THE FIRST IN VITRO STUDY OF MEFLOQUINE SCHISTOSOMICIDAL PROPERTIES ON SCHISTOSOMA HAEMATOBIUM IMMATURE STAGE
Rabab Fawzy Mohammad Selem and Maysa Ahmad Eraky
Parasitology Department, Benha Faculty of Medicine, Benha University
Schistosomiasis is a chronic and debilitating disease that exacerbates poverty. About 800 million individuals are at risk of contracting the disease and over 200 million people are thought to be infected. The treatment and control of schistosomiasis virtually relies on a single drug, praziquantel. The pressing need to develop new antischistosomal compounds is hence justified in view of the potential risk of emergence of praziquantel resistant Schistosoma strains .This study investigated the in vitro effect of mefloquine; an antimalarial aminoalcohol recently found to have a promising antischistosomal properties on immature Schistosoma haematobium worms. The in vitro effects of mefloquine were monitored by means of phenotypic evaluation and scanning electron microscopy (SEM). Incubation with 5,10,25,50,75 and 100 μg/ml mefloquine for 1,24 and 48 hours revealed the promising mefloquine antischistosomial properties as it showed a very rapid onset of action on immature Schistosoma haematobium worms in vitro; Incubation of Schistosoma haematobium immature worms with 5,10,25,50,75 and 100 μg/ml mefloquine for 1, 24 and 48 hours resulted in a wide spectrum of phenotypic changes ranged from a minimal altered morphological features and slightly decreased motor activities to rapid worm death accompanied by coiling or flattening according to the parasite status at the time of death. The worm death rate ranged from 0-100% at 1 hour time point, 36.8-100% at 24 hours, and reached up to 100% for all concentrations at 48 hours-time point. There was a strong positive correlation between applied mefloquine concentrations and schistosomes death rates at 1 hour time point. The viability score ranged from 3 down to 0 at 1hour time point,1 to 0 at 24 hours and reached to 0 (total worm death) at 48 hours-time point. A strong negative correlation was found between applied mefloquine concentrations and schistosomes viability score at 1 hour time point. SEM study revealed mild to extensive tegumental disruptions such as blebbing, sloughing, and furrowing and corrugations which is both concentration and time dependent. This study findings hold promise for the development of a novel antischistosomal drug effectively treat Schistosoma haematobium prepatent infection and enhance the potential usage of mefloquine in treatment of schistosomiasis haematobium in humans.