BackgroundInfection with parasite protozoa is a long-term health issue in tropical and subtropical regions throughout the world. The Toll-like receptor (TLR) signaling pathway is one of the first-responding defense systems against Leishmania. The aim of this study was to investigate the expression of TLR2 and TLR9 in jejunum and colon and its correlation with CD11c, CD11b, and CD14 receptors used as markers for dendritic cells and macrophages.MethodsTwenty four dogs infected with Leishmania infantum were used in this study. Cytometry was carried out in lamina propria cells from jejunum and colon using markers for TLR2, TLR9, CD11b, CD11c and CD14.ResultsCellular inflammatory exudate was diffuse in the mucosa and submucosa, predominately comprising mononuclear cells: plasma cells, macrophages, and lymphocytes. Despite the parasite load, microscopy showed no erosion was evident in the epithelial mucosa layers. The colon harbored more parasites than the jejunum. Flow cytometry revealed higher frequency of TLR2+ and CD11c+ dendritic cells in the colon than in the jejunum. Conversely, TLR9-expressing cells were more frequent in jejunum. Moreover, frequency of macrophages (CD11b+ and CD14+) expressing simultaneity TLR9 were lower in the colon than in jejunum, while CD11c+ cells predominated in the colon. Despite of the negative ELISA serum results, IL-10 and TNF-α were higher in jejunum than colon of infected animals. However, IL-4 was higher in colon than jejunum of infected animals. A higher expression these cytokines were demonstrated in infected dogs compared to uninfected dogs.ConclusionsThere was no correlation between clinical signs and pathological changes and immunological and parasitological findings in the gastrointestinal tract in canine visceral leishmaniasis. However, jejunum showed a lower parasite load with increased frequency and expression of CD11b, TLR9, CD14/CD11b/TLR9 receptors and IL-10 and TNF-α cytokines. Conversely, the colon showed a higher parasite load along with increased frequency and expression of TLR2, CD11c receptors, and IL-4 cytokine. Thus, Leishmania infantum is able to interfere in jejunum increased expression of TLR2, TLR9, CD11b, CD14, CD14/CD11b/TLR9 receptors, IL-10, and TNF-α; and in colon increased expression of CD11c, TLR2, TLR9, CD11b, CD14 e, CD14/CD11b/TLR9 receptors, IL-10, and TNF-α.

In dogs, a parasite burden is evident throughout the gastrointestinal tract but not is observed pathological alterations. Our aim was isolating lamina propria cells from dogs infected with leishmaniasis to further investigate if the parasite in the gut is correlated with the pathogenesis of the visceral infection. The biopsies were obtained of dogs and incubated with collagenase II. In the cells suspension was added antibodies against superficial and intracellular markers. Few studies of the markers used in this work have been done in the lamina propria cells in leishmaniasis. It is of great importance to determine markers in this tissue especially those who are described as being involved with the persistence of Leishmania infection within cells due to the fact that the infection in the gut does not induce lesions. Furthermore, work is ongoing in terms of investigating other segments of the GIT, a systematic study, from dogs with Leishmania

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The present study aimed to analyze the epidemiology of Visceral Canine Leishmaniasis (VCL) in the municipality of Itaporanga-PB between the years 2015 and 2016. 180 records of notification and investigation of suspected dogs deposited at the Municipal Health Department were retrieved, where the variables were analyzed using the absolute number and relative frequency, applying the chi-square test. The seroprevalence corresponded to 13,3% when associated to two diagnostic methodologies: rapid immunochromatographic test (TR DPP®) and ELISA (EI LCV). Of the 24 seropositive dogs, male (70,8%), undecided (79,2%), urban area (70,8%) and age greater than two years (70,8%) prevailed. The analysis of the clinical signs revealed statistical significance and presence of risk between alopecia (p= 0,001; OR= 7,474; PR= 4,237) and multiple wounds (p= 0,000; OR= 7,667; PR= 4,529) with seropositivity. Seroprevalence in Itaporanga-PB was compared to other municipalities in Paraíba, Northeast and Brazil, and the other variables and risk factors were discussed with the literature. Due to the epidemiological situation of the city, the continuation of canine serological surveys in subsequent years and the application of other prophylactic measures for parasitosis.

Visceral Leishmaniasis is a chronic and lethal, parasitic disease. In the later infection stages, it is known that expressive hematological disorders can be observed, including changes in the frequency and phenotype of certain leukocytes. There is a lack of good prognostic indicators to characterize the on-goin clinical status of the patient. In this study, we have analyzed the frequency of monocyte subpopulations in mice infected with Leishmania major (L. major). Our results show a significant correlation between increased blood monocyte frequency and lesion development in both BALB/c and in the C57BL/6 mice infected with L. major. In BALB/c mice we observed a significant correlation between the frequency of GR1 monocytes and lesion size. Furthermore, treatment of infected BALB/c mice with Anfotericin B, to resolve lesions, resulted in a lower frequency of GR1 monocytes compared to untreated infected BALB/c mice. C57BL/6 infected mice, which normally resolve infections, show decreased numbers of monocytes during the healing phase of infection. The results indicate that disease severity can be predicted by analyzing monocyte frequency. Thus, we propose that the frequency of monocytes, can be used to define the severity of the disease as well as the success of the treatment in experimental leishmaniasis.