Infections often present as acute clinical events; thus, it is important to capture dynamic changes in transcript abundance that occur during the course of the infection from the time of initial exposure. Blood signatures have been described in the context of acute infections caused by a wide range of pathogenic parasites, viruses and bacteria, including Plasmodium [79, 80] , respiratory viruses (infl uenza, rhinovirus, respiratory syncytial virus) [13, [81] [82] [83] [84] , dengue virus [85, 86] , and adenovirus [82] , as well as Salmonella [87] , Mycobacterium tuberculosis [78] , Staphylococcus aureus [88] , Burkholderia pseudomallei [76] and the general context of bacterial sepsis [77, [89] [90] [91] . Some of those pathogens will persist and establish chronic infections (for example, human immuno deficiency virus and Plasmodium) that may lead to a state of latency (for example, tuberculosis), and transcript profi ling may be used in those situations as a surveillance tool for monitoring disease progression or reactivation.