Ocular Involvement Following Postnatally Acquired Toxoplasma gondii Infection in Southern Brazil: A 28-Year Experience

PURPOSE: To determine the incidence of, and risk factors for, ocular involvement among people known to have postnatally acquired Toxoplasma gondii infection in a region of southern Brazil where there is a high prevalence of endemic disease. DESIGN: Retrospective longitudinal cohort study. METHODS: Records of 302 patients with serologic evidence of recent T gondii infection (a positive anti-T gondii IgM antibody test) from Erechim, Rio Grande do Sul state, Brazil (1974-2002) were analyzed. The incidence of ocular involvement was calculated in terms of person-years (PY) of follow-up. Risk factors for ocular involvement were analyzed using log-rank and Fisher exact tests. RESULTS: At initial ocular examination (baseline), 30 patients (9.9%) had intraocular inflammation only (anterior chamber cells and flare, vitreous inflammatory reactions, retinal whitening), without clinically apparent necrotizing retinochoroiditis. At baseline, men were more likely to have ocular involvement (P =.043) and antiparasitic treatment was associated with less ocular involvement (P =.015). Follow-up examinations were performed on 255 patients (median follow-up, 13.7 months [range 0.4-261.9 months]). Among those without ocular involvement at baseline, the incidence of necrotizing retinochoroiditis was 6.4/100 PY. Patients >40 years of age at first IgM test had a greater risk of incident necrotizing retinochoroiditis (hazard ratio = 4.47, 95% CI = 1.67-11.93, P =.003) than younger patients. The incidence of recurrent necrotizing retinochoroiditis was 10.5/100 PY. CONCLUSION: Isolated intraocular inflammatory reactions can be an initial manifestation of T gondii infection, with necrotizing retinochoroiditis occurring months or years later. Male sex and older age are risk factors for toxoplasmic retinochoroiditis. Antitoxoplasmic treatment may protect against early ocular involvement. (C) 2015 by Elsevier Inc. All rights reserved.