Ministry of Health, Division of Vector Borne and Neglected Tropical Diseases, Nairobi, Kenya.
Oriole Global Health, Milton-Under-Wychwood, Great Britain.
PLoS Negl Trop Dis. 2023 Jan 5;17(1):e0011043. doi: 10.1371/journal.pntd.0011043. eCollection 2023 Jan.
Accurate mapping of schistosomiasis (SCH) and soil transmitted helminths (STH) is a prerequisite for effective implementation of the control and elimination interventions. A precision mapping protocol was developed and implemented in the coastal region of Kenya by applying the current World Health Organization (WHO) mapping guide at a much lower administrative level (ward).
A two-stage cluster survey design was undertaken, with 5 villages in each ward selected. From within each village 50 households were randomly selected, and a single child between the ages of 8 and 14 sampled following appropriate assent. The prevalence and intensity of infection of Schistosoma mansoni and STH were determined using the Kato-Katz method (single stool, duplicate slides) and urine filtration for S. haematobium.
Of the 27,850 school age children sampled, 6.9% were infected with at least one Schistosoma species, with S. haematobium being the most common 6.1% (95% CI: 3.1-11.9), and Tana River County having highest prevalence 19.6% (95% CI: 11.6-31.3). Prevalence of any STH infection was 5.8% (95% CI: 3.7-8.9), with Lamu County having the highest prevalence at 11.9% (95% CI: 10.0-14.1). The most prevalent STH species in the region was Trichuris trichiura at 3.1% (95% CI: 2.0-4.8). According to the WHO threshold for MDA implementation, 31 wards (in 15 sub-Counties) had a prevalence of ≥10% for SCH and thus qualify for annual MDA of all age groups from 2 years old. On the other hand, using the stricter Kenya BTS MDA threshold of ≥2%, 72 wards (in 17 sub-Counties) qualified for MDA and were targeted for treatment in 2021.
The precision mapping at the ward level demonstrated the variations of schistosomiasis prevalence and endemicity by ward even within the same sub-counties. The data collected will be utilized by the Kenyan Ministry of Health to improve targeting.
准确绘制血吸虫病（SCH）和土壤传播性蠕虫（STH）的分布图是有效实施控制和消除干预措施的前提。肯尼亚沿海地区采用当前世界卫生组织（WHO）的绘图指南，在更低的行政级别（病房）制定并实施了精准绘图方案。
采用两阶段聚类抽样设计，每个病房选择 5 个村庄。在每个村庄内，随机选择 50 户家庭，从每个家庭中抽取 1 名 8 至 14 岁的儿童进行采样。使用加藤厚涂片法（单份粪便，双份涂片）和尿沉渣过滤法检测曼氏血吸虫和 STH 的感染率和感染强度。
在所抽取的 27850 名学龄儿童中，有 6.9%的儿童至少感染了一种血吸虫，其中最常见的是埃及血吸虫，感染率为 6.1%（95%可信区间：3.1-11.9），且塔纳河县城的感染率最高，为 19.6%（95%可信区间：11.6-31.3）。任何 STH 感染的患病率为 5.8%（95%可信区间：3.7-8.9），其中拉穆县的感染率最高，为 11.9%（95%可信区间：10.0-14.1）。该地区最常见的 STH 物种是鞭虫，感染率为 3.1%（95%可信区间：2.0-4.8）。根据世界卫生组织实施 MDA 的阈值，有 31 个病房（在 15 个分区）的 SCH 患病率≥10%，因此符合从 2 岁开始对所有年龄段进行年度 MDA 的条件。另一方面，根据肯尼亚 BTS 更严格的 MDA 阈值≥2%，有 72 个病房（在 17 个分区）符合 MDA 条件，并在 2021 年进行了治疗。
在病房级别进行精准绘图，即使在同一分区内，也展示了血吸虫病患病率和流行程度的变化。收集的数据将由肯尼亚卫生部用于改善目标人群的定位。
