Previous observations, which showed that treatment of mice with
hydrocortisone acetate around the time of their
infection with Schistosoma mansoni reduced the mature worm burden, have been confirmed. The number of eggs produced by the surviving worms during early patency was also significantly reduced.
Cyclophosphamide and another
steroid immunosuppressant,
betamethasone, also caused a reduction in fecundity of S. mansoni when given at the time of
infection, as did T-cell deprivation of the mice by adult
thymectomy and injection of anti-thymocyte serum 1 month before
infection. There was no effect of these three treatments on worm numbers. In contrast, injection of mice with anti-thymocyte serum at the time of
infection marginally increased the size of the mature worm burden. The deleterious effects of
hydrocortisone acetate on S. mansoni worm numbers and fecundity were only apparent if the
steroid was given within 1 week of
infection.
Indomethacin, a compound which inhibits tissue inflammatory reactions by inhibiting
prostaglandin synthesis, and which therefore mimics one of the actions of
corticosteroids, had no effect on S. mansoni worm maturation and fecundity.