Influence of serum progesterone levels on the inflammatory response of female dogs with visceral leishmaniosis.

The aim of this study was to evaluate the histopathological changes to the mammary gland that occur in female dogs with visceral leishmaniosis and to correlate the findings with the parasite load, inflammatory cell profile in mammary tissue and serum progesterone levels. For this, 20 adult female dogs that were naturally infected with Leishmania infantum, not spayed, not pregnant and free from mammary tumors were used. They were divided into two groups: G1 (n = 9) with high serum progesterone levels and G2 (n = 11) with low serum progesterone levels. The parasite load and the immunophenotype of leukocytes infiltrated into the mammary tissue (CD3, CD4, CD8 and MCA874) were evaluated using the immunohistochemical technique. In the mammary gland, chronic inflammatory infiltrate was mainly found in G1, sometimes associated with granulomatous inflammation, higher parasite load and higher density of cells immunolabeled for CD3, CD4, CD8 and MCA874. A significant positive correlation (p < 0.05) was observed between the parasite load and the immunolabeled leukocytes. The influence of the serum progesterone level in the mammary gland of infected female dogs can contribute to the maintenance of an immunosuppressive cell profile and favor the persistence of the parasite in this site.

Co-infections by Mycoplasma hyopneumoniae, Mycoplasma hyorhinis and Mycoplasma flocculare in macroscopic lesions of lung consolidation of pigs at slaughter.

Infections with Mycoplasma hyopneumoniae (Mhyo), Mycoplasma hyorhinis (Mhr) and Mycoplasma flocculare (Mfloc) are common in swine. However, the degree of co-infections and the correlations between these mycoplasma co-infection and the severity of macroscopic lung consolidation lesions (MLCL) have not yet been explored in Brazil.The objectives were to quantify Mhyo, Mhr, and Mfloc in MLCL of slaughter pigs in Brazil, and to assess correlations with the degree of MLCL in slaughter pigs. To this end, five groups of lungs were made based on severity of lung lesions, and 80 lungs were collected for each group (400 lungs in total). The Mycoplasmas were quantified using a multiplex qPCR. Statistical differences and comparison between the groups were evaluated, respectively, by the Kruskal-Wallis test (p < 0.05) and Dunn's test (p < 0.05), and the correlation between the data was performed by Spearman's method (p < 0.05). The results revealed that the extent of MLCL showed a positive correlation with the Mhyo estimate (rho = 0.26; p < 0.05), a negative correlation with the Mfloc estimate (rho= -0.15; p < 0.05), and no significant correlation with the Mhr estimate (p = 0, 12). The extension of MLCL showed a positive correlation with the co-infection by Mfloc and Mhr (rho = 0.17; p < 0.05), and no significant correlation with Mhyo and Mhr (p = 0.87), and a negative correlation with Mhyo and Mfloc (rho= -0.28; p < 0.05). This study allowed to infer that, regarding the extension of MLCL, Mhr and Mfloc did not present opportunistic activity in relation to primary infection by Mhyo, but revealed some potential aggravation of these lesions. In addition, Mhyo expressed inhibitory behavior towards Mfloc, suggesting that one can compete with the other's presence.

Expression of matrix metalloproteinase-2 and metalloproteinase-9 in the skin of dogs with visceral leishmaniasis.

The skin is the first organ to be infected by the parasite in canine visceral leishmaniasis. The enzyme matrix metalloproteinase (MMP) acts towards degradation of the extracellular matrix (ECM) and modulation of the inflammatory response against many kinds of injuries. The aims of this study were to evaluate the expression of MMP-2 and MMP-9 through immunohistochemistry and zymography on the skin (muzzle, ears, and abdomen) of dogs that were naturally infected by Leishmania spp. and to compare these results with immunodetection of the parasite and with alterations to the dermal ECM. Picrosirius red staining was used to differentiate collagen types I and III in three regions of the skin. The parasite load, intensity of inflammation, and production of MMP-2 (latent) and MMP-9 (active and latent) were higher in the ear and muzzle regions. MMP-9 (active) predominated in the infected group of dogs and its production was significantly different to that of the control group. Macrophages, lymphocytes, and plasma cells predominated in the dermal inflammation and formed granulomas in association with degradation of mature collagen (type I) and with discrete deposition of young collagen (type III). This dermal change was more pronounced in dogs with high parasite load in the skin. Therefore, it was concluded that the greater parasite load and intensity of inflammation in the skin led consequently to increased degradation of mature collagen, caused by increased production of MMPs, particularly active MMP-9, in dogs with visceral leishmaniasis. This host response profile possibly favors systemic dissemination of the parasite.

Morphological changes in the bone marrow of the dogs with visceral leishmaniasis.

The aim of this study was to evaluate the most frequent lesions in the bone marrow of dogs naturally infected by Leishmania (Leishmania) chagasi. Thirty-three dogs sacrificed at the Zoonosis Control Center of Araçatuba, a municipality endemic for visceral leishmaniasis (VL), were used. The animals were classified as asymptomatic, oligosymptomatic, and symptomatic groups. At the necropsy, bone marrow samples were collected from the femur, fixed, processed, and stained with hematoxylin and eosin. The lesion intensity was classified as mild, moderate, or severe. The parasite load was determined using immunohistochemistry. The most important lesions consisted of multifocal to diffuse granulomas, megakaryocytic dysplasia, and medullary aplasia. There were no statistical differences between the three clinical groups regarding parasite load and lesion intensity. Asymptomatic dogs also presented high parasitism in the bone marrow as dogs with clinical signs of VL. It was concluded that, regardless of clinical group, the bone marrow is a site for multiplication of Leishmania chagasi. Possibly, the bone marrow dysplasia may arise from the presence of many parasitized and activated macrophages in this organ. Consequently, it affects the profile of hematopoietic cells in the bone marrow and systemic circulation.