Schistosoma mansoni: changes in elemental composition in relation to the age and sexual status of the worms.

Changes during development in the elemental contents (Ca, P, K, Mg and S) of male and female Schistosoma mansoni from both mixed and single sex infections have been measured for the first time. In mixed infections, there is a significant difference between the calcium content of male and female worms; female worms having between 2 and 3 times more calcium. In mature female worms from mixed infections, after an initial rise in the calcium content corresponding to the time when vitelline development occurs, the amount of calcium ranged from 0.36 to 0.65 mg/g dry wt, whereas the amounts in similarly aged male worms ranged between 0.19 and 0.32 mg/g dry wt. While the type of infection does not affect the calcium content of male worms, a significant difference in the calcium levels in female worms from mixed and single sex infections was found. The amount of calcium in females from single sex infections ranged from 0.21 to 0.39 mg/g dry wt and this is considerably less than the levels recorded in females from mixed infections. This difference in calcium content between mixed and single sex infections can be related to the differences in degree of development of the vitelline gland in the two types of female worm. The amounts of phosphorus, potassium, magnesium and sulphur in both male and female worms from both single and mixed infections are similar, although females from mixed infections contained slightly more phosphorus than either females from single sex infections or either type of male worm.