IL6 and infection: We previously reported that YFV infection of mice resulted in rapid and transient induction of high levels of the proinflammatory cytokines IL-6 and MCP-1 in serum [30], consistent with human studies of YF [22], YF vaccine-associated viscerotropic disease [37] and NHP infection with the wild type Asibi virus [IL-6 only, [38]].