PNP and infection: The results of this study demonstrated that the treatment with the recombinant enzymes of S. mansoni HGPRT, PNP and MIX seems to cause a reduction in the parasitic load and, consequently, interfere in the lifecycle of the worm, decreasing the posture of the eggs, infection and its consequences and the PNP enzyme alone was able to generate an important reduction in the number of worms in BALB/c mice.