Browsing by Subject "Susceptibility"

Now showing 1 - 2 of 2
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    Leishmania amazonensis isolated from human visceral leishmaniasis: histopathological analysis and parasitological burden in different inbred mice
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Freitas de Souza, Celeste da Silva; Calabrese, Kátia da Silva; Abreu Silva, Ana Lúcia; Pereira Carvalho, Luiz Otávio; de Oliveira Cardoso, Flávia; Moraes Cavalheiros Dorval, Maria Elizabeth; Teruya Oshiro, Elisa; Quaresma, Patrícia Flávia; Ferreira Gontijo, Célia Maria; da Silva Pacheco, Raquel; Doria Rossi, Maria Isabel; Gonçalves da Costa, Sylvio Celso; Zaverucha do Valle, Tânia
    Leishmania amazonensis is a major etiological agent of human cutaneous leishmaniasis in the Americas; nevertheless there are some reports of this species causing visceral disease in dogs and men. In the present work we have studied a Leishmania strain isolated from a human case of visceral leishmaniasis. We have infected different mouse strains and analyzed the development of the disease, studying the parasite’s ability to visceralize and whether this ability is influenced by host genetics. Female BALB/c, C57BL/6, C57BL/10, CBA, DBA/2, and C3H/He mice were subcutaneously infected with 104 L. amazonensis amastigotes. BALB/c, C57BL/6 and C57BL/10 mice were found to be very susceptible to infection, showing lesions that developed to necrosis and ulceration. CBA mice developed a late but severe lesion. DBA/2 mice developed only discrete lesions, while C3H/He mice did not develop any lesions. All mouse strains except C3H/He showed some degree of visceralization, presenting parasites in the spleen, while BALB/c, C57BL/6 and CBA presented parasites also in the liver. Moreover, most of the strains presented high parasite load at the infection site, whereas DBA and C3H/He mice showed low or no parasite load 90 days after infection, respectively. Histopathology corroborates the results, showing that susceptible mice presented an inflammatory reaction with parasites in the skin, lymph nodes and spleen, while strains that are more resistant presented low parasitism and discrete inflammatory reaction. Results indicate that this isolate is extremely virulent, can easily visceralize and that the pathogenesis of leishmaniasis is, at least in part, related to the genetic background of the host.
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    Trypanosoma cruzi infection patterns in intact and athymic mice of susceptible and resistant genotypes
    (Murcia : F. Hernández, 2002) Gonçalves da Costa, S.C.; Calabrese, K.S.; Zaverucha do Valle, T.; Lagrange, P.H.
    Inbred strains of mice inoculated with the T. cruzi Y strain behaved as susceptible (A/J, C3H/HeN), intermediate (BALB/c) or relatively resistant (C57BL/6) with respect to the magnitude of parasitaemia and mortality rate. C57BL/10 mice were susceptible in relation to parasitaemia but resistant when mortality was analyzed. Infection with T. cruzi CL strain presented the same results, except for C57BL/6 which behaved as susceptible mice. Athymic mice of various backgrounds revealed no differences in susceptibility, presenting the same dramatic parasitaemia, tissue colonization pattern and no inflammatory reaction in any of the tissues studied. Infection of euthymic and athymic BALB/c mice elicited the production of parasite-specific antibodies, which reached similar levels on the first 9 days but differed after day 13. Serum transfer experiments in BALB/c mice did not show great differences in parasitaemia but altered T. cruzi polymorphism reducing the slender forms in athymic mice. Histopathology of athymic BALB/c mice showed the same tissue tropism when infected either with T. cruzi Y or CL strain.