(1.1) ZIKV infected mature neurons in the frontal cortex and hippocampus in mice. (1.2) Infection caused microgliosis, the elevation of TNF-a, and upregulation of complement proteins (C1q and C3). (1.3) Infection caused hippocampal synaptic damage and memory impairment. (2) ZIKV infected mature neurons and replicated in adult human brain tissue. The gene discussed is C3; the disease is infection.