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.