A histological, morphometric and immunocytochemical study of schistosomal periovular granulomas in the liver and intestines of mice revealed that intestinal granulomas are smaller and contain less collagen than those in the liver. After curative treatment intestinal granulomas undergo a relatively more rapid resorption, although the general pattern of collagen degradation apparently does not differ from that observed in the liver. Tendency to form scattered, usually isolated granulomas that are only mildly fibrogenic, coupled with a well-balanced process of resorption appear as the explanation why intestinal fibrosis is not an outstanding feature of schistosomiasis as it is in the liver.

Casais de camundongos isogênicos das raças CBA, BALB/c e machos e fêmeas de Swiss heterogenéticos criados no sistema convencional, que se encontravam infectados em diferentes graus por Myobia musculi e Myocoptes musculinus, foram submetidos a quatro esquemas de tratamento com Tetmosol. A incidência de ectoparasitas na raça C57BL/10 foi apenas 1,2%. Todos os animais da raça CBA e Swiss encontravam-se parasitados, enquanto que a infestação do BALB/c foi de 50 a 90%. Os melhores resultados dos 4 esquemas de tratamento testados foram observados utilizando-se Tetmosol na concentração 2,5% em banhos seriados com intervalos alternados de 3 e 4 dias, num período de 21 dias. A incidência de ectoparasitas adultos em CBA, BALB/c e Swiss após o tratamento foi de respectivamente 0%, 40% e 0%, enquanto que para ovos viáveis os respectivos resultados foram de 20%, 50% e 0%. Após a introdução de matrizes tratadas num sistema de criação sob barreiras, a colônia tem sido examinada sistematicamente há 24 meses e encontra-se isenta de ectoparasitas.

Colonies of CBA, C57BL/10, BALB/c and Swiss mice housed in conventional systems were found to be infected to different degrees with both Myobia musculi and Myocoptes musculinus. Groups of ten different sister-brother pairs of the isogenic mice and groups of 25 mice separated according to were infected by the parasite and then submitted to 4 different schemes of treatment with Tetmosol. C57BL/10 presented a very low incidence of parasites (1.2%). Every pair of CBA, and every Swiss mice examined, were found to be infected while only 50-90% of the pairs of BALB/c mice were infected. The best results of four different schemes were obtained by dipping the animals in 2.5% Tetmosol, at 3-4 days intervals for 21 days. The incidence of adult parasite forms in CBA, BALB/c and Swiss mice were found to be 0%, 40% and 0%, respectively, while in viable eggs it was found to be 20%, 50% and 0%, respectively.

Casais de camundongos isogênicos das raças CBA, BALB/c e machos e fêmeas de Swiss heterogenéticos criados no sistema convencional, que se encontravam infectados em diferentes graus por Myobia musculi e Myocoptes musculinus, foram submetidos a quatro esquemas de tratamento com Tetmosol. A incidência de ectoparasitas na raça C57BL/10 foi apenas 1,2%. Todos os animais da raça CBA e Swiss encontravam-se parasitados, enquanto que a infestação do BALB/c foi de 50 a 90%. Os melhores resultados dos 4 esquemas de tratamento testados foram observados utilizando-se Tetmosol na concentração 2,5% em banhos seriados com intervalos alternados de 3 e 4 dias, num período de 21 dias. A incidência de ectoparasitas adultos em CBA, BALB/c e Swiss após o tratamento foi de respectivamente 0%, 40% e 0%, enquanto que para ovos viáveis os respectivos resultados foram de 20%, 50% e 0%. Após a introdução de matrizes tratadas num sistema de criação sob barreiras, a colônia tem sido examinada sistematicamente há 24 meses e encontra-se isenta de ectoparasitas.

Colonies of CBA, C57BL/10, BALB/c and Swiss mice housed in conventional systems were found to be infected to different degrees with both Myobia musculi and Myocoptes musculinus. Groups of ten different sister-brother pairs of the isogenic mice and groups of 25 mice separated according to were infected by the parasite and then submitted to 4 different schemes of treatment with Tetmosol. C57BL/10 presented a very low incidence of parasites (1.2%). Every pair of CBA, and every Swiss mice examined, were found to be infected while only 50-90% of the pairs of BALB/c mice were infected. The best results of four different schemes were obtained by dipping the animals in 2.5% Tetmosol, at 3-4 days intervals for 21 days. The incidence of adult parasite forms in CBA, BALB/c and Swiss mice were found to be 0%, 40% and 0%, respectively, while in viable eggs it was found to be 20%, 50% and 0%, respectively.

Immunological tolerance to Schistosoma mansoni antigens induced by oral exposure of neonatal and adult mice to adult worm, soluble egg and polysaccharide antigens conducted to modulated periovular granuloma of infected mice. However the tolerance do not interfere in the infection. The estimative population and subpopulation of lymphocytes in the spleen of tolerized (not infected) animals do not differ from normal animals but Lyt 2.2 reactive lymphocytes to Schistosoma antigens was demonstrated in the tolerized animals.