A virus starts its infection by binding viral particles to the host’s surface cellular receptors. The recognition of cellular receptors is the first step towards viral entry into host cells, in addition to determining their tropism. The ability to engage receptors and the affinity of binding can define the efficiency of a virus when infecting an organism, while the amount of these receptors present in cells can indicate the intensity of infection. Viruses that have a high capacity to bind to more conserved receptors are more likely to migrate between different species, which may also reflect the susceptibility of hosts and increase viral pathogenicity (40, 41).