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Updated: Apr 16, 2026
3-D Imaging and Analysis of Neurons Infected In Vivo with Toxoplasma gondii
Published on: December 9, 2014
Ocular Involvement Following Postnatally Acquired Toxoplasma gondii Infection in Southern Brazil: A 28-Year
Tiago E F Arantes1, Claudio Silveira2, Gary N Holland3
1Ocular Inflammatory Disease Center, Stein Eye Institute, and the Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California; Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo, Brazil.
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.
