Health authorities are investigating a fictitious disease, Fever B. The first case was observed in a 30-year old male. Marcus, who is an ecological scientist with routine occupational exposure to various areas in and around the Amazon River basin. Two months after returning from a 10-day trip to Bolivia, Marcus developed a high fever, a painful vesicular rash over about 30 percent of his body, and debilitating muscle aches and fatigue. He wasn't really himself until about 6 weeks after his early symptoms developed. He reported starting to feel weak and exhausted with mild aches about 2 days before the high fever and rash developed