The effect of metrifonate in mixed Schistosoma haematobium and Schistosoma mansoni infections in humans.

In order to examine the effect of metrifonate, 156 patients with mixed Schistosoma haematobium and mansoni infection were randomly divided into three groups and treated with metrifonate (twice 10 mg/kg body weight), oxamniquine (60 mg/kg) and praziquantel (40 mg/kg), respectively. The output of S. haematobium and S. mansoni ova were quantitatively assessed in urine and stool. Application of metrifonate resulted in a similar reduction of S. haematobium and S. mansoni eggs in the urine, whereas no effect on egg excretion was observed in the stool irrespective of the parasite species. In contrast, oxamniquine influenced the output of S. mansoni ova in stool and urine, but showed no effect on S. haematobium egg excretion. praziquantel was equally effective against both parasite species. The chemotherapeutic effects were not of transient nature since the number of ova of both parasite species remained unchanged five months after treatment. The results clearly indicate that metrifonate acted exclusively on adult worms located in the perivesical plexus irrespective of the parasite species.