Prevalence of Soil-Transmitted Helminths in Long-Tailed Macaques (Macaca fascicularis) in Asia: A Systematic Review...

Long-tailed macaques (Macaca fascicularis) commonly inhabit human-modified environments across Asia, where close human-macaque interactions have increased interest in understanding soil-transmitted helminth (STH) infections at human-wildlife interfaces. Because gastrointestinal helminth infections can affect animal health, understanding STH prevalence may support wildlife health surveillance. This systematic review and meta-analysis aimed to estimate the prevalence of major STHs in long-tailed macaques across diverse habitat settings in Asia. EMBASE, PubMed, and Scopus were systematically searched for studies published between 2000 and January 2026, with additional records identified through Google Scholar. Random-effects models with Freeman-Tukey double-arcsine transformation were used to calculate pooled prevalence estimates, and subgroup analyses were performed by habitat type, country, and diagnostic method. Thirty-five studies comprising 5505 macaques from seven countries, predominantly in Southeast Asia, were included. Studies involved urban/temple-associated free-ranging, wild/semi-wild, and captive populations. Among free-ranging macaques, pooled prevalence estimates were 19.3% for Strongyloides spp., 12.9% for hookworms, 9.1% for Trichuris spp., and 3.3% for Ascaris spp. In captive macaque populations, pooled prevalence estimates were 3.6% for Strongyloides spp., 2.2% for hookworm, 1.4% for Ascaris spp., and 8.2% for Trichuris spp. Subgroup analyses by habitat type suggested relatively higher prevalence estimates in urban/temple-associated settings than in wild/semi-wild habitats for several STH taxa. However, substantial between-study heterogeneity (I² > 90% in most analyses), publication bias, and possible small-study effects were identified in some analyses, particularly for hookworm prevalence estimates. These findings indicate that STH infections have been documented among long-tailed macaque populations across diverse habitat settings in Asia. Nevertheless, pooled prevalence estimates should be interpreted cautiously because of substantial heterogeneity, diagnostic variability, and possible publication bias. Future standardized surveillance and molecular investigations may support improved understanding of the prevalence and distribution of STH infections at human-wildlife interfaces.