Global prevalence and associated factors of intestinal parasitic infections among institutionalized populations: a systematic review and meta-analysis

Background: Various studies have been conducted on intestinal parasitic infections among different institutionalized populations with varying outcomes. We aimed at conducting a systematic review and meta-analysis on the prevalence and associated factors of intestinal parasitic infections (IPIs) among institutionalized populations. Methods: Articles published from January 2000 to October 2025 were retrieved from online sources such as Medline/ PubMed, Google Scholar and Scopus. Two authors (AAY and EA) independently extracted and reviewed all relevant data using a standardized Microsoft Excel data extraction form. Funnel plots and Egger’s tests were used to assess publication bias, followed by trim-and-fill analysis. A p-value < 0.05 indicates statistical significance. The pooled estimates and associated factors were assessed with a random-effects model using Stata/ SE version 17.0. Results: The pooled sample size for the study was 35,716 drawn from 59 journal articles. These articles included 21 (35.6%) from refugees, 17 (28.8%) from prison inmates, 13 (22.0%) mentally retarded institutions, 3 (5.1%) elderly nursing homes, 2 (3.4%) rehabilitation centers, 1 (1.7%) long-term care facilities and 2 (3.4%) military camps. The overall prevalence of IPIs among institutionalized populations was found to be 34.0% (95% CI: 29.0%, 39.0%). Based on type of institution, rehabilitation centers had the highest prevalence of IPIs with 57.0% (95% CI: 39.0%, 76.0%). Additionally, based on continent, Australia presented with the highest prevalence of IPIs with 65.8% (95% CI: 57.2, 74.4). Again, this review found Blastocystis hominis as the most prevalent protozoan prevalent among institutionalized populations at 18.6% (95% CI: 13.2–24.1), and Ascaris lumbricoides as the most prevalent helminth 5.0% (95% CI: 3.9–6.1). Studies from mentally retarded institutions and prisons showed that trimmed fingernails were associated with reduced odds of IPIs (pooled OR: 0.53, 95%CI: 0.40–3.44, p < 0.010). Conclusion: The pooled prevalence showed the presence of IPIs in about a third (34%) of institutionalized populations, presenting a major public health concern. Additionally, untrimmed fingernails in various institutions seemed to predispose participants to IPIs. It is therefore recommended that health professionals conduct periodic screening and treatment for IPIs. Lastly, institutional leaders, particularly those of psychiatric and prisons facilities should consider offering nail care services to control the transmission of IPIs.