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, their fetuses 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 lysate antigen (TLA) and recombinant GRA1 (rGRA1), with ELISA-TLA compared against a commercial kit. In this observational cross-sectional study, 151 participants were enrolled: 92 HIV-positive and 59 HIV-negative. ELISA-TLA showed a seroprevalence of 88.08% (133/151), reaching 91.30% (84/92) in the HIV-positive group and 83.05% (49/59) in the HIV-negative group. ELISA-rGRA1 showed a similar epidemiological pattern but lower overall seroprevalence, 81.46% (123/151), with 84.78% (78/92) in HIV-positive and 74.58% (44/59) in HIV-negative participants. Taken together, both TLA and rGRA1-based ELISAs showed similar epidemiological patterns, supporting the consistency of the serological findings. These results also indicate very high exposure to T. gondii in Iquitos, particularly among HIV-positive individuals, in whom prior exposure is clinically relevant because of the risk of reactivation under immunosuppression. Serological screening and preventive counseling may therefore be warranted in high-burden Amazonian communities.