Correlation between infection intensity, serum immunoglobulin profile, cellular immunity and the efficacy of treatment with praziquantel in murine Schistosomiasis mansoni

This study was conducted to evaluate the efficacy of praziquantel (CAS 5526 8-74-1, EMBAY 8440, Biltricide(R)) in different grades of Schistosoma manso ni infection. Moreover, the relationship between the post treatment worm bu rden, hepatic granuloma volume, and serum immunoglobin profile was also inv estigated. Four groups of Swiss albino mice infected with Schistosoma mansoni cercaria e were used: Highly infected untreated control mice (infected with 120 Schi stosoma mansoni cercariae) and their corresponding praziquantel treated gro up. Lightly infected untreated control mice (infected with 60 Schistosoma m ansoni cercariae) and their corresponding praziquantel treated group. Prazi quantel was given seven weeks post infection in a dose of 500 mg/kg body we ight for two consecutive days. Animals were sacrificed two weeks post treat ment. Praziquantel achieved better cure rates in mice with heavy infection than i n less intensely infected animals. The drug reduced the hepatic granuloma i n animals with light intensity infection. This reduction was more accentuat ed in highly infected animals. The serum immunoglobulin profile (immunoglob ulin G and immunoglobulin M) showed a higher level in highly infected treat ed mice (1.2 +/- 0.6 optical density unit and 1.1 +/- 0.5 optical density u nit, respectively) and was reduced in animals with low intensity infection (1.18 +/- 0.6 optical density unit and 0.7 +/- 0.6 optical density unit, re spectively). This study may be of value in tropical regions, where schistosomiasis with low worm burden is a common occurrence.