Lim Rivka M, Lahoti Ruhi, Clark Jessica, Arinaitwe Moses, Anguajibi Victor, Alonso Sergi, Nankasi Andrina, Besigye Fred, Atuhaire Alon, Pedersen Amy B, Webster Joanne P, Lamberton Poppy H L
Institute of Evolution and Ecology, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom.
School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom.
PLoS Negl Trop Dis. 2025 Sep 3;19(9):e0012750. doi: 10.1371/journal.pntd.0012750. eCollection 2025 Sep.
Direct morbidity assessments are rarely included in monitoring and evaluation of Schistosoma mansoni mass drug administration programmes. This is despite morbidity reduction being the leading objective of control and elimination as a public health problem in the World Health Organization (WHO) targets. Instead, the number of eggs-per-gram (EPG) of faeces are used as a morbidity proxy. Furthermore, current WHO guidelines use infection intensity thresholds to determine where and when MDA is to be implemented. However, recent work has begun to question this assumption of a direct association between infection intensity in intestinal schistosomiasis and host morbidity. Here we aimed to examine the potential association between S. mansoni infection intensity and morbidity from pre-school-aged children (PSAC) through to elderly individuals, living in Bugoto, Uganda. Prevalence and intensities of S. mansoni infection were diagnosed by Kato-Katz and point-of-care circulating cathodic antigen tests (POC-CCAs) in 287 individuals aged 3-74 years, from Bugoto, Uganda. In addition to data on anaemia and self-reported symptoms, abdominal ultrasound examinations were conducted to identify liver parenchyma image pattern (IP), portal vein dilation (PVD) and left parasternal line (PSL) enlargement. Malaria status was determined using rapid diagnostic testing. Generalised additive models estimated associations between morbidity outcomes and infection intensity/presence, diagnostic method, co-infections, age and sex. The prevalence of positive IP scores, dilated PVD, enlarged PSL and anaemia were 9%, 34%, 33% and 13% respectively. Neither S. mansoni infection intensity or status were significantly associated with PVD, PSL, or anaemia. Age was the most consistent predictor of morbidity, with the highest burden of PVD, PSL and anaemia in PSAC. Malaria infection was also positively associated with PVD and anaemia. A positive POC-CCA predicted only self-reported blood in stool. Our findings add to growing evidence that current infection intensity is an inappropriate proxy for schistosomiasis morbidity, urging a revaluation of tools and targets. The observed prevalence of morbidities in PSAC evidence a need to elucidate the impact of less-specific morbidities, past S. mansoni and other parasitic infections on host health, and adds urgency to the on-going roll out of treatment to this age group.
在曼氏血吸虫群体药物给药项目的监测和评估中,很少纳入直接发病率评估。尽管将发病率降低作为世界卫生组织(WHO)控制和消除这一公共卫生问题的首要目标,但情况依然如此。相反,每克粪便中的虫卵数(EPG)被用作发病率的替代指标。此外,WHO当前的指南使用感染强度阈值来确定在何处以及何时实施群体药物给药(MDA)。然而,最近的研究开始质疑这种关于肠道血吸虫病感染强度与宿主发病率之间直接关联的假设。在此,我们旨在研究乌干达布戈托地区从学龄前儿童(PSAC)到老年人中曼氏血吸虫感染强度与发病率之间的潜在关联。通过加藤-卡茨法和即时检测循环阴极抗原试验(POC-CCA)对乌干达布戈托地区287名3至74岁个体的曼氏血吸虫感染率和感染强度进行诊断。除了贫血和自我报告症状的数据外,还进行了腹部超声检查以确定肝实质图像模式(IP)、门静脉扩张(PVD)和左胸骨旁线(PSL)增宽情况。使用快速诊断检测确定疟疾感染状况。广义相加模型估计发病率结果与感染强度/感染情况、诊断方法、合并感染、年龄和性别之间的关联。IP评分阳性、PVD扩张、PSL增宽和贫血的患病率分别为9%、34%、33%和13%。曼氏血吸虫感染强度或感染状况与PVD、PSL或贫血均无显著关联。年龄是发病率最一致的预测因素,PSAC中PVD、PSL和贫血的负担最高。疟疾感染也与PVD和贫血呈正相关。POC-CCA检测呈阳性仅能预测自我报告的粪便带血情况。我们的研究结果进一步证明,目前的感染强度不适用于作为血吸虫病发病率的替代指标,这促使人们重新评估相关工具和目标。PSAC中观察到的发病率表明,有必要阐明不太特异性的发病率、既往曼氏血吸虫感染和其他寄生虫感染对宿主健康的影响,并为向该年龄组持续推广治疗增添了紧迫性。