Infectious diseases remain one of the leading causes of death worldwide despite innovations in medical research and the availability of new treatments. Emerging diseases include outbreaks of previously unknown diseases or known diseases where the incidence in humans has significantly increased in the past two decades. Detailed studies on emerging and re-emerging infectious agents to better understand pathogens’ biology and host pathogenesis are mostly lacking. The initial study protocol under this Task Order is to prepare for a rapid coordinated clinical investigation of acute infections of emerging and re-emerging infectious agents.