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Dermacentor nitens tick is commonly found in the equine auditory canal, where it causes economic losses due to its direct damage, causing blood spoliation, stress, transmission of pathogens, and predisposition to myasis and secondary bacterial infection in its hosts. In this study we evaluated the effect of ethanolic extracts of Cerrado plants on biological parameters of engorged females of D. nitens. Ethanolic extracts were prepared from the leaves of Schinopsis brasiliensis, Piptadenia viridiflora, Ximenia americana, and Serjania lethalis at 25-150 mg mL-1. Groups of 10 engorged adult females were treated with these extracts and compared with a control containing distilled water and another control with organophosphate, using five replicates for each group. Compared with the control with water, S. lethalis and X. americana extracts at 100 and 150 mg mL-1 significantly inhibited the posture ability. Differently, extracts of S. brasiliensis and P. viridiflora were the most effective in inhibiting larval hatching. Extracts of X. americana and P. viridiflora showed effective inhibition of reproductive parameters of the tick, presenting dose-dependent effect with IC90 78.86 and 78.94 mg mL-1, respectively. Theses effective extracts contained low condensed tannin levels and their HPLC chromatograms revealed the presence of flavonoids. The efficacies of P. viridiflora and X. americana extracts were higher than 90% indicating that these extracts are promising as alternative agents for D. nitens control.

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Anthelminthic resistant populations of Haemonchus contortus are a major problem in sheep rearing, but plant extracts may offer viable alternative treatments. In our preliminary studies, Piptadenia viridiflora was frequently selected by sheep grazing in the Cerrado. The present research evaluated its in vitro and in vivo anthelmintic activity. The HPLC chromatograms of P. viridiflora aqueous extract (AE) and ethanolic extract (EE) showed the presence of flavonoids. The total condensed tannin (proanthocyanidin) was 0.2 and 1.01% in AE and EE, respectively. In an egg hatching inhibition (EHI) test, the LC90 of AE was 2.4mg/mL, and, of EE, was 2.1mg/mL. After tannin extraction, higher EHI and lower LC90 were observed. In a larval development inhibition test, the LC90 of AE was 13.66mg/g of fecal culture. The highest dose of AE administered to mice (203.0mg/kg bw) was well tolerated, suggesting low toxicity. In vivo, AE was orally administered to lambs at 283mg/kg bw, and, at weeks one, two, and three post-treatment, the mean fecal egg count (FEC) was significantly lower than in untreated lambs (P<0.05). Blood parameters were normal and similar in untreated and treated sheep. For all lamb groups, the mean total serum protein was significantly higher at week two post-treatment than at other evaluated periods (P<0.05). Piptadenia viridiflora extracts had low condensed tannin content and exhibited high anthelminthic efficacy in vitro and significantly reduced FEC. Tannins were not shown to be the principal components affecting EHI, hence it is necessary to isolate and characterize the principal active P. viridiflora compounds, and to assess their possible synergism.

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Myracrodruon urundeuva Fr. All. é uma espécie pertencente à família Anacardiaceae, cuja planta pode ser utilizada como medicinal, na indústria de curtimento de couro, na arborização de ruas e praças, produzindo madeira de grande resistência mecânica. Diante disso, o objetivo deste trabalho foi determinar as melhores condições e períodos de armazenamento para conservação da viabilidade e vigor das sementes de M. urundeuva. As embalagens utilizadas para acondicionamento das sementes foram sacos de papel Kraft, algodão e de polietileno transparente, bem como folhas de papel alumínio. Em seguida as sementes foram armazenadas em ambiente natural de laboratório (25 ± 2ºC), freezer (-20 ± 2ºC), câmara fria (8 ± 2ºC) e geladeira (6 ± 2ºC). Em intervalos pré-determinados (0, 30, 60, 90, 120, 150, 180, 210 e 240 dias) avaliou-se o teor de água das sementes, porcentagem de emergência, índice de velocidade de emergência, comprimento e massa seca de plântulas. No ambiente de laboratório não houve conservação do vigor das sementes de M. urundeuva. A melhor condição para conservação de sementes de M. urundeuva foi obtida com o acondicionamento em sacos de papel Kraft, pano de algodão, plástico ou papel alumínio e manutenção em geladeira ou freezer, podendo também ser conservadas embaladas em papel ou alumínio, quando estocadas em câmara fria, por 240 dias. Alteração no vigor de sementes dessa espécie é primeiramente identificada pela redução da velocidade de emergência.

Myracrodruon urundeuva Fr. All. is a species belonging to the Anacardiaceae family, which can be utilized as a medicinal plant, or in the leather tanning industry, urban afforestation, and the production of wood with great mechanic resistance. The objective of this study was to determine the best conditions and storage periods for preserving the viability and vigor of M. urundeuva. Seeds conditioned in bags of Kraft paper, cotton, polyethylene or aluminum foil of mesh polyethylene were stored at room temperature (25 ± 2ºC), freezer (-20 ± 2ºC), cold (8 ± 2ºC) and refrigerator (6 ± 2ºC). At 30, 60, 90, 120, 150, 180, 210 and 240 days they were evaluated for seed moisture content, percentage of emergence, emergence speed index (ESI), seedling length and seedling dry matter. In the natural environment of the laboratory, there was no conservation of seed vigor M. urundeuva. The best M. urundeuva seed conservation condition was obtained with bags of Kraft paper, cotton, polyethylene or aluminum foil of mesh polyethylene in the refrigerator or freezer. M. urundeuva seeds can also be kept in paper bags or aluminum foil when stored in a refrigerated chamber, for 240 days. Seed vigor change in this species is initially identified by decrease in the speed emergence.

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Monthly collections were made of man-biting female blackflies: Simulium auripellitum Enderlein, S. guianense Wise, S. minusculum Lutz and S. nigrimanum Macquart (Diptera: Simuliidae) from four catching stations in the newly discovered focus of human onchocerciasis at Minaçu (13 degrees 35 minutes S 48 degrees 18 minutes W), 300 km north of Brasília in Goiás State. These provided baseline data on biting habits, population density and seasonal prevalence during the year before completion of the Serra da Mesa hydroelectric dam on the Rio Tocantins near Minaçu, in a project investigating the effect of dam construction on onchocerciasis transmission in the area. All four simuliid species were most abundant during the dry season, and only bit in low numbers (S. auripellitum S. minusculum, S. nigrimanum) or were absent (S. guianense) in the wet season. Simulium minusculum was the predominant species at all catching stations, being particularly abundant by the large River Tocantins. The other three species were mainly associated with smaller rivers. In the dry season, biting rhythms of S. minusculum varied with catching site, while S. nigrimanum showed peaks of activity in early morning and during the afternoon. Experimental infection with Onchocerca volvulus (Leuckart) (Nematoda: Onchocercidae), from a human volunteer, showed that this parasite could develop fully in the four simuliid species, which are all considered to be potential vectors in the area.

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