Abou-El-Naga Iman F, El-Nassery Suzanne M F, Allam Sonia R, Shaat Eman A, Mady Rasha F M
Medical Parasitology Department, Faculty of Medicine, University of Alexandria, Alexandria, Egypt.
Parasitol Int. 2011 Sep;60(3):247-54. doi: 10.1016/j.parint.2011.03.006. Epub 2011 Mar 31.
Of the several species of Biomphalaria snails worldwide that serve as the intermediate host for Schistosoma mansoni, Biomphalaria alexandrina is a species that is indigenous to Egypt. Recently, there has been much debate concerning the presence of Biomphalaria glabrata and the hybrid of the species with Biomphalaria alexandrina. Due to this debate, the absence of a clear explanation for the presence of B. glabrata in Egyptian water channels and the probability that they may be reintroduced, we conducted this field study to identify Biomphalaria species present in Alexandria water channels. Laboratory-adapted susceptible snails to Schistosoma mansoni of the following species were used as a reference; Biomphalaria alexandrina, Biomphalaria glabrata and their hybrid. These snails were used to perpetuate the Schistosoma life cycle at the Theodor Bilharz Research Institute (TBRI), Cairo, Egypt. Morphological and molecular studies were conducted on these reference snails as well as on the first generation of Biomphalaria snails from two areas in the Alexandria governorate. The morphological study included both external shell morphology and internal anatomy of the renal ridge. The molecular study used a species-specific PCR technique. The results demonstrated that there was an absence of Biomphalaria glabrata and the hybrid from Alexandria water channels. Moreover, the susceptibility patterns of these reference snails were studied by measuring the different parasitological parameters. It was found that Biomphalaria glabrata and the hybrid were significantly more susceptible than Biomphalaria alexandrina to the Egyptian strain of Schistosoma mansoni. The results demonstrated that if Biomphalaria glabrata was reintroduced and adapted to the local environment in Egypt, it would have important epidemiologic impacts that would have a serious effect on the health of Egyptian people.
在全球范围内，作为曼氏血吸虫中间宿主的几种双脐螺属蜗牛中，亚历山大双脐螺是埃及本土的一个物种。最近，关于光滑双脐螺的存在以及该物种与亚历山大双脐螺的杂交种存在诸多争议。由于这场争论，对于埃及水道中光滑双脐螺的存在缺乏明确解释，且它们可能被重新引入，我们开展了这项实地研究，以确定亚历山大水道中存在的双脐螺物种。以下物种的实验室适应的对曼氏血吸虫易感的蜗牛被用作参考：亚历山大双脐螺、光滑双脐螺及其杂交种。这些蜗牛曾在埃及开罗的 Theodor Bilharz 研究所（TBRI）用于维持血吸虫的生命周期。对这些参考蜗牛以及来自亚历山大省两个地区的第一代双脐螺进行了形态学和分子研究。形态学研究包括外壳形态和肾嵴的内部解剖结构。分子研究采用了物种特异性 PCR 技术。结果表明，亚历山大水道中不存在光滑双脐螺及其杂交种。此外，通过测量不同的寄生虫学参数研究了这些参考蜗牛的易感性模式。发现光滑双脐螺及其杂交种比亚历山大双脐螺对埃及曼氏血吸虫菌株的易感性显著更高。结果表明，如果光滑双脐螺被重新引入并适应埃及当地环境，将会产生重要的流行病学影响，对埃及人民的健康造成严重影响。
