Protective and curative effects of rifampicin in Acanthamoeba meningitis of the mouse. BALB/c mice inoculated nasally with Acanthamoeba culbertsoni, resulting in amebic encephalitis and death 3-7 days, were treated with rifampicin prophylactically (daily for 2 days with 75 and 100 mg/kg) and after infection (daily for 5 days with doses of 10-100 mg/kg). Prophylactic treatment resulted in full protection against infection, as assessed by absence of symptoms of central nervous system malfunction and negative brain culture 10 days after inoculation. Curative treatment was effective at the same doses; however, at doses of 10, 25, and 50 mg/kg, only two of six animals were free of symptoms and infection. 