A pathway seemingly ubiquitously upregulated after challenge with intracellular pathogens and parasites is interferon (IFN) signaling, with evidence of induction following challenge with rhinovirus (21), influenza A (22), Plasmodium falciparum (23), Plasmodium vivax (24), and Salmonella enterica serovar Typhi, particularly during periods of detectable bacteremia in typhoid fever (9). Here, IFNA1 is linked to typhoid fever.