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Viruses are world champion parasites—think of all the trouble they give us, from Ebola to HIV. Now French researchers have discovered a viral first … a virus that infects another virus.

About the image: HIV virus infecting a cell

A virus that scientists are calling Sputnik was found in a newly discovered strain of so-called mimivirus, which is the world's largest known virus.

Virologist Jean-Michel Claverie, of France's National Center for Scientific Research and a team from the University of the Mediterranean in Marseille, happened upon the strain of mimivirus swimming in the water of a Parisian cooling tower. When they peeked inside the viral particle, they discovered Sputnik, which consists of only 21 genes.

They found that mimiviruses infected with Sputnik are less effective at infecting amoebae, which is what they normally do.

The researchers believe that Sputnik is the first of a yet-to-be-discovered family of viruses that they suspect may plague large viruses that attack ocean plankton. The French team reported their findings in the new issue of Nature, out yesterday.

The finding may answer a long-standing debate posed upon a 2004 cover of Scientific American: Are viruses alive?

Source: Scientific American
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