1mb)

Previous reports

Avian influenza in wildlife 2023 (pdf 2mb)
Avian influenza in wild birds 2022 (pdf 2mb)
Avian influenza in wild birds 2021 (pdf 2mb)
Avian influenza in wild birds 2020 (pdf 758kb)
Avian influenza in wild birds 2019 (pdf 833kb)
Avian influenza in wild birds 2018 (pdf 2mb)
Avian influenza in wild birds 2017 (pdf 789kb)
Avian influenza in wild birds 2016 (pdf 2mb)
Avian influenza in wild birds 2010 (pdf 621kb)
Avian influenza in wild birds 2009 (pdf 465kb)
Avian influenza in wild birds 2007 (p. 115) (pdf 6mb)
Avian influenza in wild birds 2006 (p. 115) (pdf 3mb)
Avian influenza in wild birds 2005 (p. 109) (pdf 4mb)