Klohe Katharina, Koudou Benjamin G, Fenwick Alan, Fleming Fiona, Garba Amadou, Gouvras Anouk, Harding-Esch Emma M, Knopp Stefanie, Molyneux David, D'Souza Susan, Utzinger Jürg, Vounatsou Penelope, Waltz Johannes, Zhang Yaobi, Rollinson David
Global Schistosomiasis Alliance, London, United Kingdom.
Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.
PLoS Negl Trop Dis. 2021 Feb 25;15(2):e0008995. doi: 10.1371/journal.pntd.0008995. eCollection 2021 Feb.
Schistosomiasis is a parasitic disease caused by trematode worms of the genus Schistosoma and belongs to the neglected tropical diseases. The disease has been reported in 78 countries, with around 290.8 million people in need of treatment in 2018. Schistosomiasis is predominantly considered a rural disease with a subsequent focus of research and control activities in rural settings. Over the past decades, occurrence and even expansion of schistosomiasis foci in peri-urban and urban settings have increasingly been observed. Rural-urban migration in low- and middle-income countries and subsequent rapid and unplanned urbanization are thought to explain these observations. Fifty-five percent (55%) of the world population is already estimated to live in urban areas, with a projected increase to 68% by 2050. In light of rapid urbanization and the efforts to control morbidity and ultimately achieve elimination of schistosomiasis, it is important to deepen our understanding of the occurrence, prevalence, and transmission of schistosomiasis in urban and peri-urban settings. A systematic literature review looking at urban and peri-urban schistosomiasis was therefore carried out as a first step to address the research and mapping gap.
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic computer-aided literature review was carried out using PubMed, ScienceDirect, and the World Health Organization Database in November 2019, which was updated in March 2020. Only papers for which at least the abstract was available in English were used. Relevant publications were screened, duplicates were removed, guidelines for eligibility were applied, and eligible studies were reviewed. Studies looking at human Schistosoma infections, prevalence, and intensity of infection in urban and peri-urban settings were included as well as those focusing on the intermediate host snails.
A total of 248 publications met the inclusion criteria. The selected studies confirm that schistosomiasis is prevalent in peri-urban and urban areas in the countries assessed. Earlier studies report higher prevalence levels in urban settings compared to data extracted from more recent publications, yet the challenge of migration, rapid uncontrolled urbanization, and resulting poor living conditions highlight the potential for continuous or even newly established transmission to take place.
The review indicates that schistosomiasis has long existed in urban and peri-urban areas and remains a public health problem. There is, however, a challenge of comparability of settings due to the lack of a clear definition of what constitutes urban and peri-urban. There is a pressing need for improved monitoring of schistosomiasis in urban communities and consideration of treatment strategies.
血吸虫病是一种由血吸虫属吸虫引起的寄生虫病，属于被忽视的热带病。该病已在78个国家有报告，2018年约有2.908亿人需要治疗。血吸虫病主要被视为一种农村疾病，随后研究和防治活动的重点也在农村地区。在过去几十年中，越来越多地观察到血吸虫病疫源地在城市周边和城市地区的出现甚至扩大。低收入和中等收入国家的农村向城市移民以及随后快速且无规划的城市化被认为可以解释这些现象。据估计，全球55%的人口已生活在城市地区，预计到2050年这一比例将增至68%。鉴于快速城市化以及控制发病率并最终实现消除血吸虫病的努力，加深我们对城市和城市周边地区血吸虫病的发生、流行和传播的理解非常重要。因此，作为填补研究和绘图空白的第一步，开展了一项关于城市和城市周边血吸虫病的系统文献综述。
按照系统评价和荟萃分析的首选报告项目（PRISMA）指南，于2019年11月利用PubMed、ScienceDirect和世界卫生组织数据库进行了系统的计算机辅助文献综述，并于2020年3月更新。仅使用至少有英文摘要的论文。对相关出版物进行筛选，去除重复项，应用纳入标准指南，并对符合条件的研究进行审查。纳入研究城市和城市周边地区人类血吸虫感染、感染率和感染强度的研究以及关注中间宿主螺类的研究。
共有248篇出版物符合纳入标准。所选研究证实，在评估的国家中，血吸虫病在城市周边和城市地区普遍存在。早期研究报告的城市患病率高于从最新出版物中提取的数据，但移民、快速无控制的城市化以及由此导致的恶劣生活条件所带来的挑战凸显了持续甚至新传播发生的可能性。
该综述表明，血吸虫病在城市和城市周边地区长期存在，仍然是一个公共卫生问题。然而，由于缺乏对城市和城市周边地区构成的明确定义，存在环境可比性的挑战。迫切需要加强对城市社区血吸虫病的监测并考虑治疗策略。
