CRISPR/Cas9-germline editing of Biomphalaria glabrata: A breakthrough in genetic modification of snails that transmit schistosomiasis.

Human schistosomiasis remains one of the most devastating parasitic diseases worldwide, and the development of genetically modified vector snails has long been a goal in the field. Here, we report the successful creation of genetically modified Biomphalaria glabrata, an important intermediate host, using CRISPR/Cas9 gene editing. We targeted the fibrinogen-related protein 3.1 (FREP3.1) gene, confirmed stable germline transmission of the mutated gene, and established two different homozygous FREP3.1-edited lines. Disruption of the FREP 3.1 gene did not alter snail susceptibility to Schistosoma mansoni infection, possibly due to a limited role of FREP3.1 in resistance or to functional redundancy and/or compensatory expression within the highly diverse FREP gene family. Our study demonstrates successful germline editing, effective ex ovo culture of decapsulated embryos, and the generation of viable, genetically modified B. glabrata snails, thereby establishing a foundation for future genetic strategies to control schistosomiasis.