Propelling Progeny

The capacity of a virus to disseminate through its host is a key determinant of virulence, but until recently, there was relatively little information on the molecular mechanisms used by viruses to accomplish this. On page 873 of this issue, Doceul et al. (1) propose that poxviruses spread within a host by inducing infected cells to propel progeny virions along their cell surfaces, and across those of neighboring newly infected cells, until they reach the surfaces of uninfected cells.