News & Comment

The H5 subtype of highly pathogenic avian influenza viruses represents a significant challenge to animal and human health. H5 clade 2.3.4.4b viruses have experienced an unprecedented global spread, coupled with remarkable genetic plasticity for adaptation in birds and mammals. Although human infections remain very limited, the establishment in wild, marine, and farmed animals, including recently dairy cattle, is of concern. The role of mammalian hosts as intermediaries for zoonotic or even pandemic influenza A viruses should not be underestimated. In order to mitigate the zoonotic risk and be adequately prepared, it is essential to understand and monitor the dynamics of HPAIV H5 at the avian-mammal interface.

Acute viral infections are typically cleared by the host’s immune system, but certain RNA viruses can establish ‘within host’ persistent infections, for example in the central nervous system (CNS). Neurons within the CNS are a potential site for viral persistence due to the limited capacity of the host to deploy cytolytic and inflammatory defenses in this environment. Subacute sclerosing panencephalitis (SSPE) is a rare but fatal disease caused by persistent infection with measles virus (MeV), often occurring years after acute measles. Despite the availability of effective vaccines, SSPE remains a concern due to vaccine hesitancy and disruptions in vaccination programs.