Veterinary Parasitology

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Browsing Veterinary Parasitology by Subject "Acaricide"

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    In Vitro Effecacy of Methanolic Extracts of Vernonia Amygdalina, Croton macrostachyus, Ricinus Communis and Petroleum Ether Extract of Millettia Ferruginea against Bovicola ovis and Rhipicephalus (Boophilus) Decoloratus
    (Addis Ababauniversity, 2015-06) Gizaw, Askale; Dr. Giro, Bulto
    In vitro loucicidal and accaricidal efficacy evaluation of Vernonia amygdalina, Croton macrostachyus, Ricinus communis and Millettia ferruginea against Bovicola ovis and Rhipicephalus decoloratus of cattle were carried out from January 2014 to April 2015. Crude methanol extracts of Vernonia amygdalina, Croton macrostachyus, Ricinus communis leaf and Petroleum ether extract of Millettia ferruginea seed oil were prepared for in vitro test at different time intervals. The four selected medicinal plants, at concentrations of 200, 100, 50, 25, 12.5 and 6.25mg/ml and a commercially used acaricide (0.1% diazinon), were examined using in vitro adult immersion test. In vitro loucicidal test showed all concentration of Millettia ferruginea oil (μl/ml), ≥25mg /ml concentration of Croton macrostachyus and 200 and 100mg/ml concentration of Ricinus communis had pronounced loucidal activity at 24hr of exposure. 200mg/ml concentration of Vernonia amygdalina and ≤6.25mg/ml concentration of Croton macr ostachyus had moderate loucicidal activity at 24hr of exposure. Moreover, the 200 and 100μl/ml concentration of Millettia ferruginea seed oil and 200mg/ml concentration of Ricinus communis leaf crude extract had high accaricidal activity (90-100%) against Rhipicephalus decoloratus while crude methanolic extracts of Croton macrostachyus and Vernonia amygdalina and even the positive control (diazinon) showed low acaricidal activity (<35%) against the tick species. All plants had significantly (P< 0.05) higher activity against lice than Rhipicephalus decoloratus ticks except Millettia ferruginea at (200 and 100μl/ml) and Ricinus communis (at 200 mg/ml) which showed both accaricidal and loucicidal activity. Therefore the present study concluded that Croton macrostachyus, Ricinus communis and Millettia ferruginea against Bovicola ovis whereas Ricinus communis and Millettia ferruginea against Rhipicephalus decoloratus could be used as potential alternative in the discovery of guide compounds that substitute commercially available acaricides. In addition, the low activity of diazinon on ticks compared to our plant extracts deserves further attention. Key Words: Acaricide, Bovicola ovis, in vitro, loucicide, medicinal plants, Rhipicephalus decoloratus
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    In vitro Louscidal and Acaricidal Activities of Alkaloid of Calpurnia Aurea and Fractions of Ricinus Communis Extracts Against Linognathus Ovillus and Amblyomma Variegatum
    (Addis Ababauniversity, 2016-06) Amante, Morka; Dr. Hailu, Yacob
    The present study was designed to evaluate the louscidal and acaricidal activities of alkaloids of Calpurnia aurea and fractions of Ricinus communis leaves extracts. Alkaloid of C. aurea and XIV solvent fractions of R. communis leaves extract at concentrations of 200, 100, 50, 25, 12.5 and 6.25 mg/ml were used for in vitro adult immersion test of ticks and lice, which then were monitored for their mortality rates for 24hrs. The activities of test substances were evaluated against Amblyomma variegatum and Linognathus ovillus, and compared with diazinon 60 EC. After 24hrs post exposure, two higher concentrations of 200 and 100 mg/ml of the alkaloid extract caused 100±0.5% and 100±0.6% lice mortality, and 100±0.33 and 93.3±0.33 tick mortality respectively. The alkaloid extract showed an insignificant difference in its acaricidal and louscidal activity when compared to the Diazinon 60EC at the same concentration (P > 0.05). LC50 and LC90 values (with 95% confidence limits) of the alkaloid of C. aurea for lice and tick were estimated 9.08 mg/ml (6.21-13.47), 17.65 mg/ml (11.71-22.49) and mg/ml 16.69 (11.77, 26.64), 31.69 mg/ml (21.25-50.72), respectively. Based on LC50 and LC90 values, alkaloid extract was found to be more effective in killing of lice than ticks. Dose response data of C. aurea alkaloid extract on L. ovillus and A. variegatum indicated the gradual increase in the mortality pattern with slopes of 3.1188, and 3.2321, and R2 values of 0.9702 and 0.9882 suggesting that 97.02, 98.82% data were correlated with log concentration, respectively. Chloroform and petroleum ether fractions of R. communis extracts showed less louscidal and acaricidal effects than the acetone and methanol fractions extracts based on the calculated LC50 and LC90. At higher concentration of 200 mg/ml, the chloroform and petroleum ether fractions extracts showed weaker activity on both A. variegatum and L. ovillus with significant difference (P < 0.05) when compared to that of diazinon after 24hr post exposure. As compared to the alkaloid extract of C. aurea, fractions of R. communis extracts were less lethal both to lice and tick. Alkaloid of C. aurea and fractions of R. communis extract were shown to induce tick and lice mortality in a time and dose-dependent manner. The results obtained in this study indicate that the alkaloid extract of C. aurea and the polar solvent fractions of R. communis have promising louscidal and acaricidal activities, lending support for further investigation of the plants to isolate the active components. Keywords: Acaricide, Alkaloid, Ambylomma, Calpurnia aurea, Louscidal, Ricinus communis