Institute of Parasitology, Zhejiang Academy of Medical Sciences, Hangzhou, People's Republic of China.
Parasit Vectors. 2011 Oct 25;4:204. doi: 10.1186/1756-3305-4-204.
Angiostrongylus cantonensis is a zoonotic parasite that causes eosinophilic meningitis in humans. The most common source of infection with A. cantonensis is the consumption of raw or undercooked mollusks (e.g., snails and slugs) harbouring infectious third-stage larvae (L3). However, the parasite is difficult to identify in snails. The purpose of this study was to develop a quick, simple molecular method to survey for A. cantonensis in intermediate host snails.
We used a loop-mediated isothermal amplification (LAMP) assay, which was performed using Bst DNA polymerase. Reactions amplified the A. cantonensis 18S rRNA gene and demonstrated high sensitivity; as little as 1 fg of DNA was detected in the samples. Furthermore, no cross-reactivity was found with other parasites such as Toxoplasma gondii, Plasmodium falciparum, Schistosoma japonicum, Clonorchis sinensis, Paragonimus westermani and Anisakis. Pomacea canaliculata snails were exposed to A. cantonensis first-stage larvae (L1) in the laboratory, and L3 were observed in the snails thirty-five days after infection. All nine samples were positive as determined by the LAMP assay for A. cantonensis, which was identified as positive by using PCR and microscopy, this demonstrates that LAMP is sensitive and effective for diagnosis.
LAMP is an appropriate diagnostic method for the routine identification of A. cantonensis within its intermediate host snail P. canaliculata because of its simplicity, sensitivity, and specificity. It holds great promise as a useful monitoring tool for A. cantonensis in endemic regions.
广州管圆线虫是一种人畜共患寄生虫，可引起人体嗜酸性脑膜炎。感染广州管圆线虫的最常见来源是食用含有感染性第三期幼虫（L3）的生的或未煮熟的软体动物（例如蜗牛和蛞蝓）。但是，寄生虫在蜗牛中很难识别。本研究旨在开发一种快速、简单的分子方法来调查中间宿主蜗牛中的广州管圆线虫。
我们使用了一种环介导等温扩增（LAMP）检测法，该方法使用 Bst DNA 聚合酶进行。反应扩增了广州管圆线虫 18S rRNA 基因，显示出很高的灵敏度；在样本中检测到低至 1fg 的 DNA。此外，与其他寄生虫（如刚地弓形虫、恶性疟原虫、日本血吸虫、华支睾吸虫、卫氏并殖吸虫和异尖线虫）没有交叉反应。在实验室中，Pomacea canaliculata 蜗牛暴露于广州管圆线虫的第一期幼虫（L1），感染后 35 天在蜗牛中观察到 L3。通过 LAMP 检测，所有 9 个样本均为广州管圆线虫阳性，通过 PCR 和显微镜鉴定为阳性，这表明 LAMP 对诊断具有敏感性和有效性。
LAMP 是一种简单、敏感、特异的方法，适用于常规鉴定中间宿主蜗牛 P. canaliculata 中的广州管圆线虫。它作为在流行地区监测广州管圆线虫的有用工具具有很大的潜力。
