De Novo Transcriptome Assembly and Annotation Elucidate the Response to Extreme Temperature Stress in the Intermediate Host Bulinus globosus of Schistosoma haematobium.

Schistosomiasis remains a major global public health challenge. Bulinus serves as an intermediate host for Schistosoma, including S. haematobium, S. intercalatum, and S. guineensis. Emerging evidence suggests that temperature fluctuations associated with global climate change are key factors influencing the survival and distribution of Bulinus. The ecological shifts in intermediate host snails may significantly influence schistosomiasis transmission dynamics, thereby exacerbating threats to human health. However, the physiological effects of temperature stress on the survival of B. globosus at the molecular level, including gene expression and underlying mechanisms, remain unclear. Our experimental study found that extreme temperature stress significantly reduced the survival rates of Bulinus globosus (B. globosus). De novo transcriptome sequencing revealed key genes associated with lipid metabolism, carbohydrate metabolism, homeostasis regulation, and the antioxidant system. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified significant enrichment of differentially expressed genes (DEGs) in heat shock protein pathways, propanoate metabolism, and N-acylethanolamine metabolism pathways. Overall, this work provides the first transcriptomic characterization of the thermal stress response in B. globosus, extending genomic resources for annotation and stress-related gene discovery. These findings establish a solid foundation for developing control strategies to mitigate climate-driven risks of schistosomiasis transmission.