Unfit viruses cause worse disease

The strains of **HIV** that produce most **progeny** might not be the ones that cause AIDS. According to a new **computer model**, HIV must evolve to actually become less productive before it causes disease. The model predicts that, for AIDS to develop, viral strains that kill **host cells** quickly must drive out those that spend a long time in the host cell just churning out copies of themselves. The prevailing wisdom is that slow-killing, highly productive viruses will predominate in a patient. But Dominik Wodarz of the University of California in Irvine and his colleague David N. Levy at New York University challenge this wisdom by considering a newly discovered and controversial property of HIV called co-infection, where more than one strain of HIV can infect the cells of the **immune system**.... "Zdroj":[ http://www.nature.com/news/2007/070730/full/070730-5.html]

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