Avian influenza poses a risk to public health – improvements to health security needed at fur farms

According to current data, avian influenza has spread to 21 fur farms in Finland. The first results from whole-genome sequencing indicate wild birds, particularly the black-headed gull, to be the source of infection. 

This is reflected in the "rapid communication" article published in the Eurosurveillance journal by the Finnish Institute for Health and Welfare (THL) and the Finnish Food Authority. The article describes the avian influenza epidemic currently ongoing in fur farms in the Central and South Ostrobothnia regions of Finland. 

“In the case of the more widespread infections at individual farms, the possibility of intra-farm infections cannot be ruled out. Current conditions on fur farms that do not have effective measures in place to protect the animals from birds enable the spread of viruses from wild birds to farmed animals. Risk management would require measures from fur farms to prevent birds from coming into contact with fur animals," says Terhi Laaksonen, Director of Department at Finnish Food Authority.

Based on genetic investigations, some of the viruses found in fur animals had mutations which indicate that the virus has adapted as a result of mammalian infections. Viruses bearing mutations that enhance the replication of the virus in mammalian cells were found on two farms.  

It is important to monitor mutations related to pathogenicity, as avian influenza viruses mutate easily and mammalian adaptation could  increase their pathogenicity in humans as well.  

"The risk is particularly high with minks due to similarities between the respiratory tracts of minks and humans. Minks can also become infected with seasonal influenza by humans, which increases the risk of new viral variants to  emerge", says Erika Lindh, Senior Specialist at THL.

"The matter has wider than only national significance. International health authorities and scientists also recognise the worst-case scenario of mammalian adaptation leading to a pandemic caused by an influenza virus that is new to humans," says Otto Helve, Director of Department at THL.

The publication describes the epidemic situation, the factors affecting its emergence, and infection management measures taken by the authorities. 

Reference 

Highly pathogenic avian influenza A(H5N1) virus infection on multiple fur farms in the South and Central Ostrobothnia regions of Finland, July 2023. Lindh E., Lounela H., Ikonen N., Kantala T., Savolainen-Kopra C., Kauppinen A., Österlund P., Kareinen L., Katz A., Nokireki T., Jalava J., London L., Pitkäpaasi M., Vuolle J., Punto-Luoma AL., Kaarto R., Voutilainen L., Holopainen R., Kalin-Mänttäri L., Laaksonen T., Kiviranta H., Pennanen A., Helve O., Laamanen I., Melin M., Tammiranta N., Rimhanen-Finne R., Gadd T., Salminen M.. Euro Surveill. 2023;28(31):pii=2300400. https://doi.org/10.2807/1560-7917.ES.2023.28.31.2300400

Further information 

Avian influenza (Finnish Institute for Health and Welfare) (Link in Finnish)

Avian influenza (Finnish Food Authority) (Link in Finnish)
 

Erika Lindh 
Senior Researcher
Finnish Institute for Health and Welfare 
[email protected] 

Otto Helve 
Director of Department, Health Security 
Finnish Institute for Health and Welfare 
[email protected] 

Terhi Laaksonen 
Director of Animal Health and Welfare Department
Finnish Food Authority
[email protected]

Riikka Holopainen
Head of Animal Health Diagnostic Unit
Finnish Food Authority
[email protected]