Lotfy Wael M, Hanelt Ben, Mkoji Gerald M, Loker Eric S
a Parasitology Department, Medical Research Institute, Alexandria University, 165 EI-Horreya Avenue, Alexandria, Egypt, PO Box 21561.
J Parasitol. 2011 Feb;97(1):156-9. doi: 10.1645/GE-2537.1. Epub 2010 Sep 15.
The distribution of Schistosoma genotypes among individuals in snail populations provides insights regarding the dynamics of transmission and compatibility between schistosome and snail hosts. A survey of Biomphalaria alexandrina from Damietta (Nile Delta, Egypt), an area subjected to persistent schistosomiasis control efforts, provided only 17 snails infected with Schistosoma mansoni (6.1% overall prevalence), each shown by microsatellite analysis to have a single genotype infection. By contrast, recent studies of uncontrolled S. mansoni transmission foci in Kenya revealed that 4.3% Biomphalaria pfeifferi and 20-25% Biomphalaria sudanica snails had multiple genotype infections. Compared with the 3 Kenyan populations, the Egyptian population of S. mansoni also showed a lesser degree of genetic variability and was genetically differentiated from them. We suggest that tracking of genotype diversity in infected snails could be further developed to serve as an additional and valuable independent indicator of efficacy of schistosomiasis control in Egypt and elsewhere.
血吸虫基因型在钉螺种群个体中的分布情况，为了解血吸虫与钉螺宿主之间的传播动态和兼容性提供了线索。对来自埃及尼罗河三角洲达米埃塔的亚历山大双脐螺进行的一项调查显示，在这个长期开展血吸虫病防治工作的地区，仅发现17只感染曼氏血吸虫的钉螺（总体感染率为6.1%），经微卫星分析表明每只钉螺均为单一基因型感染。相比之下，最近对肯尼亚未受控制的曼氏血吸虫传播疫点的研究发现，4.3%的费氏双脐螺和20 - 25%的苏丹双脐螺存在多种基因型感染。与肯尼亚的3个种群相比，埃及的曼氏血吸虫种群的遗传变异性也较低，且在基因上与它们有所分化。我们建议，对感染钉螺的基因型多样性进行追踪，可进一步发展成为埃及及其他地区血吸虫病防治效果的一项额外且有价值的独立指标。
