PT-school of Pure and Applied Sciences
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Browsing PT-school of Pure and Applied Sciences by Author "Gicheru, M. M."
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Item Immunological effects of aqueous crude extract from tephrosia purpurea aerial parts on plasmodium berghei infected balb/c mice(2014-07-30) Isindu, Lydia Wanyaga; Gicheru, M. M.Malaria is a serious parasitic disease in the developing world, causing high morbidity and mortality. Plasmodium falciparum, which causes the deadliest form of the disease, has developed resistance to every drug thrown at it and this has kept researchers up at night fighting it. The stem extract of Tephrosia purpurea showed in vitro antiplasmodial activity against the chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. A new prenylated flavone, named terpurinflavone, along with the known compounds lanceolatin A, (- )-semiglabrin and lanceolatin B have been isolated from this extract. The new compound, terpurinflavone, showed the highest antiplasmodial activity. The main objective of this study is to determine the immunological effect of aqueous crude extract from Tephrosia purpurea aerial parts on the immune system of Plasmodium berghei infected BALB/c mice. Highly susceptible BALB/c mice previously infected with Plasmodium berghei isolates that cause malaria in rodents will be used for evaluating the ability of the Tephrosia Purpurea crude extracts to modulate the immune system in the course of murine malaria. Briefly, the groups of mice will be infected with P. berghei and then treated with T purpurea extracts, an already known antmalarial drug candidate, or with Chloroquine, an already known blood stage antmalarial drug or with a saline control. In this study, the parasites will be cultured by parasite passage through 12 BALB/c mice and ultimately infected blood will be harvested from each mouse by cardiac puncture. Subsequently, experimental BALB/c mice will each be injected intraperitoneally with 0.3 ml of the P. berghei-infected murine blood. The groups of mice will then be treated orally with 100, 200 and 400 mg! kg! day of aqueous T purpurea extracts using oral gavage needle for mice, or intraperitoneally with 5mg/kg!day of aqueous Chloroquine, or with O.2ml saline control. Samples will be collected four times in the course of experiment: before infection, after disease development (3 days post infection) but prior to treatment, 4 days post treatment and 12 days post treatment. At every sampling, one drop of blood will be taken from the tail tip of each mouse onto frosted slides for Parasitaemia and leucocytes counts. The slide samples will be air dried and fixed in absolute ethanol then stored in slide boxes till use. Parasitaemia and WBC counts will be done by microscopic enumeration of parasitized RBCs and leukocyte morphology respectively on stained smears. Concurrently, 3 mice will be sacrificed from each cage and blood drawn by cardiac puncture into EDTA-ftlled tubes for IFN-y assay. The blood will be centrifuged at 2000 RPM for 5 minutes to extract plasma which will be stored at -20°C till use. IFN-y in the plasma samples will be measured using mouse IFN-y ELISA kit (Mabtech, AB, Sweden). In a selective manner, this experiment will characterize the levels of IPN-y, WBC and parasitaemia in the peripheral blood samples of the infected mice. This study will provide an insight on the possible role of immune system mechanisms ofthe plant extract in modulating malaria infection. Moreover, it will also attempt to justify its traditional use. Data will be analyzed using ANaVA to compare levels of WBC, parasitaemia and IFN-y across the groups of mice. P values of less than 0.05 will be considered significant.Item Seasonal variation of mosquitoes species (Culicidae), abundance and potential risks to arboviruses in three ecological systems of Marigat District, Baringo County.(2014-07-23) Kabochi, Kamau Samuel; Mueke, J. M.; Gicheru, M. M.; Mwangi, B. M.Livestock and man can be infected with mosquito-borne arboviruses that may result in death. The abundance and vectorial capacity of the mosquito as a vector is dependent on environmental changes such as heavy rains and seasonal flooding that occur in an ecosystem resulting in succession of diverse species and eventual disease epidemics. Some of devastating arboviruses transmitted by mosquitoes are Rift Valley Fever (RVF), West Nile and Chikungunya viruses among others. In Kenya outbreaks of RVF have occurred after every ten years coinciding with the El-Nino rains with most recent one occurring in 200612007 and Yellow Fever during the 1997/1998 El-Nino rains. It is reported that the culpable RVF mosquito vector, Aedes species emerges during the heavy unusual prolonged rain fed floods. The water of Lake Baringo has been swelling over the past one year submerging the shoreline. Geological experts are attributing the rise in water levels and resultant flooding to a rare geological movement of tectonic plates. Unlike the rain fed floods, it is not understood what changes would occur in mosquito composition and infections in such a shoreline ecosystem as that of Lake Baringo currently experiencing such prolonged floods from a swelling waters of the lake. This study aims at establishing changes that would probably occur in vector abundance, species diversity, and infections in the vector, risks and the reservoir to arboviruses in Lake Baringo basin under such circumstances. The current study will be undertaken in three existing ecological systems found in Marigat District:-flooded shoreline of Lake Baringo; riverine swampy wetland; and dry-land ecosystems. The trapping will be carried out in the grazing areas during the day using carbon dioxide baited Centre of Disease Control (CDC) approved light traps as from 3pm to 6pm targeting daytime feeders and as from 6pm to 6am targeting night time feeders. In each of the three identified homesteads, another light trap without CO2 will be placed within the animal shed as from 6pm to 6am to trap night feeders. Therefore a total of 24 traps will be used. Trapped mosquitoes will be identified to genus level in the field, sorted into pools of 50 and then transported to International Livestock Research Laboratory Institute (ILRI), Kenya, for further identification and investigations on the genetic diversity using Intergenetic Site System and micro satellite markers. The infection in mosquitoes (Minimum Infection Rates (MIR» with arboviruses will be determined from homogenized pools by reverse transcript polymerase chain reaction (RT-PCR). Cattle, goats, sheep and chicken will be bred using Ethylene diaminetetra acetic acid (EDTA) coated vacutainer tubes and then alliquaited. Polymerase Chain Reaction (PCR) will be used to determine the Immunoglobulin M (IgM) and Immunoglobulin G (IgG) antibodies to arboviruses. Blood meal analysis will be carried out from the engorged fed trapped mosquitoes to determine reservoir host using Enzyme Linked Immunosorbent Assay (ELISA) and PCR methods. Data will be analysed using Analysis of Variance (ANOVA) to detect differences between low season and high season mosquito numbers with Kendall's statistic used to obtain an index of community similarity. Mosquito diversity will be compared by means of the Shannon diversity index (H'), Shannon evenness measure (E) and Student's t-test