Aleksandro Schafer da Silva

Universidade do Estado de Santa Catarina, Joinville, Santa Catarina, Brazil

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Publications (88)50.72 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To verify the trypanocidal effectiveness of aescin and aescin liposomes against Trypanosoma evansi in vitro and in vivo.
    Asian Pacific Journal of Tropical Biomedicine 12/2014; DOI:10.12980/APJTB.4.2014APJTB-2014-0435
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    ABSTRACT: Neosporosis is an infectious disease caused by the parasite Neospora caninum. Knowledge regarding neosporosis in goats is still quite limited, especially in the state of Santa Catarina (SC), southern Brazil. Therefore, this study aimed to assess the seroprevalence and risk factors for N. caninum in goats in the western and mountain regions of SC. Blood samples were collected from 654 goats in 57 municipalities. The indirect immunofluorescence test was used for antibody detection against N. caninum. Thirty samples (4.58%) were seropositive, with titers ranging from 1:50 to 1:6400. An epidemiological survey was also conducted in order to identify risk factors for neosporosis in goats. It was found that reproductive problems on the farms, as well as the diet and direct contact with dogs were casual risks for neosporosis. These results indicate that N. caninum infects goats in these regions, which may lead to reproductive problems.
    Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 09/2014; 23(3):360-366. DOI:10.1590/S1984-29612014062 · 0.96 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the biochem-ical variables in newborn lambs of an extensive rearing sys-tem. In this study, 30 multiparous ewes, with simple parturi-tion, and their 30 lambs were used. Blood samples were drawn from the ewes (on days 1, 5, and 10 postpartum) and lambs (before ingestion of colostrum, and on days 1, 5, and 10 postpartum), in order to measure the serum variables related to lipid and protein metabolism (total protein, albumin, glob-ulin, urea, triglycerides, and cholesterol). Ewe's blood levels of total protein, albumin, globulin, and urea did not differ throughout the evaluated periods (P>0.05). However, on day 1 postpartum, the levels of triglyceride were higher than on day 10, while the cholesterol levels decreased progressive-ly, following the evaluation periods (P<0.05). In lamb's sam-ples, the levels of total proteins, albumin and globulin were higher on day 10, when compared with the other periods (P<0.05). Unlike, serum levels of urea, triglycerides and cholesterol were higher on the first day of life, when compared with the levels before the ingestion of colostrum and with the fifth and tenth days (P<0.05). Therefore, our results allowed to conclude that on the first day of life (for lambs) and in postpartum (for ewes), there occurred a fluctuations of biochemical variables, mainly related to lipid and protein metabolism. These variations may be related to the ingestion of colostrum and/or milk in lambs, and hormonal changes in ewes.
    Comparative Clinical Pathology 08/2014; 24(2). DOI:10.1007/s00580-014-1992-9
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    ABSTRACT: The aim of this study was to verify the trypanocidal effectiveness of aqueous, methanolic, and ethanolic extracts of Achyrocline satureioides against Trypanosoma evansi in vitro. A. satureioides extracts, known as macela, were used on trypomastigotes at different concentrations (1, 5, 10, 50, 100, 500, and 1,000 µg/ml) and exposure times (0, 1, 3, 6, and 9 hr). A dose-dependent effect was observed when the 3 extracts were tested. The concentrations of 1, 5, and 10 µg/ml were not able to kill trypomastigotes until 3 hr after exposure, and the highest concentrations (500 and 1,000 µg/ml) were able to kill all trypomastigotes after 1 hr. When the time of exposure was increased up to 9 hr, the concentrations at 50 and 100 µg/ml were 100% effective to 3 extracts. The chemical analysis of the extracts revealed the presence of flavonoids, a trypanocidal compound already described. Based on the results, we can conclude that the A. satureioides extracts exhibit trypanocidal effects.
    The Korean Journal of Parasitology 06/2014; 52(3):311-5. DOI:10.3347/kjp.2014.52.3.311 · 0.97 Impact Factor
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    ABSTRACT: This study aims to investigate the occurrence of gastrointestinal parasites in goats from the Western Santa Catarina, Brazil. Twenty four farms were analyzed in 17 different municipalities. Animals (n=217) from different production purposes (milk and meat) and age were randomly chosen. Fecal samples were collected from the rectum stored in plastic bottles and transported to the laboratory in portable coolers at 10 °C. The technique of centrifugal flotation with saturated sugar solution was carried out in order to investigate the presence of eggs, cysts, and oocysts of gastrointestinal parasites. In 88.9% of the investigated animals, it was observed that the presence of nematode eggs which belongs to the Strongylida order, after cultivation and larvae identification were identified as Haemonchus spp., Trichostrongylus spp., Teladorsagia spp., Cooperia spp., and Oesophagostomum spp. Eggs of Thysanosoma, Trichuris, Moniezia, and Neoascaris genus were also observed. Additionally, the presence of oocysts of Eimeria spp. and Cryptosporidium spp. as well as cysts of Giardia spp., and Entamoeba spp. were verified. In all the farms evaluated, the animals showed a single or mixed infection, with the highest occurrence of helminths belonging to the Haemonchus and Trichostrongylus genus, as well as the protozoan Eimeria.
    Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 03/2014; 23(1):101-4. DOI:10.1590/S1984-29612014016 · 0.96 Impact Factor
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    ABSTRACT: SUMMARY This study aimed to develop and test the in vitro and in vivo effectiveness of diminazene aceturate encapsulated into liposomes (L-DMZ) on Trypanosoma evansi. To validate the in vitro tests with L-DMZ, the efficacy of a commercial formulation of diminazene aceturate (C-DMZ) was also assessed. The tests were carried out in culture medium for T. evansi, at concentrations of 0·25, 0·5, 1, 2 and 3 μg mL-1 of L-DMZ and C-DMZ. A dose-dependent effect was observed for both formulations (L-DMZ and C-DMZ), with the highest dose-dependent mortality of trypomastigotes being observed at 1 and 3 h after the onset of tests with L-DMZ. The results of in vivo tests showed the same effects in the animals treated with L-DMZ and C-DMZ in single doses of 3·5 mg kg-1 and for 5 consecutive days (3·5 mg kg-1 day-1). It was possible to conclude that T. evansi showed greater in vitro susceptibility to L-DMZ when compared with C-DMZ. In vivo tests suggest that treatment with the L-DMZ and C-DMZ showed similar efficacy in vivo. The potential of the formulation developed in this study was clearly demonstrated, as it increased the efficacy of the treatment against trypanosomosis, but more studies are needed to increase the effectiveness in vivo.
    Parasitology 01/2014; 141(6):1-9. DOI:10.1017/S0031182013002114 · 2.35 Impact Factor
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    ABSTRACT: Parasitic diseases affecting goats are able to cause major economic losses, standing out, among them, the lice infestation. According to the literature, lice can act as vectors of other diseases, including the ones caused by blood protozoan. In this sense, this survey study aimed to assess the ectoparasites of goats in the west region of Santa Catarina (SC). Two hundred seventeen goats from 24 different rural properties located in 17 towns in SC were examined. From them, ectoparasites were collected and evaluated in laboratory, where the parasitological classification was performed. In 13 properties, it was possible to identify ectoparasites. Damalinia caprae lice were observed in 126 animals (58 %), while Linognathus stenopsis were found in 10 animals (4.6 %). It is noteworthy that, in these properties, all the animals were under lice parasitism, independent of sex or age. The goats had peeling skin, particularly in the back region (lumbar). All of the 24 properties evaluated were reported having problems with lice in different seasons of the year, even under regular treatment with cypermethrin (spraying). Based on our findings, it was possible to conclude that D. caprae is the major ectoparasite of goats in the investigated area.
    Comparative Clinical Pathology 01/2014; 23(2). DOI:10.1007/s00580-013-1860-z
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    ABSTRACT: The aim of this study was to evaluate nitric oxide levels, oxidants and antioxidant levels in multiparous ewes with simple parturition and their respective newborns on an extensive rearing system. Blood samples were drawn from ewes (n = 30) and their respective lambs (n = 30) on days 1, 5, and 10 postpartum in order to measure nitrate/nitrite (NOx) seric levels, total oxidation status (TOS), total antioxidant capacity (TAC), and ferric reducing ability of plasma (FRAP) through biochemical techniques using anautomatic analyzer. NOx levels in lambs significantly increased on days 5 and 10 compared to day 1 postpartum (P < 0.05), reaching higher levels in lambs when compared to ewes (P < 0.05). The TOS postpartum levels did not differ in ewes (P > 0.05). In addition, TOS levels in lambs were higher (P < 0.05) than in their mothers at day 1 postpartum. The TAC levels in mothers and lambs did not differ between day 1 and 5 postpartum (P > 0.05), but the lambs showed a reduction on day 10 compared to their mothers on the same day (P < 0.05). The FRAP levels in ewes was higher on day 10 postpartum when compared to days 1 and 5 (P < 0.05). In lambs, the FRAP levels were not different (P > 0.05), but were superior to those measured in the mothers on days 1 and 5 postpartum (P < 0.05). Based on these results, we conclude that ewes and lambs respond differently to the nitric oxide, oxidant, and antioxidant metabolism at postpartum. These alterations are important for lamb survival and development.
    Small Ruminant Research 01/2014; DOI:10.1016/j.smallrumres.2014.09.010 · 1.10 Impact Factor
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    ABSTRACT: Rhipicephalus (Boophilus) microplus is a natural parasite of cattle, with rare reports of parasitism in horses. Therefore, the aim of this study is to report a rare case of high infestation by R. (B.) microplus in a mare in the town of Riqueza, state of Santa Catarina, Southern Brazil. In December 2012, in a farm with 12 horses in its herd, a single mare was highly infected, showing clinical signs such as pale to pink mucous membranes and bleeding in the neck, the main place in her body where the ticks were fixed. The horse was treated through the use of a spray with a drug association of cypermethrin, chlorpyrifos, and citronellal (Colosso®), showing temporary effectiveness, since 15 days posttreatment immature forms (larvae and nymphs) of ticks were again found. Therefore, this mare has high susceptibility to parasitism by R. (B.) microplus, differently from the other horses at the same farm that were not parasitized by this mite.
    Comparative Clinical Pathology 11/2013; DOI:10.1007/s00580-013-1787-4
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    ABSTRACT: Abstract Clinostomum complanatum is a zoonotic parasite of birds, and its larval form (metacercariae) may cause disease in fish. The immune response of fish infected by C. complanatum is unknown, and therefore the objective of this study was to evaluate serum levels of pro-inflammatory cytokines in silver catfish (Rhamdia quelen) infected by this parasite. The analysis showed that fish infected with metacercariae presented significantly (P<0.05) higher levels of tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), and interleukin 6 (IL-6) when compared to those not-infected. These data suggest that C. complanatum larvae activate the host immune response.
    Journal of Parasitology 09/2013; DOI:10.1645/13-300.1 · 1.26 Impact Factor
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    ABSTRACT: The lesser mealworm, Alphitobius diaperinus (Panzer), is an insect that lives in poultry houses, and high infestations may cause economic losses to producers. The control of this insect is usually done with insecticides; however, many of these chemicals have no effect on lesser mealworm. Therefore, control alternatives are needed. The aim of this study was to evaluate the influence of Cunila angustifolia (Benth) oil on larvae and adults of A. diaperinus. In vitro tests used larvae and adults of A. diaperinus distributed in petri dishes with 0, 1, 5, and 10% of oil in a single dose. In vivo tests were performed in poultry houses with five treatments: 0, 5, and 10% and chemical insecticide (cypermethrin) in a single application, and a group with 5% of oil applied twice 15 d apart. In vitro, oil bioactivity showed an efficacy of 100% both for larvae and adults, when tested at concentrations of 5 and 10%. A reduced number of larvae were observed using 1% of oil; however, it was not effective against adults as compared with the control group. In vivo, the oil effectiveness against lesser mealworm was verified by larva and adult reduction in all concentrations compared with control (0%) throughout the experiments, with better efficacy when used at 5% with two applications. Therefore, we concluded that the oil of C. angustifolia has larvicidal and insecticidal effect against A. diaperinus larvae and adults, in vitro and in vivo.
    Journal of Medical Entomology 09/2013; 50(5):1040-5. DOI:10.1603/ME12277 · 1.82 Impact Factor
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    ABSTRACT: Several studies have shown the mechanisms and importance of immune responses against Toxoplasma gondii infection and the notable role of cholinesterases in inflammatory reactions. However, the association between those factors has not yet been investigated. Therefore, the aim of this study was to evaluate the acetylcholinesterase (AChE) activity in blood and lymphocytes and the activity of butyrylcholinesterase (BChE) in serum of rats experimentally infected with T. gondii during the acute phase of infection. For that, an in vivo study was performed with evaluations of AChE and BChE activities on days 5 and 10 post-infection (PI). The activity of AChE in blood was increased on day 5 PI, while in lymphocytes its activity was enhanced on days 5 and 10 PI (P<0.05). No significant difference was observed between groups regarding to the activity of BChE in serum. A positive (P<0.01) correlation was observed between AChE activity and number of lymphocytes. The role of AChE as an inflammatory marker is well known in different pathologies; thus, our results lead to the hypothesis that AChE has an important role in modulation of early immune responses against T. gondii infection.
    The Korean Journal of Parasitology 08/2013; 51(4):421-6. DOI:10.3347/kjp.2013.51.4.421 · 0.97 Impact Factor
  • Aleksandro Schafer Da Silva, Alexandre Alberto Tonin, Leandro Sâmia Lopes
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    ABSTRACT: The aim of this study is to report an outbreak of lice (Bovicola equi) in horses in southern Brazil, focusing on epidemiology, diagnosis, and treatment. Twenty-three horses in a stud farm presented with intense itching, crusted lesions, focal alopecia, and scaly skin. The outbreak occurred during the winter and probably due to the absence of sanitary barriers on the property. The diagnosis was carried out based on clinical signs associated with macroscopic and microscopic visualization of lice identified as B. equi. The treatment was performed with a single dose of Fipronil (Topline® Merial Brasil, Campinas, São Paulo, Brazil) spray (0.5%), eliminating immature and adult stages of lice. The clinical signs caused by the lice in horses disappeared few days after treatment.
    Journal of Equine Veterinary Science 07/2013; 33(7):530-532. DOI:10.1016/j.jevs.2012.08.003 · 0.89 Impact Factor
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    ABSTRACT: The aim of this study was to characterize the response of acute phase proteins (APP) in rabbits experimentally infected with Trypanosoma evansi (T. evansi), and to relate the findings with serum immunoglobulins levels, in order to verify the relation between APP and the immune response of rabbits. A total of 12 animals were used in this experiment and divided into 2 groups, control and infected, of six rabbits each. The experimental period was 118days, and blood was collected on days 0, 5, 20, 35, 65, 95 and 118 post-infection (PI). The infection with T. evansi stimulated APP and immunoglobulins production, once the infected animals showed an increase in C-reactive protein, haptoglobin, alpha 2-macroglobulin and IgM levels. The elevation in IgM levels observed in this study, when related to the increase in C-reactive protein and haptoglobin levels, suggests the involvement of these proteins in host defense against flagellated protozoa, with possible participation in the control of the parasitemia in rabbits infected with T. evansi.
    Research in Veterinary Science 02/2013; 95(1). DOI:10.1016/j.rvsc.2013.01.029 · 1.51 Impact Factor
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    ABSTRACT: This study aimed to verify the occurrence of antibodies against Toxoplasma gondii in rheas (Rhea americana) and ostriches (Struthio camelus) commercially breeding in Brazil. Blood samples from 20 rheas and 46 ostriches (young and adults) were serologically tested using a technique known as modified agglutination test (MAT) at an initial titration of 1:16 for ostriches and 1:25 for rheas. Antibodies against T. gondii were found in 50% (10/20) of the rheas, with titers ranging from 1:25 to 1:6,400. The incidence of antibodies against T. gondii in ostriches was 17.4% (8/46) with titers ranging from 1:16 to 1:256. Birds showing titers higher than 1:200 for T. gondii were mainly the young ones. Therefore, rheas and ostriches may be parasitized by T. gondii, showing high levels of antibodies against this parasite.
    Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 01/2013; 22(3):437-9. DOI:10.1590/S1984-29612013000300021 · 0.96 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate biochemical parameters of iron metabolism in rats experimentally infected with T. evansi. To this end, 20 rats (Wistar) were intraperitoneally inoculated with blood containing trypomastigotes 10(6) (Group T) and 12 animals were used as negative control (Group C) and received saline (0.2 mL) through same route. Blood samples were collected by cardiac puncture on day 5 (C5, T5) and 30 (C30, T30) post-inoculation (pi) to perform complete blood count and determination of serum iron, transferrin, ferritin, total and latent iron fixation capacity, transferrin saturation and prohepcidin concentration. Also, bone marrow samples were collected, to perform Pearls staining reaction. Levels of iron, total and latent iron binding capacity and prohepcidin concentration were lower (P <0.05) in infected rats (T5 and T30 groups) compared to controls. On the other hand, levels of transferrin and ferritin were higher when compared to controls (P <0.05). The transferrin saturation increased on day 5 pi, but decreased on day 30 pi. The Pearls reaction showed a higher accumulation of iron in the bone marrow of infected animals in day 5 pi (P <0.01). Infection with T. evansi in rats caused anemia and changes in iron metabolism associated to the peaks of parasitemia. These results suggest that changes in iron metabolism may be related to the host immune response to infection and anemic status of infected animals.
    Experimental Parasitology 12/2012; 133(3). DOI:10.1016/j.exppara.2012.12.010 · 1.86 Impact Factor
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    ABSTRACT: Abstract Lice infestations are commonly seen in buffaloes, causing damage directly to the animal, i.e., itching, skin lesions, and anemia; in addition, these insects can also be vectors for infectious diseases. The present study describes an outbreak of lice in buffaloes, as well as an evidence for Haematopinus tuberculatus acting as a vector of anaplasmosis. Lice and blood were collected from 4 young buffaloes (2- to 4-mo-old); a molecular analysis for the presence of Anaplasma marginale was conducted. DNA of A. marginale was detected in the blood of all 4 animals. Twelve lice were collected and separated in 4 groups with 3 insects each, to comprise a pool of samples. After DNA extraction and molecular analysis, a positive PCR for A. marginale was found in all pooled samples. These results identify sucking lice as potential vectors of anaplasmosis. However, additional studies are necessary to fully evaluate the vector potential of H. tuberculatus for A. maginale transmission.
    Journal of Parasitology 10/2012; 99(3). DOI:10.1645/GE-3260.1 · 1.26 Impact Factor
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    ABSTRACT: Rangeliosis is a hemoparasitosis that affects dogs in Brazil. The disease has similar clinical and pathological characteristics to other hemo-protozoan infections. So, this paper has aimed to report a clinical case of infection by Rangelia vitalii in one dog, focusing on the need for the differential diagnosis to other infectious diseases. The animal showed apathy, anemia, thrombocytopenia, alteration of leucogram, and bleeding. The first difference was the observation of parasites in blood smears, where R. vitalii was visualized within leukocytes and erythrocytes. The confirmation of the clinical diagnosis was made by molecular test to R. vitalii. The dog was debilitated, and died a few hours after treatment at the veterinary hospital. At necropsy, splenomegaly, lymphadenopathy, and mild jaundice in the abdominal viscera were found. This article draws attention to the need for the parasitological, serological, and molecular to differential diagnosis in order to differentiate from other clinically similar disorders.
    Parasitology Research 10/2012; DOI:10.1007/s00436-012-3160-y · 2.33 Impact Factor
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    ABSTRACT: Rangelia vitalii is a protozoon that causes diseases in dogs, and anemia is the most common laboratory finding. However, few studies on the biochemical changes in dogs infected with this protozoon exist. Thus, this study aimed to investigate the biochemical changes in dogs experimentally infected with R. vitalii, during the acute phase of the infection. For this study, 12 female dogs (aged 6-12 months and weighing between 4 and 7 kg) were used, divided in two groups. Group A was composed of healthy dogs (n = 5); and group B consisted of infected animals (n = 7). Blood samples were collected on days 0, 10, 20 and 30 after infection, using tubes without anticoagulant to obtain serum and analyze the biochemical parameters. An increase in alanine aminotransferase (ALT) on day 20 (P < 0.05) was observed. Also, increased creatine kinase (CK) and aspartate aminotransferase (AST) levels were observed throughout the experimental period (P < 0.05). No changes in the serum gamma-glutamyltransferase, urea and creatinine levels were observed. Thus, is possible to conclude that experimental infection with R. vitalii in dogs causes changes to the biochemical profile, with increased ALT, AST and CK enzyme levels.
    Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 09/2012; 21(3):243-8. DOI:10.1590/S1984-29612012000300012 · 0.96 Impact Factor
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    ABSTRACT: This study aimed to test an alternative protocol with human plasma to control Trypanosoma evansi infection in mice. Plasma from an apparently 27-year-old healthy male, blood type A+, was used in the study. A concentration of 100 mg.dL(-1) apolipoprotein L1 (APOL1) was detected in the plasma. Forty mice were divided into four groups with 10 animals each. Group A comprised uninfected animals. Mice from groups B, C and D were inoculated with a T. evansi isolate. Group B was used as a positive control. At three days post-infection (DPI), the mice were administered intraperitoneally with human plasma. A single dose of 0.2 mL plasma was given to those in group C. The mice from group D were administered five doses of 0.2 mL plasma with a 24 hours interval between the doses. Group B showed high increasing parasitemia that led to their death within 5 DPI. Both treatments eliminated parasites from the blood and increased the longevity of animals. An efficacy of 50 (group C) and 80% (group D) of human plasma trypanocidal activity was found using PCR. This therapeutic success was likely achieved in the group D due to their higher levels of APOL1 compared with group C.
    Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 03/2012; 21(1):55-9. DOI:10.1590/S1984-29612012000100011 · 0.96 Impact Factor

Publication Stats

236 Citations
50.72 Total Impact Points

Institutions

  • 2012–2014
    • Universidade do Estado de Santa Catarina
      Joinville, Santa Catarina, Brazil
  • 2006–2013
    • Universidade Federal de Santa Maria
      • Department of Microbiology and Parasitology
      Santa Maria da Boca do Monte, Rio Grande do Sul, Brazil
  • 2010
    • Universidade Federal do Rio Grande do Sul
      Pôrto de São Francisco dos Casaes, Rio Grande do Sul, Brazil