SEA-CHANGE. “A sea-change in how we define viral infection is being driven by a combination of classical genetics and the genomic revolution. In this emerging view, the well-known role of host genetic variation comes to the fore because highly specific allelic polymorphisms or mutations predispose a limited number of individuals to diseases caused by viruses that otherwise only rarely cause overt disease. In a real sense, the genes in the host “cause” the disease, as the viruses can infect many but cause disease in only a few.”
http://www.sciencedirect.com/science/article/pii/S0092867409007831