Transcriptional signatures evident during the acute phase of babesiosis were cytokines and chemokines, such as IL-0, TNF, IL-1B, IL-18, CSF1, CXCL10 and CXCL16; pattern recognition receptors, such as CD14, TLR and NOD2; complement components, such as C1R, C2, C3aR1, CFB, CFI and CFP; cell adhesion molecules, such as ICAM1/2 and SELL; and apoptosis markers, such as CASP, BAX and BAK. Here, C3AR1 is linked to babesiosis.