Browsing by Author "Tonui, Willy"
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Item Effect of Leaf Crude Extracts of Tarchonanthus Camphoratus (Asteraceae), Acalypha Fruticosa (Fabacea) and Tagetes Minuta (Asteraceae) on Fecundity of Phlebotomus Duboscqi(American International Journal of Contemporary Research, 2012-08) Mong’are, samuel; Ng’ang’a, Zipporah; Maranga, Rosebella; Osiemo, Zipporah; Ngure, Peter; Ngumbi, Philip; Tonui, WillyPurpose: This study was carried out to find out the effects of Tarchonanthus Camphoratus (Asteraceae), Acalypha fruticosa (Fabacea) and Tagetes minuta (Asteraceae) crude extracts on the fecundity of P. duboscqi. Materials and Methods: The extracts were prepared from the dried aerial parts of T. camphoratus, A. fruticosa, and T. minuta. Ten female sand flies were aspirated into vials where they were fed on a mixture of the plant extracts and sucrose solution prepared in a ratio of 1:1. Results: These crude plant extracts were found to reduce the fecundity of P. duboscqi significantly (P< 0.05). The extracts were found to reduce the fecundity of P. duboscqi by 73% (A. fruticosa), 53% (T. minuta) and 26% (T. camphoratus) (P< 0.05). Conclusion: The higher level of A. fruticosa, T. minuta and T. camphoratus activities would potentially reduce the population of sand flies. This study has provided proof of the effects of these medicinal plants on the vectorial capacity of sand flies.Item Immunostimulatory responses to crude extracts of Warburgia ugandensis (sprague) subsp ugandensis (canellaceae) by Balb/c mice infected with Leishmania major(Pan African Medical Journal., 2014-01-18) Ngure, Peter; Ng’ang’a, Zipporah; Kimutai, Albert; Kepha, Stella; Mong’are, Samuel; Ingonga, Johnnie; Tonui, WillyIntroduction: To determine the immunostimulatory potential of crude extracts of Warburgia ugandensis subsp. ugandensis with a soluble leishmanial antigen in vaccinating BALB/c mice. Methods: Seventy two female BALB/c mice were randomly assigned into six groups. The mice were vaccinated with soluble leishmania antigens (SLA) alone, hexane, ethyl acetate, and dichloromethane extract co-administered with SLA. Unvaccinated mice formed the control group. The induction of cell-mediated immunity following vaccination was determined by measuring in vitro lymphocyte proliferation and the production of interleukin (IL)-4 and gamma interferon (IFN-γ) determined by flow cytometry. Protection against L. major was determined by quantifying parasite burdens in L. major infected footpads using a limiting dilution assay and by measuring lesion sizes of the infected footpad compared to the contralateral uninfected footpad. Results: On vaccination with extracts of W. ugandensis subsp. ugandensis alone or as adjuvants when used in combination with Leishmania antigens, the hexane extract and the dichloromethane extract plus SLA stimulated moderate production of IFN-γ and low levels of IL-4.These mice were partially protected from cutaneous leishmaniasis as shown by the slow development of lesions and comparatively less parasite burdens. Conclusion: These data suggest that extracts of W. ugandensis subsp. ugandensis are suitable adjuvants for Leishmania vaccines. However, since W. ugandensis subsp. ugandensis has been shown to be effective against Leishmania parasites in vitro and in vivo, further studies ought to be conducted to determine its immunochemotherapeutic potential when co-administered with a soluble leishmanial antigen in vaccinating BALB/c mice.Item Potential Effects Of Pyrethrin Incorporated In Sucrose Baits Against Phlebotomus Duboscqi Neveu Lemaire (diptera: Psychodidae) In Leishmaniasis Control Strategies(Webmedcentral, 2010-11-06) Ireri, Laban; Mucheru, Obadiah; Ngure, Peter; Kepha, Stella; Kimuta, Albert; Cirindi, Josyline; Tonui, WillyBackground: Due to challenges of controlling leishmaniasis in Kenya through the vector, the efficacy of pyrethrin EC (Pymos™ 0.6% W/V) a mosquito adulticide was evaluated against Phlebotomus duboscqi while incorporated in sucrose as a possible complementary method. Methods: Pyrethrin was prepared into concentrations of 0.08, 0.25and 0.5 mg/ml using 10% sucrose. Ten male and female sand flies were each aspirated into jars and fed separately with the prepared solutions using cotton wool pads placed atop experimental jars and mortality monitored each day. The experiments were replicated three times. Results: Significant mortality (P< 0.05) for both sexes was observed. The concentration of 0.08mg/ml gave low adult mortality in 24 hours but amplified with time. In the 0.25 bioassay, mortality of females were 10 (33.3%) and males had 21 (70%) in 24 hours. The LD50 for females and males tied at 0.1 mg/ml in 48 hours of exposure. The concentration of 0.25 mg/ml was ideal at 48 hours of feeding where majority of the sand flies succumbed to the insecticide. There were significant mortality differences (P <0.05) between the concentrations but no significant difference (P>0.05) was observed in male and female mortality at 48 hours of exposure however. Although we cannot rule out sand fly mortality due to contact with the test material, the results of this study however suggest that control strategies using low-dose pyrethrin-sugar combinations as baits may be effective against phlebotomine sand flies and other sugar feeding pests of medical importance.Item The potential of the extracts of Tagetes minuta Linnaeus (Asteraceae), Acalypha fruticosa Forssk (Euphorbiaceae) and Tarchonanthus camphoratus L. (Compositae) against Phlebotomus duboscqi Neveu Lemaire (Diptera: Psychodidae), the vector for Leishmania major Yakimoff and Schokhor(Journal of Vector Borne Diseases, 0201-09) Ireri, Laban N.; Kongoro, Jedida; Ngure, Peter; Mutai, Charles; Langat, Bernard; Tonui, Willy; Kimutai, Albert; Mucheru, ObadiahBackground & objectives: Harmful effects of synthetic chemical insecticides including vector resistance, environmental pollution and health hazards have necessitated the current significance in the search for plant-based insecticide products that are environmentally safe and effective to leishmaniases control. The insecticidal activity of Tagetes minuta Linnaeus (Asteraceae), Acalypha fruticosa Forssk (Euphorbiaceae) and Tarchonanthus camphoratus L. (Compositae) extracts were investigated against Phlebotomus duboscqi Neveu Lemaire (Diptera: Psychodidae). Methods: The extracts were prepared from dried aerial parts soaked in methanol and ethyl acetate twice until the filtrates became clear, filtered and dried out by rotary evaporation at 30–35oC. The solid extracts obtained were later prepared into 2.5, 5 and 10 mg/ml. Two millilitres of the solutions were blotted on filter papers, which were dried overnight and placed into jars where adult sandflies were aspirated. Males and females were assayed separately. Results & conclusion: The extracts had significant mortality (p<0.05) in both males and females bioassays but were not significantly different between sexes. The extracts of Acalypha fruticosa and Tagetes minuta had significantly higher mortality rates than those of Tarchonanthus camphoratus and the different concentrations used showed significantly different mortality rates and 10 mg/ml was the most effective concentration. Cent percent mortality was obtained at 96 h of exposure to 5 and 10 mg/ml concentrations except for Tarchonanthus camphoratus which had a mortality of only 46.7% in 10 mg/ml bioassay. These extracts were found to be insecticidal to adult sandflies.