Schistosoma japonicum, the Asian schistosome, is a zoonotic parasite that infects humans and more than 40 species of domestic animals. It is a principal causative agent of schistosomiasis, a neglected tropical disease that affects approximately 240 million people worldwide and contributes an estimated 2.5 million disability-adjusted life years (DALYs) annually. In endemic regions, bovines are responsible for 75–90% of environmental egg contamination, positioning them as major reservoirs that perpetuate transmission. Current control efforts rely heavily on chemotherapy with Praziquantel, which, while effective at reducing worm burdens, does not prevent reinfection and may contribute to drug resistance if used as a sole intervention. These limitations highlight the urgent need for integrated strategies to achieve sustainable control.
Mathematical modelling has indicated that coupling chemotherapy with an effective transmission-blocking vaccine (TBV) could achieve elimination of S. japonicum within a decade. In this context, my PhD project seeks to develop a TBV by evaluating parasite-derived proteins with demonstrated immunogenicity and protective potential. One objective is an mRNA vaccine encapsulated in lipid nanoparticles encoding the open reading frame (ORF) of S. japonicum paramyosin (Sjpmy), a structural protein essential for muscular function and implicated in immune evasion. Preliminary murine trials of Sjpmy-mRNA-LNP demonstrated significant reductions in worm and egg burdens, as well as alleviation of liver pathology. Additional investigations are exploring other vaccine candidates, including S. japonicum schistosomulum protein 25 (SjSP25), to assess their protective efficacy. The integration of such promising antigens in a multivalent mRNA vaccine represents a rational strategy to maximize protection and durability of response.
Collectively, these findings highlight the potential of a TBV to significantly reduce bovine- and human-driven transmission of S. japonicum. Integration of such vaccines with chemotherapy offers a promising pathway toward sustainable schistosomiasis control and improved global public health outcomes.