HOST-INDUCED MORPHOLOGICAL-CHANGES OF SCHISTOSOMA-MANSONI SAMBON, 1907 MALE WORMS

In order to evaluate the permissiveness of Nectomys squamipes to Schis tosoma mansoni and the influence of the albino mice on the morphologic al aspects of adult worms derived from a population isolated from N. s quamipes, the morphology of adult S. mansoni Sambon, 1907 male worms w as studied using a digital image analyser (MOP VIDEOPLAN) and light mi croscopy. Their sources were as follows: (1) recovered from the wild r odent N. squamipes Brants naturally infected from Sumidouro, RJ, Brazi l; (2) recovered from albino mice experimentally infected with the str ain derived from N. squamipes; (3) recovered after the is olation of a strain derived from aboriginal human infections in Sumidouro. Worms r ecovered from N. squamipes (group 1) showed body length and distance b etween suckers significantly bigger than those of the specimens mainta ined in mice (groups 2 and 3). The number of testes in group 1 was sta tistically less than that of groups 2 and 3. Group 2 strains which wer e maintained in mice, presented the length of the worms as the only si gnificant different character. Data show that: (1) N. squamipes is a m ore suitable host for the development of S. mansoni when compared to t he albino mice; (2) a strain of S. mansoni isolated from a natural hos t undergoes morphological changes after its passage in the white mouse .