 Extremely serious. It starts with a slight fever, dryness of the throat. As the virus penetrates the red blood cells, the victim becomes dizzy. He gets to experience an itchy rash. From there, the poison goes to work on the central nervous system, causing severe muscle spasms, followed by the inevitable drooling. At this point, the entire digestive system collapses, accompanied by uncontrollable flatulence, until finally the poor bastard is reduced to a quivering, wasted piece of jelly.