With single-minded purpose, hundreds of viruses latch onto the walls of host cells. Vehemently, wriggling, they use the highly tangled shepherd's crook, at one end to gain access to the cells. As the wall of the host cell contracts, it closes around the virus and engulfs it.Once this viral intruder has gained access, it sets to work, with the lethal intensity of an armed robber. Quickly it sheds the outer coating of protein, exposing the lethal core...