[Performance of loop-mediated isothermal amplification (LAMP) assay for detection of infection in snails in schistosomiasis transmission-interrupted regions].

Objective: To compare the effectiveness of loop-mediated isothermal amplification (LAMP) assay and microscopic examinations for detection of infections in in transmission-interrupted regions, so as to provide insights into the optimization of snail surveillance tools in these regions.

Methods: Four hilly schistosomiasis-endemic villages where transmission interruption was achieved were selected in Heqing County of Yunnan Province as the study villages, including Xinzhuang and Gule villages in hilly regions and Lianyi and Yitou villages in dam regions. Snail survey was performed by means of systematic sampling combined with environmental sampling in July 2018. All captured snails were identified for infections using microscopy. In addition, 10 to 20 snails were randomly sampled from each snail habitat following microscopy, numbered according to environments and subjected to LAMP assay. The positive rate of settings with -infected snails was compared among villages.

Results: A total of 7 949 living snails were captured from 83 snail habitats in 4 villages, and no infection was detected in snails. There were 226 mixed samples containing 1 786 snails subjected to LAMP assay, and positive LAMP assay was found in 3 mixed samples from 3 snail habitats in 2 dam villages. The positive rates of settings with -infected snails were comparable between Lianyi Village (one setting) and Yitou Village (2 set tings) (5.89% vs. 14.29%, = 0.344). However, the overall positive rate of settings with -infected snails was significantly higher in dam villages (9.67%, 3/31) than in hilly villages (0) ( = 0.048).

Conclusions: LAMP assay is more sensitive to detect infections in than conventional microcopy method, which may serve as a supplementary method for detection of infections in in high-risk snail habitats in hilly transmission-interrupted regions.