Aleksandro Schafer da Silva

Universidade Federal de Santa Maria, Santa Maria da Boca do Monte, Rio Grande do Sul, Brazil

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Publications (67)37.43 Total impact

  • [show abstract] [hide abstract]
    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. · 0.72 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; · 2.36 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. · 1.86 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. · 0.88 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; · 1.77 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; · 2.15 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; · 2.85 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. · 0.72 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. · 0.72 Impact Factor
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    ABSTRACT: Cryopreservation is a method of keeping parasites alive in a laboratory. However, this technique may also damage the parasite. Alternatively, parasites may be maintained by in vitro culture. Unfortunately, for Trypanosoma evansi no effective medium that is able to maintain the parasite for more than 4 months has been described. In this study, we examined the effect of purifying trypomastigote through DEAE-cellulose chromatography before and after cryopreservation, by analyzing the pre-patent period, longevity, parasitemia, and count of viable parasites. Our results showed a three-times increase in the concentration of viable trypomastigote in DEAE-purified cryopreserved parasites as compared to non-DEAE-purified cryopreserved parasites. This indicates that DEAE-cellulose chromatography followed by cryopreservation is an effective method for the storage and preservation of T. evansi, with the advantage that the stocked parasites will be ready to use in molecular biology procedures.
    Research in Veterinary Science 04/2011; 90(2):257-9. · 1.77 Impact Factor
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    ABSTRACT: One of the main characteristics of the trypanosomosis is the development of anemia, although its pathogenesis still remains unclear. Therefore, the objective of this study was to discuss the possible pathogenesis of anemia in the infection by Trypanosoma evansi in cats. A study using an experimental model with T. evansi-infected cats reported changes in serum iron levels, alterations in the activity of enzymes of the cholinergic system, and oxidative stress correlated to normocytic, normochromic, and regenerative anemia. During this article, the aforementioned parameters will be simultaneously analyzed and related to hematological parameters that determine anemia in cats infected with this protozoan. KeywordsAcetylcholinesterase–Anemia–Iron–Lipid peroxidation
    Comparative Clinical Pathology 01/2011; 20(4):393-396.
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    ABSTRACT: The aim of this study was to evaluate the fungal microflora present in drinking water and domestic sewage from different districts of Santa Maria, Rio Grande do Sul, Brazil. Water and sewage samples were collected during the four seasons and analyzed by the technique of Colony Forming Units (CFU). Yeasts and fungi of the genera Penicillium and Aspergillus were observed in the water samples. The genus Geotrichum was also found in the sewage. Therefore, it is concluded that treatment of water held in the municipality is unable to remove these agents. objetivo deste estudo foi investigar a microbiota fúngica presente na água potável e no esgoto doméstico de distintos bairros de Santa Maria, Rio Grande do Sul, Brasil. Amostras de água e esgoto foram colhidas durante as quatro estações do ano e analisadas pela técnica de Unidades Formadoras de Colônias (UFC). Foi observada a presença dos gêneros Penicillium, Aspergillus e leveduras nas amostras de água. No esgoto, além dos agentes fúngicos reportados na água foi identificado o gênero Geotrichum. Dessa forma, conclui-se que o tratamento da água realizado no município não é capaz de eliminar estes agentes.
    Semina : Ciências Agrárias. 01/2011;
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    ABSTRACT: Oxidative stress (OS) is defined as an imbalance in the production of reactive oxygen species and the capacity of antioxidant defenses. The objective of this work was to investigate OS and antioxidant capacity in pregnant women. Parameters of the oxidative status and antioxidant capacity in serum and whole blood were evaluated in thirty-nine women with normal pregnancy. The assessment of antioxidants indicated an increase in superoxide dismutase and catalase activities (P<0.05 and P<0.01) and a decrease in ascorbic acid levels and the total content of sulfhydryl (P<0.05 and P<0.001). Additionally, when the pro-oxidant system was investigated we found an increase (P<0.01) in malondialdehyde and no significant change (P>0.05) in protein carbonylation. This study demonstrates that there is a change in the pro-oxidant and antioxidant defenses associated with body and circulation changes that are inherent to the pregnancy process.
    Redox report: communications in free radical research 01/2011; 16(6):230-6. · 1.51 Impact Factor
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    ABSTRACT: This study was aimed at evaluating the electrophoretic profile of serum proteins in Trypanosoma evansi-infected cats during different periods of infection. Thirteen adult females non-breeding Felis catus were separated into two groups. Animals from the infected group (n=7) were inoculated intraperitoneally with a strain of T. evansi; whereas, animals from the control group (n=6) received a physiological solution. Blood samples were collected at days 0, 7, 21, and 35 for total protein evaluation and protein fractionation by electrophoresis. Albumin (P<0.01), alpha-2 globulin and gamma globulin (P<0.05) concentrations were statistically different from the seventh day post-inoculation onwards. Beta-globulin levels were increased from day 21 onwards (P<0.05). Alpha-1 globulin fraction did not differ statistically. These results indicate that the infection by T. evansi in cats alters the serum protein electrophoretic profile.
    Preventive Veterinary Medicine 05/2010; 95(3-4):301-4. · 2.39 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the gastrointestinal parasitism in Cavia aperea aperea (cavy), captured in the central region of Rio Grande do Sul State. Fecal samples from five free-living cavies were collected for research of parasites. Samples were analyzed by the centrifugal-flotation method with zinc sulfate and parasites were identified microscopically based on (oo)cyst and egg size and morphology. Cysts of Giardia sp. and (oo)cysts of Cryptosporidium sp. and Cystoisospora sp. were observed in one or more cavies. Eggs of Paraspidodera uncinata were observed in three of the five rodents. All infected animals showed mild infection by parasite. This is the first report of Giardia sp., Cryptosporidium sp. and Cystoisospora sp. in Cavia a. aperea.
    Research in Veterinary Science 03/2010; 89(2):206-8. · 1.77 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate cholinesterase activity during the early acute phase of Trypanosoma evansi infection in rats. Fifteen male Wistar rats were randomly distributed into three groups (n=5 animals per group): two trypanosome-infected groups (T3 and T5) and uninfected controls (C). The animals were inoculated intraperitoneally with 10(6) trypanosomes. The blood was collected by cardiac puncture on the 3rd (T3) or 5th day post-infection (T5 and C). Cerebrum and cerebellum were removed for the evaluation of acetylcholinesterase (AChE) activity. AChE activity was also evaluated in whole blood and butyrylcholinesterase activity (BUChE) in plasma samples. Parasitemia were progressive increase and parasites were observed in the peripheral blood of all infected animals one day post-inoculation. AChE activity was not altered in cerebrum and cerebellum tissues. AChE activity in blood significantly decreased in the T3 and T5 groups (26.63 and 25.86mU/lmolHb) compared with the control (37.84mU/lmolHb). In addition BUChE activity in plasma was lower in the T3 (7.01micromol BTC hydrolyzed/h/mL) than the T5 and C groups (9.84 and 12.00micromol BTC hydrolyzed/h/mL). This study therefore, shows that reductions in the activity of cholinesterase occur in acute infection by T. evansi in rats and this demonstrates an important change occurring in animals infected by the protozoan and may indicate a potential role the enzymes play in the mechanism of disease.
    Experimental Parasitology 02/2010; 125(3):251-5. · 2.15 Impact Factor
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    ABSTRACT: The aim of this study was to report the gastrointestinal parasitism in white-lipped peccary (Tayassu pecari) in Brazil. Fecal samples of three animals kept in captivity in the state of Rio Grande do Sul were collected. Samples were analyzed by the centrifugal flotation technique with zinc sulfate and by the Kinyon staining method. All animals showed mixed infection by cysts of Giardia sp. and Balantidium sp. and by oocysts of Cryptosporidium sp. and Eimeria sp. This is the first report of these four genera of protozoa in T. pecari. Este estudo teve como objetivo registrar o parasitismo gastrintestinal em queixada (Tayassu pecari) no Brasil. Foram colhidas amostras de fezes, de três exemplares mantidos em cativeiro no estado do Rio Grande do Sul. As amostras foram analisadas pelas técnicas de centrífugo flutuação com sulfato de zinco e coloração de kinyon para pesquisa de parasitos. Em todos os animais observou-se uma infecção mista por cistos de Giardia sp. e Balantidium sp., além de oocistos de Cryptosporidium sp e Eimeria sp. Este estudo relata o primeiro registro destes quatro gêneros de protozoários em T. pecari.
    Semina : Ciências Agrárias. 01/2010;
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    ABSTRACT: The purpose of this study is to report the occurrence of new serovars of Leptospira interrogans in cavy in Brazil. Blood without anticoagulant was collected from five Cavia aperea to obtain serum for further testing with serum agglutination using eight serovars of L. interrogans. It was observed that four animals had titers for L. butembo, L. bratislava, and L. hardjo. We believe that cavy can be reservoirs and disseminators of these serovars of L. interrogans.
    Comparative Clinical Pathology 01/2010; 19(1):119-120.
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    ABSTRACT: The aim of this research study was to evaluate the gastrointestinal parasitism in ferrets (Mustela putorius furo) kept in captivity in the southern region of Brazil. Fecal samples of two three-year-old ferrets, a male and a female, were analyzed by the direct smear method, the centrifugal flotation technique with zinc sulfate, and tha Kinyoun staining method. Oocysts of Cryptosporidum sp. were observed in the faeces of both animals. This is the first report of this protozoan in ferrets in Brazil.
    Biotemas. 01/2010;
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    ABSTRACT: This study reports the gastrointestinal parasitism by Giardia sp. and Cryptosporidium sp. in blue macaw (Anodorhynchus hyacinthinus) in the southern region of Brazil. Fecal samples of two species kept in captivity in the state of Rio Grande do Sul were analyzed by the direct smear method, centrifugal flotation technique with zinc sulfate and Kinyoun staining technique for research of parasites. Mixed infection by eggs of Capillaria, cysts of Giardia sp. and oocysts of Cryptosporidium sp. was observed. This is the first report this protozoa in blue macaw.
    Biotemas. 01/2010;

Publication Stats

128 Citations
207 Downloads
37.43 Total Impact Points

Institutions

  • 2008–2013
    • Universidade Federal de Santa Maria
      • Department of Microbiology and Parasitology
      Santa Maria da Boca do Monte, Rio Grande do Sul, Brazil
  • 2012
    • Universidade do Estado de Santa Catarina
      Joinville, Santa Catarina, Brazil
  • 2010
    • Universidade Federal do Rio Grande do Sul
      Pôrto de São Francisco dos Casaes, Rio Grande do Sul, Brazil