A volcano plot (Fig. 4D) identified 32 metabolites showing 2-fold changes (FDR < 0.05), with 31 metabolites significantly increased (including S-Adenosylmethionine, Phosphoenolpyruvic acid, and Fructose-1,6-bisphosphatase 1) and 1 metabolite (Urocanic acid) significantly decreased in the encephalitis group compared to the meningitis group. The gene discussed is FBP1; the disease is infectious meningitis.