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 (124)58.13 Total impact

  • [Show abstract] [Hide abstract] ABSTRACT: The acaricidal effect of seven essential oils was examined in vitro against the cattle tick (Rhipicephalus microplus). Engorged female ticks were manually collected in farms of Southern Brazil and placed into petri dishes (n=10) in order to test the following oils: juniper (Juniperuscommunis), palmarosa (Cymbopogon martinii), cedar (Cedrus atlantica), lemon grass (Cymbopogon citratus), ginger (Zingiber officinale), geranium (Pelargonium graveolens) and bergamot (Citrus aurantium var bergamia) at concentrations of 1, 5, and 10% each. A control group was used to validate the tests containing Triton X-100 only. Treatment effectiveness was measured considering inhibition of tick oviposition (partial or total), egǵs weight, and hatchability. C. martinii, C. citratus and C. atlantica essential oils showed efficacy higher than 99% at all concentrations tested. In addition, J.communis, Z. officinale, P. graveolens, and C. aurantium var bergamia oils showed efficiency ranging from 73 to 95%, depending on the concentration tested, where higher concentrations showed greater efficacy. It was concluded that essential oils can affect tick reproduction in vitro by inhibiting oviposition and hatchability.
    No preview · Article · May 2016 · Journal of Advanced Research
  • [Show abstract] [Hide abstract] ABSTRACT: This study aimed to induce lactation in Lacaune sheep and to verify its influence on milk production and composition, oxidative/antioxidant profile, and biochemical variables in serum and milk. A group of ewes (group A, n = 7) was induced with estradiol (0.5 mg/kg body weight (BW)) and progesterone (1.25 mg/kg BW) on days 1 to 7, bovine somatotropin (BST; 250 mg/animal) on days 11 and 40, as well as dexamethasone (16 mg/day) on days 19, 20, and 21. For comparison, another group of pregnant ewes was used as control (group B, n = 5). Blood and milk samples were collected for biochemical analysis, oxidative/antioxidant profile analysis, and determination of individual volume and chemical composition. The hormonal protocol was effective to induce lactation; however, milk production was 79 % lower than the control group. Milk fat, protein, and total solids were significantly lower (p < 0.05) in group A when compared to group B. Hormonal induction caused changes in blood components such as increased amounts of albumin, ALT, and gamma-glutamyl transferase (GGT) and decreased urea compared to the control group. Seric antioxidant levels (ferric reducing ability of plasma (FRAP), group A) were significantly increased, and reactive species of oxygen decreased dramatically compared to group B. Milk FRAP levels were lower in group A, and advanced oxidation protein product (AOPP) levels were higher compared to group B. Therefore, it was concluded that the protocol for lactation induction of Lacaune ewes was not effective in the biochemical change in blood and milk.
    No preview · Article · May 2016 · Comparative Clinical Pathology
  • [Show abstract] [Hide abstract] ABSTRACT: The objective was to assess the effects of using drying powder and iodine solution during navel cords disinfection handling on performance and blood variables (total protein, albumin, and globulin) in newborn piglets. Four treatments were used: (1) tie, cut, and iodine (TCI); (2) tie, cut, and spread drying powder (TCDP); (3) tie, cut, iodine, and drying powder (TCIDP); and (4) no navel cord handling (NNCH). There were five sow used and from each one, eight piglets were chosen within each parturition, with two piglets by treatment (one male and one female), totaling 10 repetitions per treatment. During the first, second, and third week from parturition the body weight gain, blood parameters (seric total proteins, albumin, and globulins), and navel healing score were assessed. Body weight gain and navel healing score were not different among treatments. Serum albumin had greater levels in TCDP compared with TCIDP and NNCH. Those results indicated no influence of different methods of disinfection of the navel on body weight gain, navel healing, and handling, but influences in serum albumin levels.
    No preview · Article · Mar 2016 · Comparative Clinical Pathology
  • [Show abstract] [Hide abstract] ABSTRACT: In South America, capybaras (Hydrochoerus hydrochaeris) as well as coatis (Nasua nasua) are the reservoir hosts of Trypanosoma evansi. Capybaras from a T. evansi nonendemic area in the State of São Paulo, southeastern Brazil, were culled because of an ongoing outbreak of Brazilian spotted fever; serum samples from these capybaras were tested for antibodies to T. evansi. Of the 172 sera tested, 17 (9.9%) were seropositive by card agglutination test, with antibody titers of 1:8–1:128; 14 (8.1%) of these 17 seropositive sera were also seropositive by indirect fluorescent antibody test, with antibody titers of 1:16–1:256. Both serologic techniques proved to be efficient, with similar results for detection of antibodies to T. evansi in capybaras from a nonendemic area in Brazil.
    No preview · Article · Mar 2016 · Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc
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    [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
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    [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
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    [Show abstract] [Hide abstract] ABSTRACT: Background: Infection by helminthes is a main problem affecting sheep, causing significant economic losses. Among these parasites that may affect sheep, Haemonchus contortus, a hematophagous parasite caused of anemia. The anemia due to parasitosis causes animal apathy, the main goal of most studies is to show how anemia affects animal performance, with little research on the relationship of animal behavior and helminthosis. Therefore, the objective of this study was to evaluate the effect of anemia caused by helminthes on the behavior of pregnant ewes before and after antihelminthic treatment. Material, Methods & Results: Pregnant ewes (n = 18) Lacaune breed from the same herd in Southern of Brazil were classified into three groups of six animals each according to their degree of anemia based on the Famacha method (F) and hematocrit counts (H) in addition to fecal examination on day 0 of the study. The groups were formed as follow: Group A (level 1-2 (F), (H) >= 30%), Group B (level 3 (F); (H) among 21-29%), and Group C (level 4-5 (F); (H) <= 20%). Famacha method, hematological analysis and fecal examination were repeated at the end of the experiment on day 18. Behavioral assessment was done concomitantly by two methods: direct temporal observation with real-time registration and continuous observation with conspicuous registration for each event performed by the animal. Animal behavior was observed during six periods (P1 to P6) six h a day (08: 00-10: 00 AM, 12: 00-02: 00 PM, and from 04: 00-06: 00 PM), being tree-point periods prior (P1, P2 and P3) and three after the antihelminthic treatment (P4, P5 and P6). The animals from the Group C had higher eggs per gram (EPG) counts in faces when compared to other groups. The animals from the Group B showed higher ratios of the variable lying ruminating (1.74) when compared to the Group A. Animals from the Group C showed higher ratio for the variable ruminating standing (1.38), lying idle (4.75) and standing idle (1.34), compared to females from the Group A. In conspicuous method, it was noticed that animals from the Group B showed lower ratio of the variable drinking water (0.87) when compared to the Group A. The Group C showed higher ratios of the variable eating (1.47), when compared to the Group A. Discussion: Behavioral changes mostly of the time may be the first indication of disease, since there is a direct link between behavior and animal health. A study in order to identify the effects of H. contortus experimental infection on lambs and observed that there is an effect on age, behavior, and growth rate, but the degree of parasite infection did not influence the pattern of animal behavior, different from our experimental study. In our study the anemic animals from the Group C where seen eating and drinking more frequently but they were also standing and lying idle for longer periods of time. These behaviors may be related to the need of blood replacement due to anemia faced after helminthic infection. In addition, studies describe that gastrointestinal parasitism altered animal grazing behavior with parasitized animals becoming more selective when avoiding contaminated pasture, taking smaller bites at reduced bite rates compared with non-infected animals. Based on our results, we were able to conclude that the degrees of anemia, and therefore the helminthosis, play important influence on the behavior of pregnant ewes.
    Full-text · Article · Jun 2015 · Acta Scientiae Veterinari
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    [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
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    [Show abstract] [Hide abstract] ABSTRACT: Background: Gastrointestinal nematode infections are a major problem for sheep production, leading to large economic losses as a result of the high costs for prevention and treatment. In helminthiasis, the most common clinical signs are weight loss, submandibular edema, diarrhea, and anemia. Among the many nematodes, stands out in the Brazilian states Haemonchus contortus and Trichostrongylus colubriformis, as well as these parasites have developed a number of anthelmintic resistance. Therefore, the aim of this study was to evaluate the cost-benefit of different antihelminthic protocols in naturally infected sheep. Material, Methods & Results: The study was conducted for one year in a sheep farm located in Southern Brazil. Three groups (A, B and C) with 10 adult sheep each were used. The group A was treated without drug rotation, and levamisole hydrochloride was used at intervals of 60 days. The group B was treated with levamisole hydrochloride at months 2, 4, 8 and 12 and albendazole at month 6 (antiparasitic treatment with pharmacological rotation). Animals from the group C were treated after selection by the Famacha method, which is based on the degree of anemia of their mucous ocular membranes. The results showed that the animals of the group C had lower values of eggs per gram of feces (EPG), and thus, they were treated more efficiently. The main genera of the Trichostrongylidae family observed in this study were Haemonchus, Trichostrongylus, and Teladorsagia, but were no difference between groups related to the percentage of helminths the Trichostrongylidae family. Furthermore, it was found that the cost of anthelmintic protocols used for groups B and C was 7.4 and 49.6% less than the cost of the methods used in the group A, respectively. We have noted that if all the animals were treated based on the Famacha method with levels 4 and 5, only 20 (group A) and 22 (group B) animals would have received treatment, which characterizes an unnecessary cost of 66.6 and 63.3% for group A and B, respectively. The group C showed the lowest number of eggs per gram of feces, indicating greater treatment efficiency when compared to group A. Discussion: Some methods are used to control nematodes including Famacha, which is related to hematophagous helminths and its most significant advantage is the reduction of the number of treatments needed, reducing the chances of helmintic resistance, as observed in the current study. In this research it was found that the EPG counts were reduced after treatment, but it was not zero in most animals, which indicates a degree of resistance. The resistance can be defined as the decrease in the efficacy of a drug against the parasite population that is generally susceptible, an evident fact in this study for H. contortus and Trichostrongylus sp. According to researchers, resistant parasites are probably in a lower number, but the selection pressure exerted by a given drug may favor the increase of resistant on individuals in the same population of parasites that were originally susceptible to the treatment. Therefore, the existence of an anthelmintic treatment program is important in a herd, in order to delay the occurrence of resistance and for better production performance. The Famacha method minimizes the use of antihelmithics and in addition, it mitigates the possibility of drug residues on meat, milk and the environment. Therefore, it is possible to conclude that the Famacha method showed the best cost-benefit response, with lower treatment costs to producers, and consequently, it minimized the chances of drug residues in animal products and in the environment.
    Full-text · Article · Nov 2014 · Acta Scientiae Veterinari
  • [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
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    [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
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    [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.
    Full-text · Article · Aug 2014 · Comparative Clinical Pathology
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    [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
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    [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
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    [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.
    Preview · Article · Mar 2014 · Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria
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    [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
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    [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