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 55268-74-1, EMBAY 8440, Biltricide) in different grades of Schistosoma mansoni infection. Moreover, the relationship between the post treatment worm burden, hepatic granuloma volume, and serum immunoglobin profile was also investigated. Four groups of Swiss albino mice infected with Schistosoma mansoni cercariae were used: Highly infected untreated control mice (infected with 120 Schistosoma mansoni cercariae) and their corresponding praziquantel treated group. Lightly infected untreated control mice (infected with 60 Schistosoma mansoni cercariae) and their corresponding praziquantel treated group. Praziquantel was given seven weeks post infection in a dose of 500 mg/kg body weight for two consecutive days. Animals were sacrificed two weeks post treatment. Praziquantel achieved better cure rates in mice with heavy infection than in less intensely infected animals. The drug reduced the hepatic granuloma in animals with light intensity infection. This reduction was more accentuated in highly infected animals. The serum immunoglobulin profile (immunoglobulin G and immunoglobulin M) showed a higher level in highly infected treated mice (1.2 +/- 0.6 optical density unit and 1.1 +/- 0.5 optical density unit, 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, respectively). This study may be of value in tropical regions, where schistosomiasis with low worm burden is a common occurrence.