Sleep Duration Identified as Risk Factor for Ocular Toxoplasmosis Recurrence

Researchers found that recurrence risk in patients with ocular toxoplasmosis remained relatively stable over the first five years, contrasting with prior studies that reported “a clustering of recurrences shortly after the initial episode and a decline over time.” This emphasizes the importance of long-term monitoring, they argue. Photo: Rami Aboumourad, OD. Click image to enlarge. Ocular toxoplasmosis— an infectious retinochoroiditis caused by the parasite Toxoplasma gondii—is the most common cause of infectious posterior uveitis worldwide. Recurrence rates are high, ranging from 40% to 79%, and reactivation has been reported more frequently in certain patient groups, such as young children and the elderly, pregnant and immunocompromised individuals and those treated with steroids without concurrent antibiotic therapy.To build on the existing literature, a new study published in Journal of Ophthalmic Inflammation and Infection sought to identify potential risk factors of disease recurrence. Its authors reported that patients who slept six to eight hours nightly had a lower likelihood of ocular toxoplasmosis recurrence, and women who became pregnant after diagnosis showed a threefold higher hazard of recurrence.Investigators reviewed records from a single university hospital in Italy between 1996 and 2023. Of 86 patients treated for an initial activation of ocular toxoplasmosis, 43 completed treatment and had at least 18 months’ follow‑up and were included in the analysis; all were immunocompetent and none received long‑term antibiotic prophylaxis. Thirty‑five of those 43 completed a questionnaire covering lifestyle and psychosocial factors. Treatments during acute episodes comprised either oral trimethoprim-sulfamethoxazole or pyrimethamine-sulfametopyrazine together with prednisone (50mg daily, tapered). The median follow‑up time was eight years, with the final recorded recurrence occurring nearly 11 years post-diagnosis.Nearly half of patients (49%) experienced at least one recurrence. The median time to first recurrence was just over six years. Kaplan-Meier cumulative probabilities for the first recurrence were 9.4% at one year, 16.9% at two years, 27.9% at three years and 57.9% at seven years. The overall incidence was roughly one recurrence per 10 person‑years across the cohort.Sleep duration was the only risk factor reaching statistical significance; specifically, patients who slept between six and eight hours had the lowest recurrence probability. Paradoxically, those sleeping more than eight hours per night showed higher recurrence rates.“Regular sleep patterns have been associated with a more resilient stress response and better regulation of inflammatory processes,” the researchers explained in their paper. “It is possible that individuals with adequate sleep are less susceptible to the immunological effects of stress, or are better able to cope with stressful events, which in turn may reduce the risk of toxoplasmosis reactivation.” At the same time, too much sleep can also have harmful effects, they noted, with previous studies demonstrating a link between excessively long sleep duration and chronic low-grade inflammation and metabolic dysregulation.Pregnancy after diagnosis was associated with a large estimated effect (hazard ratio: 3.1) but did not reach conventional significance, likely because only 15 women participated in the study. However, the authors pointed out that this finding does align with a previous retrospective analysis on 213 women of childbearing age, which “demonstrated a recurrence risk for toxoplasmic retinochoroiditis during pregnancy 7.4 times higher than during non-pregnancy periods.”Lesion location also showed a trend (zone 1 near the fovea had fewer recurrences than zone 2). No statistically significant differences in recurrence probability were found by gender, ethnicity, age, IgM status or by the two drug regimens. Trimethoprim use showed a modest, non‑significant trend toward better final visual acuity compared to pyrimethamine, but the difference was insignificant.Finally, the pattern of recurrences in this study varied from those reported previously. Prior work has described a concentration of recurrences soon after the initial episode, followed by a decline. In contrast, this study found that recurrence risk remained fairly constant over the first five years, with a cumulative incidence of about 9% at one year and 58% at seven years. According to the authors, “This suggests that the risk of recurrence persists over time and does not necessarily diminish with longer follow-up, highlighting the importance of sustained long-term monitoring and potential prophylactic strategies.”These results, the authors conclude, “could help identify individuals at higher risk of recurrence, and consequently, those who might benefit from secondary prophylaxis.”Click here for the journal source. Rizzo C, Micciolo R, Bacherini D, et al. Comparison of risk factors and different therapeutic options for ocular toxoplasmosis recurrence: a retrospective study. J Ophth Inflamm Infect. May 21, 2026. [Epub ahead of print].  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.