Dynamic changes of gut microbiota in Oncomelania hupensis caused by Schistosoma japonicum infection

Schistosomiasis (bilharzia) is a neglected tropical disease caused by parasitic flatworms (blood flukes) of the genus Schistosoma. According to estimates, over 251.4 million people worldwide are in need of preventive treatment for this disease. The freshwater amphibious snail Oncomelania hupensis serves as the obligate intermediate host of Schistosoma japonicum. The microbiome is known to play key roles in health and disease, including host susceptibility to parasite infections. However, the precise mechanisms driving these host-microbe interactions have yet to be explored. The aim of this study was to analyze the gut microbiota in O. hupensis and identify core microbiota during the intramolluscan development of S. japonicum. To achieve this, the obtained snail gut samples were subjected to DNA extraction and then 16S rRNA gene sequencing. The findings of our study revealed a total of 1433 operational taxonomic units (OTUs). Proteobacteria, Firmicutes, and Bacteroidetes were identified as the dominant bacterial taxa at the phylum level. Streptococcus and Bacillus were the most common genera in samples obtained from O. hupensis. We discovered a homeostatic imbalance and a decline in diversity in the gut microbiota of O. hupensis due to schistosome infection. In order to discern important microbiota during the intramolluscan development of S. japonicum, we utilized LEfSe and random forest classifiers to identify a series of key microbiota. In summary, infection and development of S. japonicum have an impact on the variety displayed by the gut microbiota in O. hupensis. Our research will deepen our comprehension of the mechanism governing the interaction between O. hupensis and S. japonicum, with the aim to develop microbiota-based strategies for controlling snail populations and reducing their competence in transmitting parasites.