Virus structures constrain transmission modes

Here we investigate links between the structures of viruses and routes of transmission. Viruses show a wide range of different structures, and the transmission of viruses between vertebrate hosts can take place through many different routes. We compiled a database of 243 virus–host combinations and report a statistical analysis that documents the associations between structures and routes of transmission—for example, viruses that are transmitted by the faecal–oral mode of infection are rarely enclosed in a lipid envelope.