In this study schistosomiasis research is boosted by developing the first controlled human infection model using female-only Schistosoma mansoni parasites. This innovative approach aims to accelerate vaccine development and deepen our understanding of early immune responses to the disease.
Thirteen healthy, schistosome-naïve adults were exposed to either 10 or 20 female cercariae and monitored over 20 weeks. While most participants experienced mild symptoms like rash or itch, nearly half developed detectable infections despite receiving two rounds of praziquantel (PZQ), the standard treatment. Notably, some infections persisted even after additional treatment, though three participants eventually self-cured.
Immune responses peaked at week 4, showing a mix of Th1, Th2, and regulatory activity. Interestingly, cellular responses were most closely linked to symptom development.
The study found that female-only infections mirror male-only infections in clinical and immune profiles but are more resistant to treatment. This resistance could limit the model’s future use and has important implications for global schistosomiasis control strategies.