ABSTRACT
Praziquantel [PZQ] efficacy is known to depend in part on the host immune response to infection. The study of schistosomal cases that resist or tolerate PZQ therapy after multiple doses includes the host immune system, the drug and the schistosomes characters In the present work, a trial to assess serum trace elements [Zinc and Copper] by Atomic absorption spectrometry and to evaluate humoral imrnune response of susceptible [cured] and resistant [non-cured] schistosomal cases for PZQ therapy by ELISA to measure antischistosomal antibodies [Anti-SWAP IgG and 1gM] of schistosomal cases in a rural area of Nile Delta of Egypt. There are insignificant variations of serum trace elements [Zinc and Copper] levels between 4 different groups of schistosomal cases that received single, double [40 mg/kg] and triple doses [60 mg/kg b.w.] of PZQ, while serum Copper among schistosomal cases are significantly higher than healthy control cases. These results may denote that PZQ cannot affect trace elements levels among different groups of schistosomal cases. Moreover, no significant variations in the level of the schistosomal antibodies [Anti-SWAP IgG and IgM] among different groups of schistosomal cases which may indicate on the integrity of immune response of infected cases either susceptible or resistant cases for PZQ therapy. The detection of few schistosomal cases resist or tolerate [innate insusceptibility] PZQ after 3 doses may guide to resistant strains of schistosomes to P29 therapy especially with drug abuse that may confirm the need for further studies to elucidate etiological factors for drug resistance because PZQ is the milestone in the chemotherapeutic control of schistosomiasis