Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
Department of Biomedical Science, Faculty of Public Health and Medical Science, Mettu University, Mettu, Ethiopia.
Infect Dis Poverty. 2019 Jan 10;8(1):1. doi: 10.1186/s40249-018-0513-5.
Schistosoma mansoni, causing intestinal schistosomiasis, is widely distributed in Ethiopia and new transmission foci are continually reported. Here we report new transmission sites and prevalence of S.mansoni infection among school children in Yachi areas, southwestern Ethiopia.
A cross-sectional survey was conducted among school children of Yachi Yisa and Yachi Efo elementary schools, southwestern Ethiopia, from April 2017 to June 2017. Three hundred seventeen school children aged six to 15 years were randomly selected to provide stool specimens for helminth infection examination by Kato-Katz and formol-ether concentration techniques. Snail survey was carried out to assess schistosome infection in Biomphalaria pfeifferi. Laboratory bred mice were also exposed to schistosome cercariae shed by B. pfeifferi en masse for definite identification of Schistosoma species.
From the 317 stool specimens examined using double Kato-Katz thick smear and single formol-ether concentration techniques, 224 (70.7%) were found positive for at least one intestinal helminth species. The most prevalent parasite was S. mansoni (42.9%) followed by Trichuris trichiura (34.1%) and Ascaris lumbricoides (14.2%). The prevalence of S. mansoni infection was significantly higher among the children attending Yachi Yisa School (49.4%) than those in Yachi Efo School (35.6%) (P = 0.002). The study also revealed that there was a significantly higher prevalence of S.mansoni infection among males (51.2%) than females (33.1%) (P < 0.001). However, the prevalence of S.mansoni infection was not significantly associated with age categories (P = 0.839). B. pfeifferi snails infected with schistosomes were collected from the water bodies found in the study area. After six weeks post exposure, adult S. mansoni worms were harvested from the mesenteric veins of laboratory bred mice.
The study revealed establishment of new S. mansoni transmission foci and moderate prevalence of schistosomiasis in Yachi areas. Hence, treatment of all school-age children once every two years is recommended. Snail control and non-specific control approaches including provision of clean water supply and health education should also complement mass drug administration of praziquantel.
曼氏血吸虫引起的肠道血吸虫病广泛分布于埃塞俄比亚，新的传播点不断报告。在这里，我们报告了埃塞俄比亚西南部亚奇地区新的传播地点和小学生中曼氏血吸虫感染的流行情况。
2017 年 4 月至 6 月，在埃塞俄比亚西南部的亚奇伊萨和亚奇埃福小学的小学生中进行了横断面调查。随机选择 317 名 6 至 15 岁的学生提供粪便样本，用加藤厚涂片和福尔马林乙醚浓缩技术进行寄生虫感染检查。进行钉螺调查以评估生物种群中曼氏血吸虫的感染。实验室饲养的老鼠也暴露于生物种群释放的血吸虫尾蚴中，以明确鉴定血吸虫种。
用双加藤厚涂片和单福尔马林乙醚浓缩技术检查的 317 份粪便标本中，有 224 份（70.7%）至少有一种肠道寄生虫阳性。最常见的寄生虫是曼氏血吸虫（42.9%），其次是鞭虫（34.1%）和蛔虫（14.2%）。在 Yachi Yisa 学校上学的儿童中，曼氏血吸虫感染的患病率（49.4%）明显高于在 Yachi Efo 学校上学的儿童（35.6%）（P=0.002）。研究还表明，男性（51.2%）的曼氏血吸虫感染率明显高于女性（33.1%）（P<0.001）。然而，曼氏血吸虫感染的流行率与年龄类别无关（P=0.839）。从研究区发现的水体中采集到感染血吸虫的生物种群。暴露 6 周后，从实验室饲养的老鼠的肠系膜静脉中收获成熟的曼氏血吸虫成虫。
该研究揭示了亚奇地区新的曼氏血吸虫传播点的建立和中等程度的血吸虫病流行。因此，建议每两年对所有学龄儿童进行一次治疗。还应控制钉螺并采取非特异性控制措施，包括提供清洁饮用水和开展健康教育，以补充吡喹酮的大规模药物治疗。
