Circadian rhythm in Schistosoma haematobium egg excretion

The usual peak daily egg excretion period in persons harbouring Schistosoma haematobium is the late morning and early afternoon. No evidence was found to support a hypothesis that the rhythm is mechanical in origin being due to rapid increase of bladder activity in the early morning.A partial reversion of the rhythm occurred when day shift workers changed to night shift.The possible role in the circadian rhythm of host factors—temperature and metabolism and of proteolytic enzyme secretion by miracidia are discussed.