Background and Aim: These three parks in North-east Thailand, Kosamphi Forest Park, Kumphawapi Monkey Garden, and Dong Ling Don Chao Pu Park, are internationally recognized for sheltering long-tailed macaques. Overfeeding by tourists and locals significantly increases the frequency of human-macaque encounters. Being close to each other raises the chances of contracting gastrointestinal (GI) parasites. This study was designed to estimate the prevalence and range of GI parasite infections in long-tailed macaques among the three major natural habitats. Materials and Methods: Three hundred fecal samples were collected from long-tailed macaques, with 100 samples from each of the three study sites. The samples underwent Formalin-ethyl acetate concentration technique examination. Parasites were identified based on their morphology and size as observed under a light microscope. Results: About 66.67% of the population had GI parasitic infection. Balantidium coli had the highest occurrence (41.66%), whereas Strongyloides spp. (24.33%), Trichuris spp. (18.33%), Entamoeba coli (10.33%), and Endolimax nana (2.33%) followed next in prevalence. A higher rate of single infections (41%) was reported compared to mixed infections (25.66%). At Dong Ling Don Chao Pu Park, the prevalence rate of B. coli in long-tailed macaques was 70%, markedly higher than those reported at the other two study sites. In these areas, the first known case of B. coli infection occurred in long-tailed macaques. In the Kumphawapi Monkey Garden, the prevalence of Strongyloides spp. and Trichuris spp. infections was significantly greater (45% and 28%, respectively) compared to the other two areas. Conclusion: In northeast Thailand, long-tailed macaques are predominantly infected with B. coli, causing GI protozoal infections. In this primate population of the region, Strongyloides and Trichuris species are common helminths. This study offers new knowledge on parasitic loads in Thai long-tailed macaques, essential for devising effective One Health approaches to prevent and manage zoonotic diseases. Keywords: Dong Ling Don Chao Pu Park, gastrointestinal parasite, Kosamphi Forest Park, Kumphawapi Monkey Garden, long-tailed macaques.

Trichostrongylus species are zoonotic gastrointestinal nematodes that occasionally infect humans, particularly in rural areas with close contact to livestock. However, the global prevalence of human trichostrongylosis remains uncertain. This systematic review and meta-analysis aimed to synthesize available prevalence data and describe regional and methodological differences in reported infections. Studies published between 2000 and 2025 reporting the prevalence of Trichostrongylus infections in humans (primarily T. colubriformis, T. axei, and T. orientalis) were searched in six databases (EMBASE, Ovid, PubMed, Scopus, Nursing & Allied Health Premium, and Web of Science) and Google Scholar. Pooled prevalence was estimated using a random-effects model. Subgroup analyses were conducted to assess prevalence by continent, country, population group, and diagnostic method. Thirty-seven studies from 14 countries, comprising 111,408 participants, were included. Most studies were conducted in Asia (23, 62.2%), particularly in Iran (12, 32.4%), and in Africa (12, 32.4%), mainly in Nigeria (5, 13.5%). The global pooled prevalence of Trichostrongylus infection was 1.2%. Prevalence was highest in Africa (1.7%), followed by South America (1.2%), Asia (1.0%), and Europe (0.8%). Subgroup analyses revealed substantial heterogeneity in prevalence across study populations, age groups, and detection methods (p < 0.05). Available evidence suggests that human Trichostrongylus infection remains a localized but persistent zoonotic concern in specific endemic regions, rather than a globally uniform problem. Diagnostic variability, limited regional coverage, and high heterogeneity highlight the need for standardized molecular diagnostics and broader surveillance to accurately define the global epidemiology of trichostrongylosis.

There is geographical variation in the morphology and genetics of Wuchereria bancrofti, the major cause of human lymphatic filariasis. This study aims to compare morphological and genetic variation of W. bancrofti microfilariae recovered from carriers in Lao PDR, Myanmar and Thailand. Six morphological parameters (body length, cephalic space length and width, length of head to nerve ring, body width at nerve ring, Innenkȍrper length and number of column nuclei between the cephalic space and nerve ring) were evaluated from microfilariae in Giemsa-stained thick blood films. A portion of the cytochrome c oxidase subunit 1 gene of mitochondrial DNA was sequenced and analysed. Wuchereria bancrofti microfilariae showed a wide variation in their morphology and morphometry among three countries. Phylogenetic analysis confirmed that all microfilariae belonged to W. bancrofti. Higher mutation frequencies were observed in samples from Myanmar, relative to Thailand and Lao PDR. This study highlights the morphological disparities of microfilariae and genetic variability within W. bancrofti among three geographical locations. We found that reported morphometric differences between localities were less clear-cut than previously thought. Further studies are needed to determine the microfilarial periodicity in Lao PDR.

This study aimed to molecularly identify Trichuris spp. in long-tailed macaques from two key habitats in Northeast Thailand: Dong Ling Don Chao Pu Park, Amnat Charoen Province, and Kumphawapi Monkey Garden, Udon Thani Province. Genomic DNA was extracted from 13 Trichuris spp. egg samples collected from 13 infected long-tailed macaques, and PCR amplification targeting partial sequences of the 18S rRNA gene and ITS2 region was performed for phylogenetic analysis. Of the 13 Trichuris spp. egg samples, the partial 18S rRNA gene was successfully amplified from six, while ITS2 amplification was unsuccessful. Phylogenetic analysis indicated that four specimens sequenced from Dong Ling Don Chao Pu Park were T. trichiura. In contrast, two specimens sequenced from Kumphawapi Monkey Garden clustered with the only confirmed T. ovis from goat, as well as unconfirmed Trichuris spp. from other ruminant hosts. These findings suggest that the Trichuris spp. in macaques are likely T. ovis; however, the evidence remains inconclusive. Therefore, accurate species identification in this region requires further molecular analysis using additional genetic markers. This study provides the first molecular identification of T. trichiura in long-tailed macaques from Northeast Thailand. Additionally, it is the first report suggesting the possible T. ovis infection in non-human primates. These findings highlight the potential for Trichuris spp. transmission across diverse host species, underscoring the need for enhanced surveillance of parasitic infections in wildlife and livestock, particularly in regions with close human-animal interactions. Continued molecular investigations are essential to elucidate Trichuris spp. transmission dynamics and zoonotic potential, aiding in public health risk mitigation.

Background: Enterobiasis, caused by Enterobius vermicularis, is recognized as a common intestinal helminthiasis worldwide. Despite multiple surveys in Thailand, no pooled synthesis at the country level has been carried out to evaluate prevalence patterns, temporal trends, or vulnerable groups. Therefore, this systematic review and meta-analysis were undertaken to provide an updated and comprehensive estimate of the prevalence of E. vermicularis in Thailand and to identify high-risk populations for targeted interventions. Methods: The systematic review and meta-analysis were conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO: CRD420251053217). Studies reporting E. vermicularis infection in Thailand were systematically searched in international and Thai databases. Pooled prevalence and odds ratios (ORs) were calculated using random-effects models. Subgroup analyses and meta-regression were performed according to year, region, age, population type, and diagnostic method. Results: A total of 56 studies, including 52,765 participants, were analyzed. The overall pooled prevalence was estimated at 3.6% (95% confidence interval [CI]: 2.1–5.9%), with a decline observed in the subgroup analysis by publication year, from 4.75% in 2000–2009 to 1.15% in 2020–2023. The highest prevalence was reported in Central Thailand (7.93%). High infection rates were found among immigrant children (25.2%), hilltribe children (19.9%), Karen students (15.5%), and children in orphanages (11.4%). A markedly higher prevalence was detected by the Scotch tape method compared with direct smear/concentration (12.9% vs. 0.33%). No significant difference in infection risk was observed between males and females (OR = 1.03, p = 0.65). Conclusions: The pooled prevalence of E. vermicularis in Thailand was estimated at 3.6%, but this figure should be interpreted with caution due to high heterogeneity across studies. More meaningful insights were identified in subgroup analyses, which revealed a temporal decline in prevalence, geographic clustering in Central Thailand, and disproportionately high infection rates among socioeconomically disadvantaged child populations. No statistically significant association was found between gender and risk of infection. These patterns underscore the need for targeted screening, deworming, and hygiene interventions, along with the standardized use of the Scotch tape technique for accurate surveillance and comparability of future studies.

Background/Objectives: Periductal fibrosis (PDF) is a common hepatobiliary abnormality associated with chronic Opisthorchis viverrini infection and may represent an ultrasonographic marker of chronic biliary injury in liver fluke-endemic regions. This systematic review and meta-analysis evaluated the association between ultrasound-defined PDF and cholangiocarcinoma (CCA)-related outcomes and summarized the prevalence of overall PDF and advanced periductal fibrosis (APF) in endemic populations. Methods: PubMed, Embase, and Scopus were searched from database inception to April 2026, supplemented by manual screening of reference lists. Observational studies reporting PDF prevalence and/or the association between PDF and CCA-related outcomes were included. Pooled odds ratios (ORs) and prevalence estimates were calculated using random-effects models. Five studies met the inclusion criteria. Results: Three studies involving 758,686 participants were included in the pooled association analysis. Ultrasound-defined PDF was associated with higher odds of CCA-related outcomes, including confirmed CCA, incident CCA, and clinically suspected CCA, with a pooled OR of 2.77 (95% CI: 2.24–3.44; I² = 0%). Because outcome definitions, effect measures, adjustment status, and PDF exposure categories varied across studies, this estimate should be interpreted as a summary association rather than as a precise estimate of confirmed CCA risk. Four studies involving 759,117 participants contributed to the overall PDF prevalence analysis, whereas three studies reported APF prevalence data. Prevalence estimates varied substantially across endemic settings, with extreme between-study heterogeneity. Conclusions: Overall, ultrasound-defined PDF may help identify individuals who warrant closer surveillance or further evaluation; however, it should not be interpreted as a definitive histopathological diagnosis or a proven causal precursor of CCA. Further prospective studies using standardized fibrosis definitions, blinded ultrasonographic assessment, confirmed or incident CCA outcomes, and adjustment for O. viverrini infection-related factors and other key confounders are needed to validate the role of PDF in CCA risk stratification.