Seven-days (acute) Chlamydia pneumoniae postinfection caused a 3.2-fold increase in ionized calcium-binding adaptor molecule 1 (IBA1)+ microgliosis and a 2.5-fold increase in glial fibrillary acidic protein (GFAP)+ astrogliosis in the hippocampi and cortices of infected versus uninfected AD+ mice (Fig. 3I, J; p < 0.05–0.01; extended data in Supplementary Fig. 9B–D), indicating amplified neuroinflammation due to infection. This evidence concerns the gene GFAP and Alzheimer disease.