virophagehost

A virophage is a type of virus that infects other viruses. Specifically, virophages are viruses that parasitize giant viruses. These giant viruses, also known as mimiviruses or pandoraviruses, are themselves very large viruses that infect single-celled organisms like amoebas. When a virophage infects a host cell already infected by a giant virus, the virophage hijacks the replication machinery of the giant virus. This means the virophage uses the resources and machinery that the giant virus would have used to replicate itself. Consequently, the production of new giant virus particles is significantly reduced or completely inhibited. The virophage then replicates, using the giant virus's cellular machinery.

The discovery of virophages was unexpected and has expanded our understanding of viral diversity and interactions. It demonstrates a hierarchical parasitic relationship within the viral world, where one virus preys upon another. The first known virophage was discovered in 2008 and was named Sputnik virophage. It infects the Mimivirus, a type of giant virus that infects amoebas. Sputnik virophage appears to interfere with Mimivirus replication and also affects the host amoeba. Further research into virophages could reveal more about the complex ecological dynamics within microbial communities and the evolution of viruses.