Ocular toxoplasmosis in Latin American and European patients: clinical characteristics, visual outcomes, and recurrence patterns

BACKGROUND: Ocular toxoplasmosis is the most common cause of posterior uveitis worldwide and a major cause of visual impairment. Previous studies suggest that the disease may follow a more aggressive clinical course in patients from Latin America; however, direct comparative evidence between geographic populations remains limited. This study aimed to characterize the clinical, serological, and imaging features of a multiethnic cohort of patients with ocular toxoplasmosis and to assess differences according to geographic origin. METHODS: A retrospective chart review was performed including 144 patients diagnosed with ocular toxoplasmosis at a tertiary referral center in Barcelona, Spain. Clinical characteristics, recurrence patterns, visual outcomes, and serological findings were analyzed. Outcomes were compared between Latin American (n = 73) and European (n = 71) patients. RESULTS: Latin American origin (OR 8.21; p < 0.001) and older age at disease onset (OR 1.04; p = 0.009) were independently associated with atypical disease presentation. Latin American origin (β = +0.20 LogMAR; p = 0.02), congenital disease (β = +0.52 LogMAR; p < 0.001), and retinal zone I involvement (β = +0.57 LogMAR; p < 0.001) were independently associated with worse visual acuity outcomes. Latin American origin (OR 4.85; p = 0.002) and longer time since disease onset (OR 1.05; p = 0.04) were independently associated with multiple recurrences, whereas congenital disease (OR 0.03; p = 0.01) was associated with lower recurrence risk. Serum IgG levels were significantly higher in Latin American patients (p = 0.002), who also more frequently required systemic corticosteroids along with antiparasitic treatment. CONCLUSIONS: Patients of Latin American origin showed a higher prevalence of atypical disease, increased recurrence rates, and poorer visual outcomes compared with European patients. These findings support the hypothesis of a more severe disease phenotype in this population and highlight the importance of closer monitoring and individualized management strategies in patients at higher risk of severe ocular toxoplasmosis.