Sputnik (virus)

Sputnik is virus, named after the Soviet Sputnik satellite, that is the first virus that has been found to have another virus as its host, making it ill. This raises new questions as to whether a virus is a living being - if it can die then it must have been alive.

Sputnik has the Mimivirus as its host. This quality makes Sputnik a virophage. As such, it exchanges genes with its host and consequently transfers them between Mimiviruses.

Sputnik was found in water tanks in Paris and the Mimivirus in water tanks in London. The Mimivirus is a rather strange virus that needs amoebas for reproduction, has an unusual large amount of genes and is so large that is was first thought to be a microbe ('mimi' stands for 'mimicking microbe'). Only when the English gave it to the French was it discovered not to be a microbe but a virus. The large amount of genes and their functions was the first hint that it might be considered to be a living being. The fact that it can be made ill was the second.

The Sputnik virus is thought to be one of a still largely unkown group of ocean viruses because 4 of its 21 genes have sequences that are frequently found in oceans. It is suspected that a lot of plankton is infected by the Mimi and possibly the Sputnik virus. Because of te importance of plankton in the carbon cycle, these viruses could also have an important influence on climate change.