In a macaque model of hemorrhagic smallpox, histopathologic tests at day 6 or 7 postexposure showed acute lymphohistiocytic myocarditis with myocardiocyte degeneration and hemorrhage, primarily driven by direct viral myocardial injury and mediated by CD14 monocytes, chemotactic cytokines, and interleukin 6 (12). Here, IL6 is linked to myocarditis.