Sanhueza Teneo Daniel, Chesnais Cedric B, Manzano Javiera, Moll María Paz, Téllez Analía, Valenzuela-Nieto Guillermo
Instituto de Inmunología y Parasitología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5110566, Chile.
TransVIHMI, INSERM Unité, Institut de Recherche pour le Développement (IRD), Montpellier University, 34090 Montpellier, France.
Microorganisms. 2025 Jul 1;13(7):1549. doi: 10.3390/microorganisms13071549.
Waterborne gastrointestinal infections remain a global health concern, with approximately 1.7 billion diarrhea-related illnesses annually attributable to protozoan parasites. These pathogens are transmitted through contaminated water and exhibit high resistance to chlorination, posing substantial challenges to effective water treatment. This study focused on the most prevalent intestinal parasites in the Los Ríos Region of Chile: sp., , and . The objectives were to assess the prevalence of eukaryotic parasites in water samples-covering both drinking and recreational sources-to describe the circulating subtypes of sp. and to identify ecological factors associated with parasite presence. Water samples were analyzed using conventional PCR, next-generation sequencing (NGS) was employed for sp. subtype identification, and the environmental predictors were evaluated using a multivariable logistic regression model. A total of 132 water samples were analyzed, of which 15.2% were positive for sp. and 1.5% for , while no samples tested positive for . We identified subtypes ST1-ST4 of sp., along with ST7, ST10, ST14, ST21, and ST23-ST26, the latter being reported for the first time in Chile. Ecological factors significantly associated with sp. presence included higher water temperature and greater rainfall at positive sites. Potable water was associated with significantly lower odds of sp. infection (aOR = 0.04, 95% CI: 0.00-0.87; = 0.041), while precipitation increased infection odds by 3% per additional millimeter (aOR = 1.03, 95% CI: 1.00-1.06; = 0.036). Greater distance to the nearest farmhouse was also significantly associated with reduced infection risk, suggesting that proximity to livestock environments may influence sp. transmission. These findings help explain the high prevalence of sp. observed in humans in the Los Ríos Region and highlight the pivotal role of ecological conditions in driving waterborne transmission. To our knowledge, this is the first environmental study in Chile to clearly demonstrate the association between human infection, environmental factors, and the transmission dynamics of sp.
水源性胃肠道感染仍然是一个全球卫生问题，每年约有17亿例腹泻相关疾病可归因于原生动物寄生虫。这些病原体通过受污染的水传播，并且对氯化表现出高度抗性，给有效的水处理带来了巨大挑战。本研究聚焦于智利洛斯里奥斯地区最常见的肠道寄生虫： 种、 种和 种。目标是评估水样（包括饮用水源和娱乐用水源）中真核寄生虫的流行情况，描述 种的循环亚型，并确定与寄生虫存在相关的生态因素。使用常规PCR分析水样，采用下一代测序（NGS）鉴定 种的亚型，并使用多变量逻辑回归模型评估环境预测因子。共分析了132个水样，其中15.2%的水样 种呈阳性，1.5%的水样 种呈阳性，而没有水样 种呈阳性。我们鉴定出了 种的ST1 - ST4亚型，以及ST7、ST10、ST14、ST21和ST23 - ST26亚型，后者在智利首次报道。与 种存在显著相关的生态因素包括阳性位点水温较高和降雨量较大。饮用水与 种感染几率显著降低相关（调整后比值比[aOR]=0.04，95%置信区间[CI]：0.00 - 0.87；P = 0.041），而降水量每增加1毫米，感染几率增加3%（aOR = 1.03，95% CI：1.00 - 1.06；P = 0.036）。与最近农舍的距离更远也与感染风险降低显著相关，这表明靠近牲畜环境可能会影响 种的传播。这些发现有助于解释在洛斯里奥斯地区人类中观察到的 种的高流行率，并突出了生态条件在推动水源性传播中的关键作用。据我们所知，这是智利第一项明确证明人类感染、环境因素与 种传播动态之间关联的环境研究。
