Aestivation and its impact on the survival of snail intermediate hosts and trematode transmission in rice paddies.

Abstract

In this study, we investigated the diversity and survival of aestivating snails in dry-season rice paddies, focusing on their role as intermediate hosts for trematodes. A total of 1,159 snails from various families were collected and analysed, revealing nine species, primarily from the Bithyniidae family, with Bithynia siamensis siamensis being the most abundant. Of the nine species collected, the most common species, B. s. siamensis, exhibited a relatively high survival rate of 81.5% throughout the three-month dry period post-harvest, whereas the remaining eight species had survival rates below 24.0% (0-23.1%). Four snail species, B. s. siamensis, Filopaludina martensi martensi, F. sumatrensis polygramma, and F. doliaris, were found infected with larval trematodes, with an overall prevalence of 8.46% (57/674). The larval trematodes identified were categorized into four types: echinostome metacercaria, Thapariella anastomusa metacercaria, unidentified metacercaria, and unidentified rediae. These findings demonstrate that trematode infections can persist in aestivating snails despite the challenging conditions during the dry season, emphasizing the potential of aestivating snails to act as vectors for trematode transmission in agricultural settings. This underscores the need for effective management strategies to mitigate the risks associated with trematode transmission.