Seroprevalence of IgG Antibodies Against Toxoplasma gondii in HIV-Infected and Non-Infected Population in Iquitos, Peru

Toxoplasmosis is a cosmopolitan zoonosis that particularly threatens pregnant women and immunocompromised individuals. Among people living with HIV, Toxoplasma gondii may invade the central nervous system, producing neuropathological effects associated with mental and psychiatric disorders. We assessed the seroprevalence of anti–T. gondii IgG in HIV-infected and HIV-uninfected residents of Iquitos, Peru, and evaluated an in-house ELISA based on total lysed antigen (TLA) against a commercial kit. In this observational cross-sectional study, 151 participants were enrolled: 92 HIV-positive and 59 HIV-negative. Overall IgG seroprevalence was 88.08% (133/151), reaching 91.30% (84/92) in the HIV-positive group and 83.05% (49/59) in the HIV-negative group. Seroprevalence was highest among adults aged 36–60 years (89.33%; 67/75) and among males (89.77%; 79/88) versus females (85.71%; 54/63). Mean optical density values were greater in HIV-positive participants (1.37±0.393; 95% CI 1.28–1.45) than in HIV-negative participants (0.565±0.200; 95% CI 0.510–0.620), and were higher in men overall (1.18±0.502; 95% CI 1.07–1.30). These findings indicate very high exposure to T. gondii in Iquitos, with higher IgG prevalence and antibody levels in HIV-positive individuals. The marked OD difference suggests stronger IgG responses among HIV-positive participants, highlighting potential risk for toxoplasmic encephalitis. Serological screening and preventive counseling may be warranted in high-burden Amazonian communities.