Department of Medical Parasitology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania.
National Neglected Tropical Diseases Control Programme, National Institute for Medical Research, 3 Barack Obama Drive, P.O. Box 9653, 11101, Dar-Es-Salaam, Tanzania.
Sci Rep. 2021 Jan 11;11(1):295. doi: 10.1038/s41598-020-80317-x.
Planning and implementation of schistosomiasis control activities requires an understanding of the prevalence, intensity of infection and geographical distribution of the disease in different epidemiological settings. Although, Tanzania is known to be highly endemic to schistosomiasis, there is paucity of data on the geographical distribution of schistosomiasis in potential large water bodies in the country. Thus, the present study was conducted to determine the prevalence, infection intensities and geographical distribution of schistosomiasis along villages located on the shoreline of Lake Nyasa, southern Tanzania. A cross-sectional study was conducted among 1560 children aged 1-13 years old living in villages located along the shoreline of Lake Nyasa. A single urine and stool sample was obtained from each participating child and screened for S. mansoni using Kato Katz (KK) technique to detect eggs and using point-of-care circulating Cathodic Antigen (POC-CCA) test to detect antigen in urine. Urine filtration technique was used to screen for S. haematobium eggs in urine samples. Villages/primary school were mapped using geographical information system and prevalence map was generated using ArcView GIS software. The overall prevalence of S. mansoni based on KK technique and POC-CCA test was 15.1% (95%CI: 13.4-16.9) and 21.8% (95%CI: 18.5-25.3) respectively. The prevalence S. haematobium was 0.83% (95%CI: 0.5-1.4) and that of haematuria was 0.9%. The arithmetic mean egg intensities for S. haematobium and S. mansoni were 18.5 mean eggs/10 ml (95%CI: 5.9-57.6) of urine and 34.7 mean epg (95%CI: 27.7-41.7) respectively. Villages located on the southern end of the lake had significantly high prevalence of S. mansoni than those located on the northern part (χ = 178.7838, P = 0.001). Cases of S. haematobium were detected only in three villages. Both S. mansoni and S. haematobium infections occur in villages located along the shoreline of Lake Nyasa at varying prevalence. These finding provide insights that can provide guidance in planning and implementation of MDA approach and other recommended measures such as improvement in sanitation, provision of clean water and behaviour changes through public health education.
尽管坦桑尼亚被认为是血吸虫病的高度流行地区，但关于该国大型潜在水体中血吸虫病的地理分布数据却很少。因此，本研究旨在确定坦桑尼亚南部尼亚萨湖（Lake Nyasa）沿岸村庄的血吸虫病流行率、感染强度和地理分布。在尼亚萨湖沿岸的 1560 名 1-13 岁儿童中进行了一项横断面研究。从每个参与的儿童中采集一份尿液和粪便样本，并用加藤厚涂片（Kato Katz，KK）技术检测粪便样本中的曼氏血吸虫卵，并用即时检测环卵沉淀抗原（POC-CCA）检测尿液中的抗原。用尿沉渣技术检测尿液样本中的埃及血吸虫卵。利用地理信息系统对村庄/小学进行绘图，并利用 ArcView GIS 软件生成流行率地图。根据 KK 技术和 POC-CCA 检测，曼氏血吸虫的总流行率分别为 15.1%（95%CI：13.4-16.9）和 21.8%（95%CI：18.5-25.3）。埃及血吸虫的流行率为 0.83%（95%CI：0.5-1.4），血尿率为 0.9%。埃及血吸虫和曼氏血吸虫的平均虫卵强度分别为 18.5 个/10ml 尿液（95%CI：5.9-57.6）和 34.7 个/epg（95%CI：27.7-41.7）。位于湖南端的村庄曼氏血吸虫流行率显著高于位于湖北端的村庄（χ2=178.7838，P=0.001）。仅在三个村庄检测到埃及血吸虫病例。尼亚萨湖沿岸的村庄存在不同流行率的曼氏血吸虫和埃及血吸虫感染。这些发现提供了有价值的信息，可以为规划和实施 MDA 方法以及其他推荐措施提供指导，如改善卫生条件、提供清洁水以及通过公共卫生教育改变行为。
