Evaluation of the antibilharzial activity of mirazid versus praziquantel against S. haematobium: an experimental study

Mirazid [myrrh] is a new herbal extract [oleo gum resin from the stem of the plant Commiphora molmol with claimed antibilharzial activity. LD16, LD50, and LD84 of Mirazid were determined in albino mice and were found to be 1984, 3138, and 4963 mg/kg respectively. The antibilharzial efficacy of Mirazid, administered orally at a dose of 250X5 mg/kg, in comparison to the schistosomicidal drug of choice praziquantel [PZQ], administered orally at a dose of 250X2 mg/kg, was evaluated in S. haematobium infected hamsters. Treatment was conducted 90 days post infection. Parasitological parameters expressing cure and hepatic histopathological changes were evaluated 4 weeks after treatment. Praziquantel treatment completely eradicated S.haematobium worms, caused disappearance of immature and mature egg stages, with 100% dead eggs. Hepatic and intestinal tissue egg loads were reduced by 79.2% and 99.7% respectively. Mirazid failed to induce any significant change in total number of worms, but induced significant reduction in the 1[st], 2[nd], and 3[rd] immature egg stages with increase in the number of the fourth stage, but this change was not reflected on the total number of immature eggs. Mirazid did not affect tissue egg load. The hepatic histopathological changes induced by S. haematobium infection were improved in praziquantel treated hamsters with reduction in granuloma number and size. Ova degeneration with regression of granulomatous inflammatory reaction was more manifested when compared to infected untreated controls. Mirazid did not results in evident regression of hepatic schistosomal pathology. In conclusion, praziquantel is still the drug of choice for treatment of S. haematobium, while Mrazid cannot substitute PZQ in the treatment of S. haematobium. Further trials using modified preparations may result in better antibilharzial efficacy of this novel herbal extract preparation

Immunomodulatory effect of splenectomy and its reflection on curative efficacy of praziquantel in experimental schistosomiasis mansoni

The efficacy of praziquantel [PZQ] treatment was assessed in Schistosomiasis mansoni [S. mansoni] infected splenectomized mice by studying worm burden and distribution, tissue egg load and oogram pattern. Moreover, possible immunomodulation as a result of splenectomy and its reflection on the efficacy of PZQ was assessed as well in this model. Immunomodulation was studied by estimation of immunoglobulin G and M levels and measurement of hepatic granuloma size. Two batches of S. mansoni infected Swiss albino mice were splenectomized 6 weeks post-infection and praziquantel was given at a dose of 500 mg/kg/2 days either 2 days or 2 weeks post splenectomy. Animals were sacrificed 2 days, 1, 2 and 4 weeks post treatment. Unsplenectomized praziquantel treated controls corresponding to the splenectomized groups, were included in the study. PZQ was found to be less effective as an antischistosomal drug when given to splenectomized mice. This has been shown by the increase insignificantly in worm burden and significantly in tissue egg load in splenectomized relative to unsplenectomized animals. Diminution in the efficacy of PZQ was accompanied by a decrease in immunoglobulin profile [IgG and IgM] and a reduction in the mean diameter of hepatic granuloma. These findings may point to the importance of the spleen in the elimination of the active S mansoni infection and to its role in maintenance of humoral and cellular host immune responses