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Close relationship between mink influenza (H10N4) and concomitantly circulating avian influenza viruses
M Berg1, L Englund, I A Abusugra
1Department of Veterinary Microbiology, Swedish University of Agricultural Sciences, Biomedicum, Uppsala.
Abstract:
Strains of an influenza H10N4 virus have been isolated during an outbreak of a respiratory disease in mink on the south-east coast of Sweden. This was the first example of a disease in mammals caused by the H10 subtype. We compared the A/mink/Sweden/84 strain with two recent avian H10N4 isolates, one from fowl and another from a mallard, both isolated in Great Britain in 1985 as well as the prototype A/chicken/Germany/N/49 (H10N7). The comparison was carried out by genomic analysis of the strains by oligonucleotide fingerprinting and in bioassays on mink. The oligonucleotide fingerprint analysis revealed a high degree of genomic homology of around 98% between the viruses from mink, mallard and fowl. Only the recent avian isolates, that from the mallard and fowl could infect mink by contact, causing similar pathological and clinical signs and inducing seroconversion as did the mink virus. However, the susceptibility of mink to the fowl and mallard viruses by contact was less pronounced than that to the mink virus. Both the genomic homology and the similarities from the infectivity and pathogenicity studies between the mink virus and the recent avian isolates point to a direct invasion of the mink population by an avian H10N4 virus.
Insights
Avian influenza H10N4 virus caused a mink respiratory disease outbreak. Genomic and bioassay data suggest a direct avian-to-mink transmission of this H10 subtype virus.
Area of Science:
- Virology
- Mammalian Disease Outbreaks
Background:
- Influenza H10N4 virus caused a respiratory disease outbreak in mink.
- This marked the first documented mammalian disease caused by the H10 influenza subtype.
Purpose of the Study:
- To compare the A/mink/Sweden/84 strain with avian H10N4 isolates.
- To investigate the genomic relationship and pathogenicity of these strains in mink.
Main Methods:
- Oligonucleotide fingerprinting for genomic analysis.
- Bioassays on mink to assess infectivity and pathogenicity.
Main Results:
- High genomic homology (~98%) found between mink, mallard, and fowl H10N4 viruses.
- Avian isolates infected mink via contact, causing similar disease signs and seroconversion, though less pronounced than the mink virus.
- Mink virus showed higher susceptibility in mink compared to avian isolates.
Conclusions:
- Genomic and pathogenicity data strongly suggest direct avian-to-mink transmission of an H10N4 influenza virus.
- The findings highlight the potential for avian influenza viruses to jump to mammalian hosts.