P-435. Prevalence and Risk Factors for Toxoplasma gondii Seropositivity in a Geographically Defined Cohort of Persons with HIV in Southern Alberta, Canada

Abstract Background New evidence suggests Toxoplasma gondii infection may have inflammatory and neurocognitive effects. Among people with HIV (PWH) with immunosuppression, T. gondii infection can reactivate causing significant morbidity. We aimed to identify the prevalence and risk factors for T. gondii infection among a geographically defined cohort of PWH.Figure 1:The proportion of Toxoplasma seropositive and seronegative tests among people with HIV at Southern Alberta Clinic Methods The Southern Alberta Clinic (SAC) provides centralized HIV care to all PWH in southern Alberta. SAC is linked with a comprehensive database that collects T. gondii serology (IgG) on entry into the cohort. Using this database, we evaluated temporal trends and risk factors for T. gondii infection between January 1st, 1985 and January 6th, 2022. We used Poisson regression models with robust variance to estimate unadjusted and adjusted prevalence ratios (aPR) with 95% confidence intervals (CI) for factors associated with T. gondii seropositivity (vs. seronegativity) among PWH.Figure 2:Toxoplasma seropositivity by country of birth among people with HIV at Southern Alberta Clinic from 1985-2022 Results Among 4,424 PWH receiving care at SAC between 1985-2022, 3,696 (84%) were T. gondii IgG negative and 728 (16%) T. gondii IgG positive at cohort entry. Over time, the prevalence of T. gondii infection has been increasing (Figure 1). In adjusted analyses, T. gondii seropositivity was associated with older age >50 years (vs. < 30 years) at serology testing (aPR: 1.7 [95% CI 1.2-2.5]) and birth outside of North America (vs. birth within North America), Central/South America (aPR: 4.5 [95% CI 2.9-6.7]), Sub-Saharan Africa (aPR: 4.3 [95% CI 2.8-6.5]), and Middle East/Northern Africa (aPR: 3.6 [95% CI 2.0-6.4]) (Figure 2). Conclusion We found an increasing prevalence of T. gondii infection among our population of PWH over time likely associated with a greater proportion of our population being both born outside of North America and age >50 years. Identifying the prevalence and risk factors for T. gondii seropositivity is important for monitoring potential negative outcomes associated with T. gondii infection and risk stratification among PWH. Disclosures All Authors: No reported disclosures