An experimental study for evaluating the efficacy of cercarial vaccine against Schistosoma mansoni.

This study assessed the effectiveness of autoclaved cercarial vaccine (ACV) in protection against Schistosoma mansoni infection in 125 Swiss albino mice classified into two main groups: GI: a control group. GII: a test vaccinated with ACV, in a single dose of 0.1 ml of 10(4) ml ACV (G.IIa), double dose; 0.2ml (G.IIb) and two single doses 2 weeks apart (G.IIc). Four weeks later, all mice were challenged with S. mansoni cercariae and sacrificed 10 weeks post infection (P.I.). The results revealed that the vaccine in a single dose (G.IIa) induced a high level of protection against S. mansoni infection. There was a significant reduction in the mean number of adult worm (91.12%), ova/gram liver (91.87%), ova/gram intestine (89.09%) and number & size of granulomas in liver (92.92% & 43.53% respectively). Besides, ACV induced a significant increase in the level of IL-10 mRNA expression as compared to the control group.