The effect of multiple doses of antimonials in Schistosoma mansoni infection.

The treatment of bilharziasis with antimonials has been carried out in the past in a rather arbitrary manner, dosage levels and schedules varying widely and being based on little valid experimental evidence. The author has therefore attempted to determine the optimum dosage intervals with tartar emetic for cure of mice experimentally infected with Schistosoma mansoni.It was already known that schistosomes are swept back into the liver when their level of antimony reaches a certain threshold but that, once that level drops, they re-migrate back to the mesenteric veins. In this work, therefore, the schedule of treatment was arranged so as to relate the intervals between doses to the re-migration of worms to the mesentery. It is shown that there is probably a direct relationship between the number of doses and the total period of time during which the schistosomes can be kept in the liver, so that relatively few doses given at short intervals may be as effective as a larger number of doses at longer intervals.