Background 240-million people have schistosomiasis despite decades of interventions. Infections cannot be directly observed, and egg-based Kato-Katz thick smears lack sensitivity, impacting treatment efficacy and reinfection rate estimates. The Point-of-Care Circulating Cathodic Antigen test (POC-CCA) is advocated as an improvement upon the Kato-Katz, however improved estimates are limited by ambiguities in the interpretation of Trace results. Method We collected repeated Kato-Katz counts from 210 school-aged children and scored POC-CCAs according to manufacturer’s guidelines (POC-CCA+) and the externally developed G-Score. We used Hidden Markov Models parameterised with Kato-Katz; Kato-Katz and POC-CCA+; and Kato-Katz and G-Scores, inferring latent clearance and reinfection probabilities at four timepoints over six-months through a more formal statistical reconciliation of these diagnostics than previously conducted. Our approach required minimal but robust assumptions regarding Trace interpretations. Results Antigen-based models estimated higher infection prevalence across all timepoints compared with the Kato-Katz model, corresponding to lower clearance and higher reinfection estimates. Specifically, pre-treatment prevalence estimates were 85% (Kato-Katz; 95% CI: 79-92%), 99% (POC-CCA+; 97-100%) and 98% (G-Score; 95-100%). Post-treatment, 93% (Kato-Katz; 88-96%), 72% (POC-CCA+; 64-79%) and 65% (G-Score; 57-73%) of those infected were estimated to clear infection. Of those who cleared infection, 35% (Kato-Katz; 27-42%), 51% (POC-CCA+; 41-62%) and 44% (G-Score; 33-55%) were estimated to have been reinfected by nine-weeks. Conclusion Treatment impact was shorter-lived than only Kato-Katz-based estimates suggested, with lower clearance and rapid reinfection. Three-weeks-post-treatment captured longer-term clearance dynamics. Nine-weeks-post-treatment captured reinfection, but alone could not discern between failed clearance and rapid reinfection. Therefore, frequent sampling is required to understand these important epidemiological dynamics.

Schistosoma mansoni is a parasite which causes significant public-health issues, with over 240 million people infected globally. In Uganda alone, approximately 11.6 million people are affected. Despite over a decade of mass drug administration in this country, hyper-endemic hotspots persist, and individuals who are repeatedly heavily and rapidly reinfected are observed. Human blood-type antigens are known to play a role in the risk of infection for a variety of diseases, due to cross-reactivity between host antibodies and pathogenic antigens. There have been conflicting results on the effect of blood type on schistosomiasis infection and pathology. Moreover, the effect of blood type as a potential intrinsic host factor on S. mansoni prevalence, intensity, clearance, and reinfection dynamics and on co-infection risk remains unknown. Therefore, the epidemiological link between host blood type and S. mansoni infection dynamics was assessed in three hyper-endemic communities in Uganda. Longitudinal data incorporating repeated pretreatment S. mansoni infection intensities and clearance rates were used to analyse associations between blood groups in school-aged children. Soil-transmitted helminth coinfection status and biometric parameters were incorporated in a generalised linear mixed regression model including age, gender, and body mass index (BMI), which have previously been established as significant factors influencing the prevalence and intensity of schistosomiasis. The analysis revealed no associations between blood type and S. mansoni prevalence, infection intensity, clearance, reinfection, or coinfection. Variations in infection profiles were significantly different between the villages, and egg burden significantly decreased with age. While blood type has proven to be a predictor of several diseases, the data collected in this study indicate that it does not play a significant role in S. mansoni infection burdens in these high-endemicity communities.