276 resultados para Nematode


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Seventy-seven males of Hypsiboas prasinus from 2 Atlantic forest fragments in the municipalities of Botucatu and Jundiaí, São Paulo State, Brazil, were examined for endoparasites. The frogs were captured in summer (January until March) and winter (July/August) of 2008 and 2009. Thirty-three males (75) from Botucatu were infected with Rhabdias cf. fuelleborni, cosmocerciid nematodes, and Cylindrotaenia americana. Twenty-five tree frogs (78.5) from Jundiaí were infected by Rhabdias cf. fuelleborni, Physaloptera sp., and cosmocerciid nematodes. Only cosmocerciid nematodes presented a statistically significance difference in prevalence (z 4.345; P < 0.001) and mean abundance (t 562.0; P < 0.001) between Botucatu and Jundiaí during the winter. Also, the cosmocerciids exhibited higher mean abundance (t 196.0; P 0.034) in winter when compared with summer at the Jundiaí site. Moreover, to our knowledge, this is the first report of C. americana in the Brazilian Hylidae. This study presents 4 new records of nematodes in H. prasinus. © 2012 American Society of Parasitologists.

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Monitoring the survival of nematophagous fungi is needed to establish periods of reapplication of formulations of nematophagous fungi to control the citrus nematode in the field. We monitored the survival of fungi: Arthrobotrys robusta, A. oligospora, A. musiformis Dactylella leptospora and Monacrosporium eudermatum in plots treated with 1, 2, 4, 6 liters of the formulation of fungi/plant or witness without the application, during the period of nine months with the first assessment six months after application and the other with intervals of three months after the first evaluation. The fungus D. leptospora was found only in the evaluation of 6 months after treatment application, indicated a short survival time in the soil. However, the isolated A. robusta, A. musiformis and A. oligospora were recovered in all evaluations and especially in plots treated with higher doses of the formulation and witness. Monacrosporium eudermatum was recovered in all experimental periods and even in assessing the witness portion of nine months after application. The fact of the presence of species of Arthrobotrys and M. eudermatum in control plots indicates that native species that were already orchard.

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Although tannin-rich forages are known to increase protein uptake and to reduce gastrointestinal nematode infections in grazing ruminants, most published research involves forages with condensed tannins (CT), while published literature lacks information on the anthelmintic capacity, nutritional benefits, and antioxidant capacity of alternative forages containing hydrolyzable tannins (HT). We evaluated the anthelmintic activity and the antioxidant capacity of plant extracts containing either mostly CT, mostly HT, or both CT and HT. Extracts were prepared with 70% acetone, lyophilized, redissolved to doses ranging from 1.0mg/mL to 25mg/mL, and tested against adult Caenorhabditis elegans as a test model. The extract concentrations that killed 50% (LC50) or 90% (LC90) of the nematodes in 24h were determined and compared to the veterinary anthelmintic levamisole (8mg/mL). Extracts were quantified for CT by the acid butanol assay, for HT (based on gallic acid and ellagic acid) by high-performance liquid chromatography (HPLC) and total phenolics, and for their antioxidant activity by the oxygen radical absorbance capacity (ORAC) assay. Extracts with mostly CT were Lespedeza cuneata, Salix X sepulcralis, and Robinia pseudoacacia. Extracts rich in HT were Acer rubrum, Rosa multiflora, and Quercus alba, while Rhus typhina had both HT and CT. The extracts with the lowest LC50 and LC90 concentrations, respectively, in the C. elegans assay were Q. alba (0.75 and 1.06mg/mL), R. typhina collected in 2007 (0.65 and 2.74mg/mL), A. rubrum (1.03 and 5.54mg/mL), and R. multiflora (2.14 and 8.70mg/mL). At the doses of 20 and 25mg/mL, HT-rich, or both CT- and HT-rich, extracts were significantly more lethal to adult C. elegans than extracts containing only CT. All extracts were high in antioxidant capacity, with ORAC values ranging from 1800μmoles to 4651μmoles of trolox equivalents/g, but ORAC did not correlate with anthelmintic activity. The total phenolics test had a positive and highly significant (r=0.826, p≤0.01) correlation with total hydrolyzable tannins. Plants used in this research are naturalized to the Appalachian edaphoclimatic conditions, but occur in temperate climate areas worldwide. They represent a rich, renewable, and unexplored source of tannins and antioxidants for grazing ruminants, whereas conventional CT-rich forages, such as L. cuneata, may be hard to establish and adapt to areas with temperate climate. Due to their high in vitro anthelmintic activity, antioxidant capacity, and their adaptability to non-arable lands, Q. alba, R. typhina, A. rubrum, and R. multiflora have a high potential to improve the health of grazing animals and must have their anthelmintic effects confirmed in vivo in both sheep and goats. © 2012.

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Gastrointestinal nematode (GIN) infection is a major cause of production losses in cattle. This study was carried out to evaluate the natural resistance against nematode infection in Crioulo Lageano and crossbred Angus male calves. Crioulo Lageano is a local cattle breed in the state of Santa Catarina, in southern Brazil. Ten weaned calves of each breed were grazed together on pasture and naturally infected with nematodes between July 2009 and December 2010. Once every 28 days, we collected fecal and blood samples for parasitological and immunological tests, as well as recording body weights. After 19 samplings, all animals were slaughtered for quantification and identification of GINs. We found that the animals had been infected with the following nematode species, in decreasing order by the mean number of specimens: Trichostrongylus axei, Cooperia punctata, Ostertagia ostertagi, Haemonchus placei, Oesophagostomum radiatum, and Trichuris spp. There were no significant differences between the Crioulo Lageano and crossbred Angus groups in terms of worm burden or nematode fecal egg count, nor in terms of the mean levels of immunoglobulin (G and A) against C. punctata and H. placei antigens, except in IgA mean level in abomasal mucus against H. placei adult worms that was significantly higher in crossbred Angus cattle (p<0.05). At the end of the study, the crossbred Angus cattle were heavier than were the Crioulo Lageano cattle (mean live weight, 507.35 and 390.3. kg, respectively). Comparative parasitological and immunological evaluation revealed no difference between two breeds in terms of their natural resistance against GINs. © 2012 Elsevier B.V.

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Ninety-five specimens from 13 species of lizard collected during a herpetofaunal monitoring programme of the Faxinal II power plant, municipality of Aripuanã, state of Mato Grosso, Brazil (southern Amazon region) were examined for helminths. A total of 21 helminth species (16 Nematoda, 1 Cestoda and 4 Trematoda) were recovered, with an overall prevalence of 67.37%. Seventeen new host records and seven new locality records are reported. A low number of specialists and core helminth species were found. Lizard body size was positively correlated with both the total number of helminth species and individuals. Active foragers exhibited higher helminth diversity. However, sit-and-wait foragers, especially Plica plica, had similar diversity values as active foragers and harboured more helminth species. The degree of similarity in helminth fauna was higher among closely related host species. Copyright © 2011 Cambridge University Press.

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The incidence of opportunistic fungal infections has increased in recent decades due to the growing proportion of immunocompromised patients in our society. Candida krusei has been described as a causative agent of disseminated fungal infections in susceptible patients. Although its prevalence remains low among yeast infections (2-5%), its intrinsic resistance to fluconazole makes this yeast important from epidemiologic aspects. Non mammalian organisms are feasible models to study fungal virulence and drug efficacy. In this work we have used the lepidopteran Galleria mellonella and the nematode Caenorhabditis elegans as models to assess antifungal efficacy during infection by C. krusei. This yeast killed G. mellonella at 25, 30 and 37°C and reduced haemocytic density. Infected larvae melanized in a dose-dependent manner. Fluconazole did not protect against C. krusei infection, in contrast to amphotericin B, voriconazole or caspofungin. However, the doses of these antifungals required to obtain larvae protection were always higher during C. krusei infection than during C. albicans infection. Similar results were found in the model host C. elegans. Our work demonstrates that non mammalian models are useful tools to investigate in vivo antifungal efficacy and virulence of C. krusei. © 2013 Scorzoni et al.

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The present study aimed to evaluate the persistent efficacy of a 3.5% doramectin* (700μg/kg) formulation compared to 3.15% ivermectin** (630μg/kg) treatment, administered subcutaneously at a dose of 1mL/50kg body weight in cattle experimentally infected with gastrointestinal nematodes. Seventy-two male crossbred Holstein cattle that were negative for helminth infection were divided into nine groups. Treatments of 3.5% doramectin (Groups 2, 4, 6 and 8) and 3.15% ivermectin (Groups 3, 5, 7 and 9) were administered on days 49, 42, 35 and 28 prior to challenge with infectious nematode larvae (L3). Animals in the control group (Group 1) received saline solution on day 49 before challenge. Beginning on day zero, each animal received 50mL orally of a mixed culture containing approximately 3,000 third stage larvae (L3) of Haemonchus (60%), Oesophagostomum (20%), Cooperia (15%) and Trichostrongylus (5%) for seven consecutive days, resulting in a total challenge of 21,000 larvae/animal. Due to the large number of cattle, autopsies were performed between days 28 and 35 after the last day of inoculation. The formulation containing doramectin (700 mcg/kg) achieved persistent efficacy against H. placei and C. punctata for 49 and 35days, respectively. The persistent efficacy of ivermectin (630 mcg/kg) against H. placei lasted for 49days, but this treatment was ineffective against C. punctata. Both formulations demonstrated persistent efficacy against T. axei for 49days. The persistent efficacy of doramectin (700 mcg/kg) and ivermectin (630 mcg/kg) lasted for 49 and 42days against O. radiatum, respectively. © 2012 Elsevier Ltd.

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The aim of this work was to evaluate the population density of Pratylenchus brachyurus and Pratylenchus zeae associated with Brachiaria brizantha, B. decumbens and B. humidicola and their influence on forage availability and quality. The experiment was conducte in the Hisaeda Farm, Terenos, MS, Brazil. Soil, roots and plant aerial part were harvest with ten replications each, in one square meter randomized sets encompassing three treatments: Good, Intermediary and Bad, visually characterized, considering the percentage of green material. P. brachyurus and P. zeae density were evaluated in soil and plant roots. Dry matter of green, dead and re-growth materials, plant nutritional status and forage quality were assessed in the aerial plant part. Soil fertility was determined in all harvested samples. Both nematode species were identified from all samples, with a larger numbe in the roots (between 87-311 P. brachyurus and 1-61 P. zeae.10 g-1) than in the soil (0-8 P. brachyurus and 1-39 P. zeae.200 cm-3), however, no significant differences were found in the number of specimens between treatments. Considering that these forage species are perennial and host Pratylenchus spp, there is a tendency to increase the population of these pathogens over time, becoming a serious phytosanitary problem.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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We studied the efficacy of infective juveniles (IJ) of Steinernema sp. strain JCL024 and Heterorhabditis sp. strain SL0708 on adults and nymphs of Collaria scenica under greenhouse conditions. Five doses were evaluated (2, 16, 78, 160 IJ) cm-2 leaf) for each nematode. The experiment was evaluated for 21 days every 24 hours, making mortality counts and assessment of damage on Kikuyo grass. The bugs showed 100% mortality after 15 days. Each bug produced an average of 13,000 IJ/6 days. As for the damage did not reach level 2 within 21 days prior to treatment without nematodes that damage introduced 3 with necrosis and apical leaf curl. Thus, Steinernema sp. strain JCL024 and Heterorhabditis sp. strain SL0708 exercised control bug on the grass and kept under the level of damage to the foliage.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Specimens (n= 41) of the amphisbaenid Amphisbaena wuchereri taken from a population in Minas Gerais state, south-eastern Brazil, were examined for gastrointestinal parasites. A single nematode species was found, Paradollfusnema amphisbaenia. This was a new host record for this nematode species. This parasite was encountered in the large intestine (prevalence of 100%), in the stomach (prevalence of 2%) and in the small intestine (prevalence of 7.3%). The intensity of infection ranged from 1 to 457 individual parasites per host and was positively correlated with body size of both male and female amphisbaenians. The discrepancy index (D) indicated that P. amphisbaenia tended to an even distribution in this host population. The nematode, which did not affect fat body mass, induced inflammatory infiltrations in the small intestine, indicating that the parasites might injure the host's organs. Copyright © Cambridge University Press 2012.

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The objective of this study was to evaluate different strategies for the application of entomopathogenic nematodes (EPN). Three different models of spray nozzles with air induction (AI 11003, TTI 11003 and AD-IA 11004), three spray pressures (207, 413 and 720 kPa), four different additives for tank mixtures (cane molasses, mineral oil, vegetable oil and glycerin) and the influence of tank mixture stirring time were all evaluated for their effect on EPN (Steinernema feltiae) viability and pathogenicity. The different nozzles, at pressures of up to 620 kPa, were found to be compatible with S. feltiae. Vegetable oil, mineral oil and molasses were found to be compatible adjuvants for S. feltiae, and stirring in a motorized backpack sprayer for 30 minutes did not impact the viability or pathogenicity of this nematode. Appropriate techniques for the application of nematodes with backpack sprayers are discussed. © 2013 Moreira et al.

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Due to the few studies about grafting in net melon, in order to obtain better control of soil pathogens, the aim of the present study was to evaluate 16 genotypes of Cucurbitaceae: Benincasa hispida, Luffa cylindrica, pumpkin 'Jacarezinho', pumpkin 'Menina Brasileira', squash 'Exposição', squash 'Coroa', pumpkin 'Canhão Seca', pumpkin 'Squash', pumpkin 'Enrrugado Verde', pumpkin 'Mini Paulista', pumpkin 'Goianinha', watermelon 'Charleston Gray', melon 'Rendondo Gaucho', melon 'Redondo Amarelo', cucumber 'Caipira HS' and cucumber 'Caipira Rubi', regarding to compatibility of grafting in net melon and resistance to Meloidogyne incognita, based on the reproduction factor (RF), according to Oostenbrink (1966). To assess resistance, the seedlings were transplanted to ceramic pots and inoculated with 300/mL eggs and/or second stage juveniles of M. incognita. At 50 days after transplanting, the plants were removed from the pots and the resistance was evaluated. The compatibility between resistant rootstock and grafts of net melon was determined by performing simple cleft grafting, in a commercial net melon hybrid of great market acceptance and susceptible to M. incognita (Bonus no. 2). The genotypes Luffa cylindrica, pumpkin 'Goianinha', pumpkin 'Mini-Paulista', melon 'Redondo Amarelo', watermelon 'Charleston Gray' are resistant to the nematode M. incognita. The better compatibilities occurred with the rootstocks melon 'Amarelo', which presented 100% of success, followed by pumpkin 'Mini-Paulista' with 94%. On the other hand, Sponge gourd, watermelon 'Charleston Gray' and pumpkin 'Goianinha' showed low graft take percentages of 66%, 62% and 50%, respectively.

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As a result of the need to develop new active principles for the control of endoparasites in ruminants, the present in vivo study evaluated a formulation containing 24% Aurixazol (48 mg/kg), a parasiticide molecule based on disophenolate of levamisole. Two experiments were conducted: one evaluating the anthelmintic efficacy of 24% Aurixazol (48 mg/kg) against gastrointestinal nematodes in naturally infected sheep, compared to an association of ivermectin (0.2 mg/kg) + albendazole (5.0 mg/kg) + levamisole (7.5 mg/kg) (IAL), and a second one which evaluated the persistent efficacy of the same formulation against immature stages (L4) and adults of Haemonchus contortus in experimentally infected animals. In experiment I, against H. contortus, the formulation of Aurixazol and the IAL association reached efficacies (arithmetic means) of 99.32% and 96.11%, respectively. For Trichostrongylus colubriformis, the efficacy values were 88.92% and 98.08% for Aurixazol and the IAL association, respectively. Both formulations were totally effective against Oesophagostomum columbianum (100%). The results of the statistical analysis demonstrated that the mean parasitic burden of treated animals was significantly different (P ≤ 0.05) compared to the average number of helminths diagnosed in animals from the control group for H. contortus, T. colubriformis and O. columbianum. Comparing only the treated groups, it was possible to verify that the average number of H. contortus recovered from animals treated with Aurixazol was different (P ≤ 0.05) when compared to the mean amount recovered from sheep treated with the IAL association. When evaluating the prevention of H. contortus infection in experiment II, Aurixazol did not present preventive efficacy. Up until 21 days after treatment the groups treated with Aurixazol contained less adults and L4 of H. contortus (P ≤ 0.05) when compared to the non-medicated control group. However, future studies will be necessary to assess the effectiveness of Aurixazol against nematode strains resistant to levamisole and disophenol, but the efficacy results described in this study allow to state that Aurixazol can, associated with other measures, become an important tool in the control of sheep nematodes. © 2013.