Modulation of Atlantic salmon miRNome response to sea louse infestation.

MicroRNAs are non-coding RNA that plays a crucial role in post-transcriptional regulation and immune system regulation. On other hand, sea lice are prevalent parasites that affect salmon farming, generating different degrees of immune suppression depending on the salmon and sea louse species. Caligus rogercresseyi for example, which affects the salmon industry in Chile, decreases Th1 response, macrophage activation, TLR-mediated response and iron regulation in infected fish. In this study, we explore Atlantic salmon miRNome during infestation by C. rogercresseyi. Using small RNA sequencing, we annotated 1718 miRNAs for skin and head kidney from infected Atlantic salmon. The most abundant families identified were mir-10, mir-21, mir-30, mir-181 and let7. Significant differences were found between tissue, with 1404 annotated miRNA in head kidney and 529 in skin. Differential analysis of transcript expression indicated that at an early stage of infestation miRNA expression was higher in head kidney than in skin tissue, revealing tissue-specific expression patterns. In parallel, miRNA target prediction using 3'UTRs from highly regulated immune-related genes and iron metabolism showed that mir-140-4 and mir-181a-2-5 modulate the expression of TLR22 and Aminolevulinic acid synthase, respectively. This study contributes knowledge about the immune response of Atlantic salmon during infestation with sea lice.

Seasonal Patterns of Variation in Steroid Plasma Levels and Immune Parameters in Anurans from Brazilian Semiarid Area.

Elevated androgens and glucocorticoids displayed by males during the reproductive season have been proposed to mediate a possible trade-off between reproduction and immunocompetence. Anurans living in arid and semiarid environments display a strong seasonal reproduction, which could accentuate the variation in physiological, immunological, and behavioral parameters. We studied covariation between steroid plasma levels, morphometric variables associated with body condition and immunity, leukocyte profile, parasite load, and response to an immunological challenge across different phases of the annual life-history cycle of three anuran species from a Brazilian semiarid area. Our results showed a seasonal pattern of covariation among leukocyte parameters, kidney mass, and steroid plasma levels, with higher values measured during the reproductive season, particularly when males were sampled during calling activity. Moreover, these anurans showed a stronger response to an immunological challenge during the reproductive period. The immunosuppression during the dry period was particularly evident for the species that aestivate, indicating that the availability of energetic resources might be an important factor determining seasonal variation in inflammatory response. Intensity of the helminth infection was associated with eosinophil count but showed a more complex pattern with regard to androgens levels. These data emphasize that variations in the intensity of helminth infection might be more closely related to specific aspects of the immune response than to the general seasonal patterns of variation in steroid plasma levels, total circulating leukocytes, and inflammatory response.

Resistência contra ectoparasitas em bovinos da raça Crioula Lageana e meio-sangue Angus avaliada em condições naturais / Resistence against ectoparasites in CriouloLageano and crossbred Angus cattle in southern Brazil under natural conditions

Este trabalho foi desenvolvido com o objetivo de avaliar a resistência aos ectoparasitas em bovinos jovens da raça Crioula Lageana e meio-sangue Angus em condições naturais. Foram utilizados 10 machos castrados em cada grupo, recém desmamados (6-8 meses) e mantidos sob as mesmas condições de manejo, em pastagens cultivadas de inverno e verão, no município de Monte Castelo - SC, sofrendo infestação natural por ectoparasitas. A cada 28 dias, fêmeas de carrapatos (Rhipicephalus (Boophilus) microplus) com tamanho acima de 4 mm foram quantificadas nos dois lados do corpo de cada animal, bem como os nódulos com larvas de Dermatobia hominis. A espessura da capa do pelame foi também avaliada a cada coleta e os animais foram classificados quanto à coloração do pelame. Os animais da raça Crioula Lageana foram mais resistentes às infestações por D. hominis e R. microplus. Não houve diferença entre a disposição de carrapatos e bernes conforme os lados direito e esquerdo dos animais. Os animais de pelagem escura albergaram a maior porcentagem de ectoparasitas nos grupos avaliados.(AU)

This study was carried out to evaluate the breed resistance against ectoparasites infestations in Crioula Lageana and crossbred Angus male calves under natural condition. Ten weaned and neutered male calves (6-8 months) of each group were kept together in winter and summer pastures in Monte Castelo, Santa Catarina State. Every 28 days, female ticks (Rhipicephalus (Boophilus) microplus) more than 4 mm long were counted on the right and left side of the body of each animal, as well as the D. hominis nodules. Coat thickness also was measured at each sampling and all animals were classified according coat color. Crioula Lageana group was less infested by D. hominis than crossbred Angus in five times and by ticks in the infestation peak (P<0.05). There were no differences in the distribution of the ticks and grubs between animal body sides. Dark-haired animal in both groups were the most susceptible.(AU)

Resistência contra ectoparasitas em bovinos da raça Crioula Lageana e meio-sangue Angus avaliada em condições naturais / Resistence against ectoparasites in CriouloLageano and crossbred Angus cattle in southern Brazil under natural conditions

Este trabalho foi desenvolvido com o objetivo de avaliar a resistência aos ectoparasitas em bovinos jovens da raça Crioula Lageana e meio-sangue Angus em condições naturais. Foram utilizados 10 machos castrados em cada grupo, recém desmamados (6-8 meses) e mantidos sob as mesmas condições de manejo, em pastagens cultivadas de inverno e verão, no município de Monte Castelo - SC, sofrendo infestação natural por ectoparasitas. A cada 28 dias, fêmeas de carrapatos (Rhipicephalus (Boophilus) microplus) com tamanho acima de 4 mm foram quantificadas nos dois lados do corpo de cada animal, bem como os nódulos com larvas de Dermatobia hominis. A espessura da capa do pelame foi também avaliada a cada coleta e os animais foram classificados quanto à coloração do pelame. Os animais da raça Crioula Lageana foram mais resistentes às infestações por D. hominis e R. microplus. Não houve diferença entre a disposição de carrapatos e bernes conforme os lados direito e esquerdo dos animais. Os animais de pelagem escura albergaram a maior porcentagem de ectoparasitas nos grupos avaliados.

This study was carried out to evaluate the breed resistance against ectoparasites infestations in Crioula Lageana and crossbred Angus male calves under natural condition. Ten weaned and neutered male calves (6-8 months) of each group were kept together in winter and summer pastures in Monte Castelo, Santa Catarina State. Every 28 days, female ticks (Rhipicephalus (Boophilus) microplus) more than 4 mm long were counted on the right and left side of the body of each animal, as well as the D. hominis nodules. Coat thickness also was measured at each sampling and all animals were classified according coat color. Crioula Lageana group was less infested by D. hominis than crossbred Angus in five times and by ticks in the infestation peak (P<0.05). There were no differences in the distribution of the ticks and grubs between animal body sides. Dark-haired animal in both groups were the most susceptible.

Serological survey on Ehrlichia sp. among dogs in the central region of Rio Grande do Sul / Pesquisa sorológica de Ehrlichia sp. em cães da região central do Rio Grande do Sul

A serological survey on Ehrlichia canis was conducted among dogs in the central area of the state of Rio Grande do Sul, where the tick Rhipicephalus sanguineus is a common parasite of dogs. Out of a total of 316 dogs attended at the veterinary teaching hospital in the municipality of Santa Maria, only 14 (4.43%) reacted positively to E. canis antigens in the indirect immunofluorescence assay, with the following endpoint titers: 80 (three dogs), 160 (five), 320 (four), 640 (one) and 1280 (one). Like in previous studies in other regions of the state of Rio Grande do Sul, only a very small portion of the dogs in Santa Maria presented antibodies reactive to E. canis, even though canine infestations due to R. sanguineus are very common in this study region. These results contrast with other regions of Brazil, where E. canis is endemic among canine populations, with seropositivity values generally higher than 30%. Genetic differences among the R. sanguineus populations in South America might be implicated in these contrasting results.(AU)

Foi realizada uma pesquisa sorológica para Ehrlichia canis, em cães, na região central do estado do Rio Grande do Sul, onde o carrapato Rhipicephalus sanguineus é um parasita comum em cães. De um total de 316 cães atendidos no Hospital Veterinário Universitário no Município de Santa Maria, somente 14 (4,43%) reagiram positivamente para o antígeno de E. canis pela reação de imunofluorescência indireta, com os seguintes títulos finais: 80 (3 cães), 160 (5), 320 (4), 640 (1) e 1.280 (1). Semelhante aos estudos anteriores em outras regiões do estado do Rio Grande do Sul, apenas uma pequena parcela dos cães de Santa Maria apresentaram anticorpos reativos para E. canis, mesmo que as infestações caninas por R. sanguineus sejam muito comuns na região de estudo. Esses resultados contrastam com outras regiões do Brasil, nas quais E. canis é endêmica entre a população canina, com valores de soropositividade geralmente superiores a 30%. Diferenças genéticas entre as populações de R. sanguineus, na América do Sul, poderiam estar envolvidas nesses resultados contrastantes.(AU)

Immunosuppressive syndrome in juvenile black-faced ibises (Theristicus melanopis melanopis) in southern Chile.

In the austral summer of 2011, in the rural area of Villarrica county, southern Chile (39 degrees 16'S, 72 degrees 19'W), seven black-faced ibis juveniles (approximately 4 mo old) were observed in the field with weakness; they were unable to follow the group and struggling to take flight. Three of these birds were euthanatized, and complete necropsies were performed. Gross examination showed severe infestation with Colpocephalum trispinum and Ardeicola melanopis lice, moderate emaciation, pale musculature, bursal atrophy, and severe hemorrhagic enteritis due to a heavy proventricular and intestinal infection with Porrocaecum heteropterum nematodes. Fungal pneumonia and severe lymphoid depletion on thymus, spleen, and bursa were diagnosed by microscopic examination. Bursal lesions included apoptosis and necrosis of lymphoid cells, and several cystic follicles. The presence of severe lymphoid depletion associated with fungal pneumonia and severe external and internal parasite infections suggest the presence of an immunosuppressive syndrome in these birds that caused the death of several black-faced ibis juveniles in southern Chile during the summer of 2011.

The involvement of the spleen during chronic phase of Schistosoma mansoni infection in galectin-3-/- mice.

Schistosoma mansoni synthesizes glycoconjugates which interact with galectin-3, eliciting an intense humoral immune response. Moreover, it was demonstrated that galectin-3 regulates B cell differentiation into plasma cells. Splenomegaly is a hallmark event characterized by polyclonal B cell activation and enhancement of antibody production. Here, we investigated whether galectin-3 interferes with spleen organization and B cell compartment during chronic schistosomiasis, using wild type (WT) and galectin-3-/- mice. In chronically-infected galectin-3-/- mice the histological architecture of the spleen, including white and red pulps, was disturbed with heterogeneous lymphoid follicles, an increased number of plasma cells (CD19-B220-/lowCD138+) and a reduced number of macrophages (CD19-B220-Mac-1+CD138-) and B lymphocytes (CD19+B220+/highCD138-), compared with the WT infected mice. In the absence of galectin-3 there was an increase of annexin-V+PI- cells and a major presence of apoptotic cells in spleen compared with WT infected mice. In spleen of WT infected mice galectin-3 was largely expressed in lymphoid follicles and extrafollicular sites. Thus, we propose that galectin-3 plays a role in splenic architecture, controlling distinct events such as apoptosis, macrophage activity, B cell differentiation and plasmacytogenesis in the course of S. mansoni infection.

Kinetics of the inflammatory response in subcutaneous cysticercosis induced in mice by Taenia crassiceps.

The larval stage of Taenia crassiceps has been used to study human cysticercosis as these larvae have antigenic similarity to the cysticerci of Taenia solium. The aim of this study was to evaluate the histopathological and immunological changes that followed the inoculation of T. crassiceps cysticerci into the subcutaneous tissue of C57BL/6 mice. Microscopically, granulomas formed of neutrophils and macrophages developed at the sites of inoculation. The serum concentration of the cytokine interferon (IFN)-γ increased throughout the course of infection, while the serum concentration of interleukin-4 increased during the period of transition from the initial phase (7-30 days postinoculation [dpi]) to the late phase (60-90 dpi) of infection. Destruction of the parasite therefore appears to be associated with an increase in IFN-γ, suggesting that a type 1 immune response is important in the control of the parasite.

Novel gene isolated from Caligus rogercresseyi: a promising target for vaccine development against sea lice.

Sea lice (Copepoda, Caligidae) are the most widely distributed marine pathogens in the salmon industry in the last 30 years. Caligus rogercresseyi is the most important species affecting Chile's salmon industry. Vaccines against caligid copepods have the potential to be a cost-effective means of controlling the infestation and avoid many of the disadvantages of medicine treatments. However, research in the development of such vaccines has begun only recently and approaches used thus far have met with little or no success. In the present study, we characterized a novel gene (denoted as my32) from C. rogercresseyi which has the highest identity with the Lepeophtheirus salmonis gene akirin-2. To assess the function of the gene an RNA interference experiment was developed and a reduction in the number of ectoparasites on fish in the my32-dsRNA treated group was observed. The recombinant my32 protein was used in a vaccination-challenge trial to evaluate its ability to protect against sea lice infestations. A significant reduction in the number of parasites per fish was observed at 24 days post-challenge. These results, together with the delay observed in the development of parasites from the vaccinated group suggest that the major effect of immunization was on the second parasite generation. The results of these experiments suggest that the my32 protein may be a promising target for vaccine development to control sea lice infestations in fish.

The impact of infectious diseases upon neuroendocrine circuits.

During infectious diseases, neuroendocrine and immune networks act in concert, facilitating host response. It is known that infections cause profound immune changes, but the impact upon immunoendocrine circuits has been less studied. Disorders in the hypothalamic-pituitary-adrenal (HPA) axis were frequently observed associated with infections, and these changes often occur in parallel to alterations in the systemic cytokine network. Explanations for the infection-associated immunoendocrine disturbances include several and not mutually exclusive possibilities. Changes in cytokine levels can enhance or suppress the HPA axis, by acting at the hypothalamus-pituitary unit and/or at the adrenal glands. In situ inflammatory reactions or structural changes like vascular alterations or an enhanced extracellular matrix deposition in the endocrine microenvironment may also lead to a transient HPA dysfunction. Lastly, a microbe-related effect by means of pathogen infiltration or exploitation of the host's hormonal microenvironment may be involved as well. A better understanding of the relevance of immunoendocrine communication during infectious diseases, and how disturbances in the flux of information lead to neuroendocrine immune-related disorders will provide important insights into mechanisms underlying the disease pathology.

Specific IgG antibody responses in Oestrus ovis L. (Diptera: Oestridae) infected sheep: associations with intensity of infection and larval development.

Larvae of Oestrus ovis (Diptera: Oestridae) are ubiquitous parasites of nasal and sinusal cavities of sheep and goats. According to the chronobiology of O. ovis infections in Sardinia and the seasonal pattern of the IgG response, the optimal period to investigate the relationships between O. ovis larval populations and intensity of local and systemic IgG antibody responses was mid-July in the summer season. Sarda x Lacaune ewes (n=186), divided into three ram-families were used in the study. Systemic and local IgG responses were measured by ELISA tests using second stage larval crude extracts (L2CE) and L2 (L2SGC) and L3 (L3SGC) salivary gland contents as coating antigens. The number of larval instars, larval length of L1, L2 and L3 larvae, and larval weight of L2 and L3 larvae were individually recorded after ewe necropsy. Negative correlations among larval establishment and/or larval development on the one hand and intensity of local or systemic IgG responses on the other hand were found in two out of three studied ram-families.

[Pharmacologically immunosuppressed mice as a model for study of opportunistic parasite infections]. / Camundongos imunossuprimidos farmacologiamente como modelo para estudo de infecções parasitárias oportunistas.

Immunodeficient animals are important research models for studies in parasitology, oncology and immunology. Immunosuppressive drugs have been experimentally used to obtain a state of immunodeficiency in mice. This investigation aimed to quantify the circulating T and B cells of mice treated with the immunosuppressive agents dexamethasone (Dx), cyclosporine (CsA) and cyclophosphamide (CY), as well as to observe the behaviour of lymphocytic populations in the spleen of these animals. Blood samples were collected for counting the total peripheral blood leukocytes and T and B lymphocytes using flow cytometry. Total leukocytes of mice treated with the three drugs during all study showed a significant decrease when compared to the results of the control group. The proportion of B and T lymphocytes from the treated animals also decreased significantly. Spleen sections revealed a moderate decrease in the cellularity of the white pulp and the development of lymphocyte apoptosis in mice from groups treated with CY and Dx. Results showed that the proposed experimental models demonstrated to be suitable for studies of murine immunodeficiency.

Regulatory role of Toll-like receptor 2 during infection with Trypanosoma cruzi.

Previous studies have emphasized the role of Toll-like receptors (TLRs) and myeloid differentiation factor 88 (MyD88) during infection with protozoan parasites. TLR2 was shown to be important for induction of cytokine synthesis by macrophages exposed to the purified glycosylphosphatidylinositol (GPI)-anchored mucin-like glycoproteins of Trypanosoma cruzi trypomastigotes (tGPIm). On the other hand, MyD88(-/-) mice, but not TLR2(-/-) mice, showed impaired cytokine production and resistance to infection with T. cruzi parasites. Here we evaluate the importance of MyD88 and TLR2 in MAPK activation and cytokine synthesis by macrophages exposed to live T. cruzi parasites and compared to tGPIm. The absence of MAPK phosphorylation in TLR2- and MyD88-deficient macrophages exposed to tGPIm correlated with the incapacity to induce cytokine release in these cells. In contrast, activation of MAPK and synthesis of pro-inflammatory cytokines were not abrogated in TLR2-deficient macrophages exposed to live T. cruzi parasites. We also showed that pretreatment with tGPIm significantly reduces cytokine release by macrophages in response to T. cruzi in a TLR2-dependent manner. Consistently, TLR2(-/-) mice were shown to produce enhanced levels of cytokines upon in vivo challenge with T. cruzi parasites. Together, these results suggest the involvement of additional TLR(s) in the pro-inflammatory response of macrophages to whole parasites, and that, in vivo, TLR2 may have a predominant immunoregulatory role during acute infection with T. cruzi parasites.