Understanding the appearance of new variants to better fight against avian flu

Highly pathogenic avian influenza viruses represent a threat to poultry farms, in which they cause significant mortality. Due to their zoonotic potential, they can also have an impact on human health.

Avian influenza is a family of viruses with many more or less pathogenic variants. Regularly, new variants are detected. To fight against this pathology, it is crucial to better understand how these new variants emerge. Highly pathogenic viruses can emerge from low pathogenic viruses by the introduction of basic amino acids at the hemagglutinin cleavage site. This new highly pathogenic virus appears in a host previously infected with a parent virus, weakly pathogenic.

A higher risk of new variants in chickens

Teams from the Host-Pathogen Interactions laboratory (IHAP – INRAE-ENVT) tested the hypothesis that interactions between a highly pathogenic variant and a weakly pathogenic variant could modulate the emergence of new highly pathogenic variants.

” In using and model experimental of co-infections in between a variant highly pathogenic and a variant weakly pathogenicnos works suggest what the viruses of the flu avian highly pathogens would be plus likely to emerge chez THE chickens what chez the Ducks “, underline Romain Volmerco-author of this study.

In fact, in chickens, it was observed that the low pathogenic H5N8 virus increased the replication and the appearance of pathological states of the highly pathogenic virus.

The opposite is observed in ducks. The presence of low pathogenic H5N8 reduces replication and the appearance of symptoms related to highly pathogenic H5N8. In contact with the low pathogenic virus, ducks set up a more powerful innate immune response than chickens, which allows inhibition of the highly pathogenic virus.

This research provides experimental evidence that highly pathogenic avian influenza virus may be more likely to emerge in chickens than in ducks. These results have important implications for preventing the emergence of highly pathogenic avian influenza viruses. This work also shows that interactions between viral variants within the host are important regulators of virus evolution.