SUMMARYEighteen mongrel dogs of unknown age and naturally infected with Leishmania (Leishmania) chagasi, were obtained from the City Hall of Belo Horizonte, Brazil. Four dogs were used as control. Lung samples were obtained and immediately fixed in formalin. The histopathological picture of all lung tissue sections was a chronic and diffuse interstitial pneumonitis. The thickened interalveolar septa were characterized by the cellular exudate (mostly macrophages, lymphocytes and plasmocytes) associated with collagen deposition. Morphometric analysis showed greater septal thickness in the infected animals than in controls. In fact, the morphometric study of collagen stained with ammoniac silver confirmed a larger deposition of collagen in the infected animals. The parasitologic method was carried out during the study of the lesions on the slides. However, we did not observe any correlation between the histopathologic and morphometric data and the clinical status of the animals. We conclude that the pulmonary lesions observed in all naturally infected dogs were correlated with the disease and that the morphometric method used was satisfactory for the analysis of septal thickness and of increased collagen deposition, confirming the presence of fibrosis.

The aim of this study was to evaluate the diffuse intralobular fibrosis in dogs naturally infected with Leishmania (Leishmania) chagasi. One hundred five infected animals with positive serologic tests for Leishmania were divided into two clinical groups: 69 symptomatic animals and 36 asymptomatic. Special staining with Gomori, Heidenhain, Silver, and Picrosirius Red was applied to characterize fibrilopoesis. The tissue parasite load was measured by immunohistochemistry and associated histomorphometric analyses. Intralobular fibrosis was observed in all dogs, and more collagen deposition was confirmed in the infected animals than in the controls by these histomorphometric studies. There were significant differences among the distinct clinical groups. In fact, symptomatic dogs showed an increased collagen deposition in the liver compared with asymptomatic ones. A peculiar diffuse intralobular fibrosis, where the collagen fibers encircled small groups of hepatocyte(s), was observed in two cases (1.9%).

BackgroundAmerican tegumentary leishmaniasis (ATL) is endemic in Latin America, where Brazil has over 27 thousand cases per year. The aim of the present study was to develop an immunohistochemical method (IHC) for ATL diagnosis. For this purpose, we used serum from a dog naturally infected with Leishmania (L) infantum (canine hyperimmune serum) as the primary antibody, followed by a detection system with a secondary biotinylated antibody.MethodologySkin samples were obtained from 73 patients in an endemic area of Caratinga, Minas Gerais (MG) State, Brazil all testing positive for ATL with the Montenegro skin test, microscopy, and PCR. Canine hyperimmune serum of a dog naturally infected with Leishmania (L.) infantum was employed as a primary antibody in an immunohistochemical diagnostic method using streptavidin-biotin peroxidase. To assess the specificity of this reaction, IHC assays employing two monoclonal antibodies were carried out. As the polymer-based technology is less time-consuming and labor intensive than the IHC labeled streptavidin-biotin peroxidase method, we compared the two methods for all samples.ResultsThe IHC method detected ATL in 67 of the 73 cases (91.8%). Immunolabeled parasites were primarily detected inside macrophages either in the superficial or the deep dermis. Detection was facilitated by the high contrast staining of amastigotes (dark brown) against the light blue background. A lower detection rate (71.2%) was observed with the both of the monoclonal Leishmania antibodies compared to the canine hyperimmune serum. This may have been due to a non-specific background staining observed in all histological samples rendering positive detection more difficult. The higher efficacy of the canine hyperimmune serum in the IHC method was confirmed by the method using streptavidin-biotin peroxidase as well as that with the polymer-based technology (biotin-avidin-free system).ConclusionsThe data are encouraging with regard to validating IHC as a standard alternative method for ATL diagnosis.

BackgroundStrongyloides stercoralis can undergo an alternative autoinfective life cycle in the host, which, in some individuals can lead to a lethal infection. However, due to a number of factors, such as, the majority of those infected are from low-income backgrounds and the limitation in experimental models for studying human S. stercoralis, strongyloidiasis remains neglected. Improved knowledge of animal models that are susceptible to this parasite is needed in order to investigate the immunological mechanisms involved during infection and in particular to further understand the natural history of the autoinfective cycle.MethodsCallithrix penicillata were inoculated subcutaneously with 100 (n = 2), 300 (n = 4) or 500 (n = 9) third-stage infective larvae (L3i) of S. stercoralis of human origin. Three marmosets received smaller inocula (i.e., one received 100 and two received 300 L3i) to ensure a greater capacity to withstand the infection after immunosuppression, which was triggered by administration of dexamethasone during early patency. Qualitative faecal analyses began at 7 days post-infection (DPI), and semi-quantitative tests were also performed for the dexamethasone-treated primates and the three matched controls. During the necropsies, specimens of S. stercoralis were recovered and tissue fragments were processed for histopathology.ResultsThe mean prepatency and patency periods were 16.1 ± 3.0 and 161.1 ± 72.2 DPI, respectively. The marmosets typically tolerated the infection well, but immunosuppressed individuals exhibited higher numbers of larvae in the faeces and progressive clinical deterioration with late disseminated infection. In these cases, the number of females recovered was significantly higher than the number of inoculated L3i. Large quantities of larvae were observed migrating through the host tissues, and histopathology revealed pulmonary and intestinal injuries consistent with those observed in human strongyloidiasis.ConclusionsBoth complicated and uncomplicated strongyloidiasis occur in C. penicillata that is described as a susceptible small non-human primate model for S. stercoralis. This host permits the maintenance of a human strain of the parasite in the laboratory and can be useful for experimental investigations of strongyloidiasis. In parallel, we discuss data related to the autoinfective cycle that provides new insights into the biology of S. stercoralis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-014-0579-2) contains supplementary material, which is available to authorized users.

The authors report one case of late cutaneous Schistosomiasis mansoni in a biopsy of a skin lesion in the sacral region in a 51-year-old female living in Contagem, Minas Gerais. The patient was treated successfully with oxamniquine (Mansil®).