(A) Fecundity of the worm population, revealed by fecal egg output reached its peak at week 8, dropped sharply thereafter and then more slowly reached zero, at the end of the study. The level of soluble circulating anodic antigen (CAA, expressed as the ratio of test/control) released in the bloodstream of rhesus macaques, an indicator of worm blood feeding and gut function, was already high at week 4 but started declining after week 12. Values are mean + or—SE, n = 6 animals. (B) The body weight of monkeys increased during the first 4 weeks after infection, declined thereafter reaching the minimum value at week 8 but then gradually recovered towards the weak 4 peak weight by the end of the study. Values are mean + or–SD, n = 6 animals.