High risk of developing toxoplasmic encephalitis in AIDS patients seropositive to Toxoplasma gondii.

We studied 41 AIDS patients in the Austrian Tyrol with respect to toxoplasma antibody titers and the presence of CNS toxoplasmosis. In no patient had primary Pneumocystis carinii pneumonia (PcP) prophylaxis with either trimethoprim/sulfamethoxazole or pyrimethamine/sulfadoxine been applied; the degree to which CNS toxoplasmosis is influenced by this kind of PcP chemoprophylaxis, widely used elsewhere, is still unclear. In this study 47.4% of toxoplasma-seropositive patients developed CNS toxoplasmosis, compared to the previously estimated risk of 12%-28% for developing CNS involvement in such patients. In view of the high risk of toxoplasma-seropositive patients with AIDS, increased efforts in developing a well-tolerated chemoprophylaxis to combat CNS toxoplasmosis are required.