School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya.
Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya.
Am J Trop Med Hyg. 2019 Jul;101(1):65-77. doi: 10.4269/ajtmh.19-0089.
Following a 4-year annual praziquantel (PZQ) treatment campaign, the resulting prevalence of was seen to differ among individual villages along the Kenyan shore of Lake Victoria. We have investigated possible inherent differences in snail-related aspects of transmission among such 10 villages, including six persistent hotspot (PHS) villages (≤ 30% reduction in prevalence following repeated treatments) located along the west-facing shore of the lake and four PZQ-responding (RESP) villages (> 30% prevalence reduction following repeated treatment) along the Winam Gulf. When taking into account all sampling sites, times, and water hyacinth presence/absence, shoreline-associated from PHS and RESP villages did not differ in relative abundance or prevalence of infection. Water hyacinth intrusions were associated with increased abundance. The deeper water snail was significantly more abundant in the PHS villages, and prevalence of among villages both before and after control was positively correlated with abundance. Worm recoveries from sentinel mice did not differ between PHS and RESP villages, and abundance of non-schistosome trematode species was not associated with abundance. provides an alternative, deepwater mode of transmission that may favor greater persistence of in PHS villages. As we found evidence for ongoing transmission in all 10 villages, we conclude that conditions conducive for transmission and reinfection occur ubiquitously. This argues for an integrated, basin-wide plan for schistosomiasis control to counteract rapid reinfections facilitated by large snail populations and movements of infected people around the lake.
在为期 4 年的年度吡喹酮(PZQ)治疗活动之后,维多利亚湖肯尼亚沿岸各个村庄的流行率存在差异。我们研究了这些 10 个村庄中与蜗牛相关的传播方面的固有差异,包括沿湖西岸的 6 个持续热点(PHS)村庄(重复治疗后流行率降低≤30%)和沿威纳姆湾的 4 个 PZQ 反应(RESP)村庄(重复治疗后流行率降低>30%)。当考虑到所有采样地点、时间和水葫芦的存在/缺失时,来自 PHS 和 RESP 村庄的与岸线相关的蜗牛在相对丰度或感染的流行率方面没有差异。水葫芦入侵与增加的蜗牛丰度有关。在 PHS 村庄,深水区蜗牛的数量明显更多,而且在控制前后,村庄的流行率与蜗牛的丰度呈正相关。从哨兵小鼠中回收的蠕虫在 PHS 和 RESP 村庄之间没有差异,并且非血吸虫吸虫物种的丰度与蜗牛的丰度无关。水葫芦提供了一种替代的、深水区的传播方式,可能有利于 PHS 村庄中蜗牛的持续存在。由于我们在所有 10 个村庄都发现了持续传播的证据,因此我们得出结论,有利于传播和再感染的条件普遍存在。这就要求制定一个综合性的、全流域的血吸虫病控制计划,以对抗由大量蜗牛种群和受感染人群在湖泊周围的流动所带来的快速再感染。