Anterior kidney transcriptome responses. At six days post exposure, anterior kidney responses varied depending on host species in either the (A) up-regulated or (B) down-regulated gene lists. Consistently more genes were shared between chum and pink salmon than with Atlantic salmon, including up-regulation of hepcidin-1, prostaglandin E synthase 3 and down-regulation of antiviral response genes. (C) Most genes were identified with a main effect of infection (response independent of day post exposure). Genes responding with a time by infection interaction (response dependent on day) were mainly identified early in the response, at day three or six.