Upregulation of the proinflammatory cytokines IL6 (mediator of fever and acute inflammatory response) and IL8 (chemoattraction of neutrophils and macrophages) is consistently found in infected NHPs, with macrophages and plasmacytoid dendritic cells (pDCs) serving as the main sources of IL6 secretion in the spleen [12, 14, 193] . Primary human monocytes and macrophages produce both IL6 and IL8 after infection [200] . Elevated levels of IL6 have also been detected in MARV-infected mice [130] . Increased levels of IL1β mRNA and secreted protein were detected in primary human cells [200, 211] , but contradictory data have been reported for the NHP model. One study reported elevated IL1β levels in final disease stages [12] , whereas no change was observed in another study [14] .