Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, UK; Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.
Acta Trop. 2013 Nov;128(2):234-40. doi: 10.1016/j.actatropica.2013.01.003. Epub 2013 Jan 11.
Urogenital schistosomiasis is an important public health issue in Zanzibar. Transmission of the parasite to the human population is related to the distribution of the intermediate snail host, Bulinus globosus. We measured B. globosus abundance and Schistosoma haematobium prevalence within snails in a series of naturally occurring populations and compared prevalence detected by observing cercarial shedding for patent infections, and by PCR using DraI repeat. A total of 2146 B. globosus were collected throughout the study period from 2003 to 2007; of these 85 (3.96%) were shedding cercariae. The levels of infection detected by PCR were consistently higher (40-100 percent). Levels of exposure to miracidia in the field were measured using sentinel snails. B. globosus (a susceptible host) and B. nasutus (a non-susceptible host) were placed in cages at transmission sites for 72h to observe rates of penetration by miracidia. Both B. globosus and B. nasutus tested positive for S. haematobium by PCR (up to 24% infected) indicating frequent contamination of the waterbodies with S. haematobium miracidia. The use of sentinel snails coupled with PCR diagnostics could be a sensitive tool for mapping and monitoring transmission of schistosomiasis in areas of low prevalence.
尿路血吸虫病是桑给巴尔的一个重要公共卫生问题。寄生虫向人类传播与中间螺宿主布氏豆螺的分布有关。我们在一系列自然发生的种群中测量了布氏豆螺的丰度和血吸虫的流行程度，并比较了通过观察专利感染的尾蚴脱落和使用 DraI 重复 PCR 检测到的流行率。在 2003 年至 2007 年的研究期间，共收集了 2146 只布氏豆螺；其中 85 只（3.96%）正在脱落尾蚴。PCR 检测到的感染水平始终较高（40-100%）。使用哨螺测量现场接触尾蚴的水平。将布氏豆螺（易感宿主）和布氏纳图斯（非易感宿主）置于传播点的笼子中 72 小时，以观察尾蚴穿透的速度。布氏豆螺和布氏纳图斯均通过 PCR 检测出阳性，表明血吸虫尾蚴频繁污染水体。哨螺结合 PCR 诊断可能是一种在低流行地区绘制和监测血吸虫病传播的敏感工具。
