Abstract

Early detection ofSchistosoma japonicum(S. japonicum) within its intermediate and definitive hosts is crucial for case finding and disease surveillance, especially in low-endemic areas. Recombinase polymerase amplification (RPA) has many advantages over traditional methods of DNA-amplification, such as polymerase chain reaction (PCR), including high sensitivity and specificity whilst being deployable in resource-poor schistosomiasis-endemic areas. Here, we evaluated the performance of a basic RPA assay targeting the 28srDNA gene fragment ofS. japonicum(Sj28srDNA) using schistosome-infectedOncomelania hupensis(O. hupensis) and mouse models, compared to the traditional pathological method and a PCR assay. OverallS. japonicuminfection prevalence withinO. hupensishosts by microscopic dissection, PCR and RPA was 9.29% (13/140), 32.14% (45/140) and 51.43% (72/140), respectively, presenting significant differences statistically (χ2= 58.31,p< 0.001). It was noteworthy that infection prevalence by PCR and RPA performed was 34.44% (31/90) and 53.33% (48/90) in snails within 6 weeks post-infection, while the dissection method detected all samples as negatives. In addition, the basic RPA assay presented positive results from the fourth week post-infection and third day post-infection when detecting fecal DNA and serum DNA, respectively, which were extracted from a pooled sample from mice infected with 20S. japonicumcercariae. This study suggests that the RPA assay has high potential for early detection ofS. japonicuminfection within its intermediate and definitive hosts.Keywords:Schistosoma japonicum;RPA assay;early detection;infected mice;Oncomelania hupensis