A common feature of many novel viral infections affecting humans or animals is their emergence from another animal species, which acts as a reservoir for the virus.
The first step in interspecies transmission of viruses is the availability of receptors recognised and bound by virus proteins to enter the host cells. Inside the cell, intrinsic factors can act as a further barrier to successful infection.
Understanding why some species – and individuals – are resistant to diseases, while others are devastated by them, gives us a powerful basis for developing new therapies.