Paralleling trends in the CNS of these animals (32), we found that upstream enzymes (IDO1, KMO, and KYNU) displayed significant mRNA upregulation during at least one phase of infection (Figures 5A–C), while downstream enzymes (HAAO and QPRT) were either downregulated or unchanged (Figures 5D,E). The gene discussed is KYNU; the disease is infection.