Aleksandro Schafer da Silva

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

Are you Aleksandro Schafer da Silva?

Claim your profile

Publications (112)54.33 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Toxoplasma gondii is a mammalian parasite with a wide geographical distribution. Some seropositive animals for T. gondii can be asymptomatic, including humans. This study aimed to investigate the presence of antibodies against T. gondii in the serum of 50 vampire bats (Desmodus rotundus) from the western region of Santa Catarina State, Brazil, using the modified agglutination test (MAT), in a dilution of 1:25. The results showed 10 % (5/50) are seropositive for T. gondii, showing that bats from that region had contact with T. gondii and are probably infected.
    Full-text · Article · Jan 2016 · Comparative Clinical Pathology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Ehrlichia canis and Babesia vogeli comprise a group of globally distributed pathogens transmitted by ticks. Leishmania infantum is transmitted by Lutzomyia longipalpis, etiological agent of leishmaniasis. The pathogens affect the animals; and can also affect the human. An imbalance between oxidants and antioxidants compounds causes an increase in free radicals, and other reactive oxygen species (ROS) has play an important role in tissue damage in a variety of pathological processes, as parasitic disease. The objective of this study was to evaluate the nitric oxide levels, protein oxidation and total antioxidant status in serum of dogs infected by L. infantum, E. canis and B. vogeli. Materials, Methods & Results: Blood samples from dogs originating from the city of Campo Grande, Mato Grosso do Sul state, Brazil were collected to research hemoparasites by polymerase chain reaction (PCR) using specific primers for each parasite. Serum samples obtained from 54 dogs with single and co-infection were used this study: L. infantum (n = 19), E. canis (n = 8), B. vogeli (n = 5), L. infantum and E. canis (n = 12), L. infantum and B. vogeli (n = 4), and E. canis and B. vogeli (n = 6), as well as 17 normal controls (uninfected). Samples were stored at -80 degrees C for further evaluation of NOx, AOPP, and FRAP levels using Cobas Mira automated analyzer, and results were expressed as mu mol/L. NOx, AOPP and FRAP levels were increased (P < 0.01) in dogs infected by parasites when compared to uninfected animals. Levels of NO. and AOPP in dogs naturally infected by Babesia vogeli and Ehrlichia canis, respectively, did not differ from the control group (uninfected). The higher NOx levels were observed in the serum of dogs with co-infection by L. infantum and E. canis, and L. infantum and B. vogeli (P < 0.01). Altogether, our results indicate that dogs naturally infected by L. infantum, E. canis and B. vogeli developed a state of redox imbalance. Discussion: Oxidative stress in dogs infected by L. infantum, Ehrlichia canis, and B. vogeli, single or co-infected were verified this study. As a result, naturally infected dogs sampled in the present study showed augmented levels of ROS, as well as in serum samples of dogs infected by Babesia gibsoni, Leishmania spp., Hepatozoon canis, and Trypanosoma evansi. Nitric oxide increased (detected by high NOx levels) can be a marker of oxidative stress, as well as an important mediator of inflammatory response. In experimental conditions, an increased level of NOx in dogs infected with E. canis was observed, and researchers say this increase was directly related to the pathogenesis of the disease. The imbalance of oxidants and antioxidants is present in various animal species in many pathological situations including parasitic diseases, as in dogs infected by hemoparasites showed increased oxidative markers (NO. and AOPP) associated with increased antioxidant levels (FRAP), which features a status of oxidative stress. The increase of FRAP is interpreted as the elevation of total antioxidant levels, i.e. enzymatic and non-enzymatic. The increased antioxidant is good to the host, it has the function of neutralizing the oxidizing or reducing that when high levels are toxic to cells and tissues. Therefore, we suggest that the infections caused by these hemoparasites cause oxidative stress and this process may participate in disease pathology.
    No preview · Article · Nov 2015 · Acta Scientiae Veterinari
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study aimed to assess the parameters of milk quality of properties with different technological standards. Twenty five properties were analyzed from 7 countries from the West of Santa Catarina, and classified according to production technologies (feeding, breeding and management practices in general), capital used in the activity, technological standard of machinery, equipment and infrastructure. Ten properties were classified as low technological standard, 8 intermediate standard and 7 high technological standard. The milk's quality data of each property (fat, protein, somatic cell count (SCC) and total bacterial count (TBC)) were supplied by dairy products, being used the average of the months of February, March and April of 2013. The data was subjected to multivariate statistical analysis and variance. It was found that the properties of low technological standard had higher fat content in milk, followed by intermediate and high standard which didn’t differ. The protein contents were higher in the properties of low standard with relation to intermediate standard, being that the high-tech standard didn't differ from the other groups. With regard to TBC, the properties of low-tech showed higher values when compared to the other groups, while the SCC did not differ between the different technological standards. We concluded that the technological standard of the properties influenced the parameters of protein, fat and TBC, being that in according with increased of the level of technological of properties, there was a decrease in these parameters, except that SCC didn’t show the same behavior, not being influenced by technological standards. The percentage variations in milk protein and fat were explained by racial pattern of the animals and the amount of concentrate supplied to the animals. The TBC was influenced by the milking hygiene practices, such as milking system’s pre-disinfection and the use of hot water in the sanitation of the equipment. © 2015 Universidade Federal de Uberlandia. All rights reserved.
    Full-text · Article · Nov 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective: To verify the trypanocidal effectiveness of aescin and aescin liposomes against Trypanosoma evansi in vitro and in vivo. Methods: Aescin and aescin liposomes were used in vitro on trypomastigotes at different concentrations (0.5%, 1.0% and 2.0%) and exposure times (0, 1, 3, 6 and 9 h). In vivo tests were performed using mice as the experimental model. Trypanosome evansi infected mice were treated with aescin and aescin liposomes with doses of 60 and 100 mg/kg during 4 d. Results: The three concentrations tested in free form and nanoencapsulated showed trypanocidal activity in vitro, completely eliminating the parasites in small concentration after 6 h of assay. Animals treated with aescin (100 mg/kg) and aescin liposomes (100 mg/kg) showed increase in longevity, however without curative effect. Conclusions: Active compounds present in natural products, such as aescin, may potentiate the treatment of trypanosomosis when used in association with other trypanocidal drugs.
    Full-text · Article · Dec 2014 · Asian Pacific Journal of Tropical Biomedicine
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: In Brazil, the tick Rhipicephalus microplus is a serious problem for beef and milk cattle due to the damage caused directly to the animal. Ticks are responsible for major economic losses related to production, especially in breeds of European origin, prevalent in Southern Brazil. The use of most acaricides may allow the survival of some tick that transmits this characteristic to future generations, consequently each successive treatment is a process of selection. The lack of technical guidance on how to control ticks may contribute to the emergence of new resistant strains of ticks. The objective of this study was to test the efficacy of antiparasitic drugs on tick populations (Rhipicephalus microplus) from the Western region of Santa Catarina, Brazil. Materials, Methods & Results: Thirty-one farms participated in this study and 70 engorged female ticks were collect from each property. They were divided into seven groups of 10 specimens each. Ticks were exposed to six commercial drugs: amitraz (A); cypermethrin, chlorpyrifos, and citronellal (B); diazinon (C); diclovos and chlorpyrifos (D); cypermethrin (E); cypermethrin, chlorpyrifos, and piperonyl butoxide (F); and one group was used as a control to validate the test (G: no drug). Tests with acaricides followed standard protocols, recommended for in vitro testing. The effectiveness of the product was calculated based on egg laying and hatching. The drug tested is considered effective if the result was more than 95%. The number of farms with populations of resistant ticks were 13 (41.9% - group A), 2 (6.45% - group B), 15 (48.38% - group C), 6 (19.35% - group D) and 12 (38.7% - group E). Ticks from the group F did not show resistance to the tested products. i.e., all farms obtained 100% efficiency. Among the products tested that showed the highest efficacy were the combinations of three or two active principle as cypermethrin, chlorpyrifos and piperonyl butoxide (group F 100%), cypermethrin, chlorpyrifos and citronella (group B - 99.04%), and dichlorvos and chlorpyrifos (group D - 92.53%). However, products with only one active principle showed lower efficiency such as amitraz (group A - 87.94%), diazinon (group C - 70.71%), and cypermethrin (group E - 73.15%). Discussion: These results are very similar to other studies conducted recently in different Brazilian regions, but unknown in Western Santa Catarina, which currently has the largest dairy herd in the Santa Catarina State. In this study it was found that farmers are unaware of important tests to control tick, like the immersion test of engorged females that contributes to parasite control, identifies ineffective drugs and reduces labor costs. As researchers reported the inappropriate use of antiparasitic drugs like subdosage or superdosage, and the high frequency of acaricide use, may select and propagate the occurrence of resistance selection pressure. Therefore, it is concluded that the resistance of ticks is a problem present in the majority of the Western Santa Catarina properties. The current study shows that 81.7% of the tested tick population of parasitic resistance presented to one or more drugs. This study found that the cattle farmers were not aware of tests that detect ticks susceptibility to acaricides and did not adopt proper technical procedure when using chemicals. These indicate the need to educate cattle farmers on considering resistance as criteria, considering efficiency and cost of the treatment.
    No preview · Article · Sep 2014 · Acta Scientiae Veterinari
  • Source
    [Show abstract] [Hide abstract]
    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.
    Preview · Article · Sep 2014 · Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria
  • [Show abstract] [Hide abstract]
    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.
    No preview · Article · Aug 2014 · Comparative Clinical Pathology
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Jun 2014 · The Korean Journal of Parasitology
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Mar 2014 · Comparative Clinical Pathology
  • [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.
    No preview · Article · Mar 2014 · Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Jan 2014 · Parasitology
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Jan 2014 · Small Ruminant Research
  • Andréia Volpato · Marcelo Agostini · Alexandre Alberto Tonin · Aleksandro Schafer da Silva
    [Show abstract] [Hide abstract]
    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.
    No preview · Article · Nov 2013 · Comparative Clinical Pathology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: The cholinergic system is involved in many biological functions in mammals and is associated with pathogenesis of infectious diseases, as has participation in transmission of nerve impulses in cholinergic synapses, haematopoiesis, regulation of inflammatory markers, production and coordination of movement, and memory. Rangelia vitalii is a parasite endemic to south of Brazil. This parasite multiplies in the blood and can be visualized in plasma in its free form and/or within leukocytes and erythrocytes, causing various pathologies. Therefore, the purpose of this study was to investigate the activity of cholinergic system enzymes in dogs experimentally infected with R. vitalii. Materials, Methods & Results: Twelve dogs were used, divided into two groups: control group (n = 5), consisting of healthy animals, and infected group with R. vitalii (n = 7). Fresh blood samples of these infected animals were inoculated in seven dogs (2 mL/dog through the jugular vein). Blood samples were collected on days 0, 10 and 20 post-infection (PI). Butyrylcholinesterase (BChE) activity was measured in serum and acetylcholinesterase (AChE) in lymphocytes and whole blood. Boold samples were diluted 1: 50 (v/v) in lysis solution (0.1 mmol/L potassium/sodium phosphate buffer containing 0.03% Triton X-100) and frozen (-20 degrees C by 7 days) to determine AChE activity in whole blood. Lymphocytes were also obtained from whole blood with EDTA by gradient separation using Ficoll-Histopaque T plus to AChE activity this cell. After analysis of the samples, was observed that the dogs infected with R. vitalii presented a significant (P < 0.01) increase in AChE activity in whole blood on days 10 and 20 PI. However, the infected group showed a reduced activity in AChE in lymphocytes (P < 0.01) and BChE in serum (P < 0.05) on day 20 PI. Discussion: According to the literature, infected dogs R. vitalii develop regenerative anemia evidenced by an increase in the erytroid precursors in bone marrow associated with alterations of leucogram as leukopenia, neutropenia, eosinopenia, lymphocytosis and monocytosis. Furthermore, it was observed severe thrombocytopenia, with alteration in platelet aggregation and activity of enzymes involved in the control of ATP, ADP and adenosine levels on platelets, thereby influencing hemostasis and contributing to the typical bleeding disease. AChE activity in whole blood was increased in dogs parasitized by R. vitalii observed in this study. This increase may be a compensatory effect to severe anemia caused by the parasite infection, because this enzyme is involved in the maturation of erythrocytes and in the regulation of hematopoiesis. In the present study, we found that the reduction in AChE activity in lymphocytes is associated to lymphocytosis; and it is known that ACh is produced within lymphocytes and has the ability to negatively modulate the immune response, acting directly on the inhibition of inflammatory mediators. Therefore, the decrease of AChE activity may have an anti-inflammatory action in order to have more free ACh to bind lymphocytes and inhibit inflammation. The enzyme BChE can also act as an inflammatory marker in various diseases, similar to AChE, because the enzyme can hydrolyze acetylcholine when AChE is inhibited. In conclusion, our results indicate that canine rangeliosis alters the activity of cholinesterase's, which may be involved in the pathogenesis of the disease, as well as various pathological conditions.
    No preview · Article · Oct 2013 · Acta Scientiae Veterinari
  • [Show abstract] [Hide abstract]
    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.
    No preview · Article · Sep 2013 · Journal of Parasitology
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Sep 2013 · Journal of Medical Entomology
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Aug 2013 · The Korean Journal of Parasitology
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Jul 2013 · Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria
  • Aleksandro Schafer Da Silva · Alexandre Alberto Tonin · Leandro Sâmia Lopes
    [Show abstract] [Hide abstract]
    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.
    No preview · Article · Jul 2013 · Journal of Equine Veterinary Science
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Trypanosoma evansi is a flagellate which belongs to the salivate section, commonly observed parasitizing blood of equines, ruminants, pigs, dogs and wild animals in different regions of the world. It causes many losses to farmers due to death of animals and drug spending in endemic areas. The treatment of this disease in Brazil is only performed with diminazene aceturate; however it has been ineffective for many animals. During the lats years many studies have been carried out with natural products such as the essential oils. Copaiba oil stands out due some properties described as anti-inflammatory, healing, antiedematogenic, antitumor, parasitic and antibacterial. Therefore, this study aimed to test, in vitro and in vivo, the susceptibility of T. evansi to copaiba oil. Materials, Methods & Results: The oils used in this study were obtained from Copaifera reticulata and Copaifera duckei trees, commonly found in the Tapajos National Forest. The procedure received authorization of IBAMA due the scientific purposes. This study identified three oils identified as copaiba 4-C (C. reticulata), copaiba 5-C (C. duckei) and copaiba 8-C (C. reticulata). The bioassay was performed in vitro using specific culture medium for T. evansi, previously described by Baltz, 1985. Copaiba oil was dissolved in dimethyl sulfoxide (DMSO) and tested in three concentrations (0.5, 1.0 and 2.0%) in culture medium containing the parasite. To the control test (without oil) the same volume of DMSO (10 mu L) was added. Dimnazene aceturate was also used as a positive control at 0.5% of concentration. The counting of trypanosomes was performed in triplicate in a Neubauer chamber after 1, 3, and 6 hours after the experiment onset. For the tests in vivo, mice were infected (n = 40) and divided in 5 groups of 8 animals each. Group A consisted of healthy animals and Group B comprised animals infected with T. evansi and untreated. The other groups were infected and treated orally with oil of copaiba 4-C (Group C), copaiba 5-C (Group D) and copaiba 8-C (Group E), using a dose of 0.63 mL/kg/day for five consecutive days at intervals of 24 hours. In vitro tests with copaiba oil showed a reduction in the number of alive trypanosomes for the three tested concentrations, when compared to the control test after 1 and 3 h, similar to what occurred with testing aceturate. At 6 hours, it was not observed alive parasites in the test groups, differently from the control group which had an increase of trypanosomes compared to the time zero. The trypanocidal activity had a dose-dependent effect. In the in vivo experiment, the oil of copaiba administered orally had no curative efficacy for any of the groups; however group D treated with C. duckei showed prolonged longevity of the mice when compared to the groups B and C. Discussion: Trypanosoma cruzi and Leishmania amazonensis have been challenged on their susceptibility to oil of copaiba, with obtention of trypanocidal and leishmanicidal effects, similar process thet occurred in this study with T. evansi. According to scientific literature the copaiba oil increases the membrane permeability, as well as provides the depolarization of the mitochondrial membrane in parasite cells. A group of mice in this study showed prolonged longevity, showing that the variation of their compositions influence the trypanocidal effect. Based on these results it was concluded that the T. evansi may is susceptible to the oil of copaiba. Therefore, it can be natural product used as a new alternative and supplementar activity in the treatment of this protozoan, as have been suggested for leishmaniasis.
    No preview · Article · Jun 2013 · Acta Scientiae Veterinari

Publication Stats

412 Citations
54.33 Total Impact Points

Institutions

  • 2012-2014
    • Universidade do Estado de Santa Catarina
      Joinville, Santa Catarina, Brazil
  • 2005-2013
    • 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