Morphologic Changes due to Cutaneous Leishmaniosis in BALB/c Mice Experimentally Infected with Leishmania major

BALB/c mice were injected subcutaneously in hind footpad with 10⁶ promastigotes of Leishmania major. At various times, two mice each were euthenised and their skin, popliteal lymph nodes, spleen, liver and femoral bone marrow were removed and processed for histopathological and ultrastructural evaluation and for Specific PCR to confirm the presence of L. major infection. Diffuse infiltration by histiocytes, lymphocytes and plasma cells of the dermis and subcutaneous tissues of the infected skin was found along with small granulomas containing macrophages, lymphocytes and plasma cells. Follicular hyperplasia and sinus histiocytosis consisting of lymphocytes and plasma cells were evident in the lymph nodes and spleen. Sinusoid dilatation of liver and infiltration of lymphocytes, macrophages and plasma cells were demonstrated in the portal spaces of the liver. The amastigote form of the protozoa was clearly visible in the intracytoplasmic vacuoles of the femoral bone marrow macrophages. The PCR performed on tissues revealed infection by L. major. The results showed that, the femoral bone marrow was the tissue of choice for identification of amastigote form of L. major in experimentally infected BALB/c mice.