Development, validation, and pilot application of a high throughput molecular xenomonitoring assay to detect and other trematode species within freshwater snail hosts.

Schistosomiasis is a neglected tropical disease (NTD) caused by infection with parasitic trematodes of the genus that can lead to debilitating morbidity and mortality. The World Health Organization recommend molecular xenomonitoring of spp. freshwater snail intermediate hosts of to identify highly focal intestinal schistosomiasis transmission sites and monitor disease transmission, particularly in low-endemicity areas. A standardised protocol to do this, however, is needed. Here, two previously published primer sets were selected to develop and validate a multiplex molecular xenomonitoring end-point PCR assay capable of detecting infections within individual spp. missed by cercarial shedding. The assay proved highly sensitive and highly specific in detecting and amplifying DNA and also proved highly sensitive in detecting and amplifying non- trematode DNA. The optimised assay was then used to screen spp. collected from a endemic area for infection and successfully detected infections missed by cercarial shedding as well as infections with non- trematodes. The continued development and use of molecular xenomonitoring assays such as this will aid in improving disease control efforts, significantly reducing disease-related morbidities experienced by those in schistosomiasis-endemic areas.