Severe Acute Respiratory Syndrome (SARS) is formed by a combination of mammalian and avian viruses, says a new study from the University of Toronto.The study, published in the January issue of the Journal of Virology, sheds light on the SARS coronavirus, a deadly form of pneumonia caused by the same viral family as the common cold. By tracing its evolutionary history, researchers theorize that SARS is likely the result of a rare recombination of viruses from both mammalian and avian hosts. This, they believe, forms an entirely new virus unrecognizable to human immune systems.
