Aiming to determine parasitological and morphological differences between Brazilian strains (CMO, CM and BE) of Schistosoma mansoni the following parameters were studied: prepatent period, kinetics of egg releasing in feces, intestinal oogram, infectivity and the morphology of adult worms. No statistical difference (p>0.05) was found regarding the mean prepatent period (44 and 46 days) and infectivity (26% and 29%). All strains showed a higher concentration of trapped eggs in the small intestine than large intestine (p<0.05). All characteristics of the reproductive system and suckers of male worms presented significant differences (p<0.05). CMO strain was smaller in all measurements. Females showed significant differences (p<0.05) in the larger diameter of the eggs, in the area and perimeter of the spine egg and in the oral sucker area. We conclude that differences in strains can be expressed even when the strains have been cycled for several generations under laboratory conditions.
Schistosoma mansoni; Strains; Parasitological study; Morphology; Mus musculus
