The equine influenza virus from the ongoing outbreak has been further characterized


<div>The samples from the respiratory tract of horses that were analysed at Evira on 4 December have been identified as equine influenza A2, H3N8 virus, a member of the variant-American lineage.</div>

The equine influenza viruses are divided into subtypes A1 and A2

In the last years, epidemics caused by the subtype A1 have not been identified around the world. Instead, equine influenza outbreaks caused by the A2 virus have been reported in for example Sweden, Denmark, France and Great Britain. In these, the virus of the American lineage was identified. In Great Britain, a so-called European virus variant was isolated in 2005 from one disease outbreak.

In general, outbreaks have occurred in unvaccinated or inadequately vaccinated horses

In some cases even horses that were vaccinated in accordance with the recommendations have fallen ill, but then the symptoms have generally been mild.
It is important that all of the horses on the farm are vaccinated in order to reach sufficient herd immunity. All of the equine influenza vaccines on the Finnish market contain antigens from viruses similar to strains circulating in the field and manufacturers update their products when the viral strains change.

The spread of equine influenza is prevented by vaccination

The best protection is gained by vaccinating the whole horse population (e.g. the whole stable). The protection against equine influenza achieved by vaccination is short term, which means that in order to maintain sufficient protection the horses should be vaccinated regularly from the age of six months with one year intervals, and in the case of an epidemic even at three-month intervals. We also have to remember that a vaccinated horse can still spread the disease, even if it doesn’t fall ill itself.

Equine influenza is not transmittable to humans.

For more information, please contact:
Senior Researcher Christine Ek-Kommonen, Veterinary Virology Research Unit,
tel. +358 50 514 3926, christine.ek-kommonen
Senior Researcher Anita Huovilainen, Veterinary Virology Research Unit (viral analysis), tel. +358 50 544 1981, anita.huovilainen
Veterinary Officer Karoliina Alm-Packalén, Animal Virology Research Unit (vaccinations), tel. +358 40 486 0052, karoliina.alm-packalen

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