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Orulla AV, Rukunga GM, Chege GM, Kiarie F, Muthaura CN, Githure JI, Kofi-Tsekpo WM. Antimalarial activity of fractions isolated from Albizia gummifera and Aspilia mossambicensis crude extracts. AFRICAN JOURNAL OF HEALTH SCIENCES 1996; 3:44-6. [PMID: 17451297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
To identify the fractions of medicinal plant extracts containing the highest concentration of antimalarial principles, we tested the antimalarial activities of the crude or total extracts and two fractions from Albizia gummifera (Leguminosae) and three fractions from Aspilia mossambicencis (Compositae) against laboratory adapted isolates of Plasmodium falciparum in vitro using the 3H-hypoxanthine uptake assay. Chloroquine was used as a reference antimalarial drug. The mean 50% inhibitory concentrations (IC50s) of A. gummifera total extract and fraction were both <2.2 microg/ml for three P. falciparum isolates while the mean IC50 of A. gummifera f raction-2 was higher (5.0+2.9sd) for the same isolates. Aspilia mossambicensis total extract and fractions-1,4 and 5 had mean IC50 values of 96.6+/-32.5,38.6+/-23.0,142.5+/-79.6 and >1250.0 microg/ml, respectively, against four P. falciparum isolates. These results show that fraction-1 of either A. gummifera or A, mossambicensis had the highest concentration of antimalarial principles. We now plan to concentrate our efforts on these promising fractions in order to isolate pure compounds which could eventually be used to effectively treat malaria.
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Anjili CO, Mbati PA, Mwangi RW, Githure JI, Koech DK. A simple method for maintaining, detecting and recovering virulent Leishmania donovani in hamsters. Acta Trop 1996; 60:263-7. [PMID: 8659325 DOI: 10.1016/0001-706x(95)00129-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The ability of hamsters (Mesocricetus auratus) to retain amastigotes of Leishmania donovani at cutaneous sites was examined. Following intradermal inoculation of L. donovani stationary phase culture promastigotes in fore and hind footpads, nasal area and belly skin, cultures of aspirates taken fortnightly from these sites showed that amastigotes can survive in the skin for up to 10 months without visceralizing. Hairless cutaneous sites were better at retaining L. donovani amastigotes than the hairy belly skin. L. donovani promastigotes cultivated from aspirates of sites of inoculation were highly virulent. The skin is suggested as one of the sites where viscerotropic L. donovani can remain cryptic for a long time before the infection either visceralizes or is aborted. Skins of hamsters when inoculated intradermally can serve as an easy site for maintaining, detecting and recovering virulent L. donovani without killing the hamster.
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Ingonga P, Mbati PA, Anjili CO, Mutani A, Wishitemi B, Odongo S, Robert LL, Githure JI. The effect of immune sera from hamsters immunized with sandfly gut and whole body extract antigens on the fecundity and mortality of Phlebotomus duboscqi (Diptera: Psychodidae). Acta Trop 1996; 60:269-79. [PMID: 8659326 DOI: 10.1016/0001-706x(95)00132-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Phlebotomus duboscqi were fed on hamsters previously immunized with different concentrations of homogenized crude sandfly gut antigen and supernatant obtained from whole body extract. The humoral response in the rodents was quantified at different times post-immunization by the enzyme-linked immunosorbent assay. Sandflies were fed on either immunized or saline control hamsters and the effect of the blood meals on sandfly feeding, survival and fecundity was investigated. The humoral response in immunized hamsters as measured by the presence of P. duboscqi-specific IgG antibodies was significantly greater (P < 0.05) as compared to the controls. This difference was noted in sera collected on 15 and 25 days post-immunization. Sandflies fed on immunized hamsters had a significantly higher mortality (P < 0.05) and decreased egg production (P < 0.05) than those fed on unimmunized control hamsters.
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Githure JI, Ngumbi PM, Anjili CO, Lugalia R, Mwanyumba PM, Kinoti GK, Koech DK. Animal reservoirs of leishmaniasis in Marigat, Baringo District, Kenya. EAST AFRICAN MEDICAL JOURNAL 1996; 73:44-7. [PMID: 8625862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A total of 1128 rodents belonging to seven genera were examined for leishmanial parasites over a period of sixteen months. Parasites were isolated from 36 (12.5%) Tatera robusta, 3 (0.5%) Arvicanthis niloticus, and 2 (0.8%) Mastomys natalensis. All isolates were characterised by isoenzyme analysis using nine enzymes. The enzymes examined were: malate dehydrogenase (MDH), phosphoglucomutase (PGM), glucose phosphate isomerase (GPI), isocitrate dehydrogenase (ICD), nucleoside hydrolase (NH), glucose 6-phosphate dehydrogenase (G6PD), mannose phosphate isomerase (MPI), malic enzyme (ME) and 6-phosphogluconate dehydrogenase (6PGD). The enzyme profiles from these isolates were compared with those from Leishmania reference strains and also with isolates of Leishmania major from man and sandfly, P. duboscqci from the same area. All the isolates except one from a Mastomys were identified as L. major. The isolate from Mastomys was trypanosome-like and remains unidentified. The results in this study show that Tatera robusta is the main reservoir of cutaneous leishmaniasis in Baringo District. None of the animals trapped were found infected with Leishmania donovani suggesting that rodents do not play a role in the transmission of visceral leishmaniasis in this area.
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Copeland RS, Walker TW, Robert LL, Githure JI, Wirtz RA, Klein TA. Response of wild Anopheles funestus to repellent-protected volunteers is unaffected by malaria infection of the vector. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 1995; 11:438-440. [PMID: 8825504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A field experiment was conducted to compare the biting behavior of Plasmodium falciparum-infected and uninfected Anopheles on humans using mosquito repellents. Repellent formulations (5% [wt/vol] N,N-diethyl-3-methylbenzamide [deet] or 5% [wt/vol] AI3-37220, a piperidine compound, both in 100% ethanol, or 100% ethanol alone [as a control]) were applied to the lower legs of 3 collectors in each of 4 houses. Collectors caught mosquitoes over 6 collection nights. Mosquitoes were collected into vials after they initiated probing on the leg of a collector. Infected females made up the same proportion of the Anopheles funestus populations biting either repellent-protected or unprotected individuals. We conclude that repellent formulations are equally effective against Plasmodium-infected and uninfected An. funestus.
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Olobo JO, Anjili CO, Gicheru MM, Mbati PA, Kariuki TM, Githure JI, Koech DK, McMaster WR. Vaccination of vervet monkeys against cutaneous leishmaniosis using recombinant Leishmania 'major surface glycoprotein' (gp63). Vet Parasitol 1995; 60:199-212. [PMID: 8747903 DOI: 10.1016/0304-4017(95)00788-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Vervet monkeys (Cercopithicus aethiops) were shown to give a positive delayed-type hypersensitivity (DTH) reaction to gp63, a major surface glycoprotein of Leishmania parasites, and also produce antibodies to the molecule following a triple vaccination with a total dose of 150 micrograms of recombinant gp63 mixed with Bacille Calmette Guerin (BCG). However, peripheral blood leucocytes (PBL) from these animals neither proliferated nor produced any interferon-gamma (IFN-gamma) following in vitro stimulation with the antigen. Analysis of lymphocyte subsets following vaccination did not reveal any striking phenotypic alteration of cellular sub-populations in PBL. When vaccinated animals were rechallenged, via the needle, with virulent Leishmania major promastigotes containing salivary gland extracts from vector sandflies, only partial protection was achieved. We concluded from these studies that rgp63 produced in Escherichia coli is a safe vaccine molecule which gives only partial protection following vaccination in the vervet monkey host. The molecule requires further improvement for vaccine and/or immunodiagnosis application.
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Anjili CO, Mbati PA, Mwangi RW, Githure JI, Olobo JO, Robert LL, Koech DK. The chemotactic effect of Phlebotomus duboscqi (Diptera: Psychodidae) salivary gland lysates to murine monocytes. Acta Trop 1995; 60:97-100. [PMID: 8610544 DOI: 10.1016/0001-706x(95)00112-r] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The possibility that salivary gland lysates of Phlebotomus duboscqi are able to attract vertebrate monocytes was investigated. In vitro studies showed that salivary gland lysates of P. duboscqi, the vector of Leishmania major in Kenya, are chemotactic to mouse peritoneal monocytes. This attraction of monocytes by vector salivary gland lysates may form part of the mechanisms through which sandfly saliva ensures successful parasitization of macrophages in a susceptible host by Leishmania parasites.
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Mbati PA, Anjili CO, Lugalia R, Mwanyumba P, Tonui WK, Robert LL, Githure JI. Experimental immunization against cutaneous leishmaniasis using Leishmania major subcellular fractions alone or in combination with Phlebotomus duboscqi gut antigens. EAST AFRICAN MEDICAL JOURNAL 1995; 72:519-522. [PMID: 7588148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Leishmania major-derived flagella and nuclear fractions, and a combination of flagella and sand fly gut antigens were assessed for protection against L. major infection in BALB/c mice. Mice immunized with flagella antigen developed a severe infection while nuclear fraction-immunized animals were partially protected at the onset of infection from week 1 to 4 post challenge. A combination/cock tail of flagella and sand fly gut antigens protected animals at a later stage from week 10 to 14 post-infection. Surviving cocktail-immunized animals did not ulcerate, and parasites did not metastasize to the viscera. These results provide preliminary evidence of the potential of a cock tail antigen derived from Leishmania flagella and sand fly gut in the protection against cutaneous leishmaniasis caused by L. major.
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Mbogo CN, Snow RW, Khamala CP, Kabiru EW, Ouma JH, Githure JI, Marsh K, Beier JC. Relationships between Plasmodium falciparum transmission by vector populations and the incidence of severe disease at nine sites on the Kenyan coast. Am J Trop Med Hyg 1995; 52:201-6. [PMID: 7694959 DOI: 10.4269/ajtmh.1995.52.201] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The transmission of Plasmodium falciparum was studied in relation to the incidence of severe malaria infections at nine sites in the Kilifi District in Kenya. Intensive mosquito sampling during a one-year period yielded Anopheles gambiae s. l., An. funestus, An. coustani, An. squamosus, An. nili, and An. pharoensis. Anopheles gambiae s.l. was the predominant vector, comprising 98.4% of the total anophelines collected. Overall, 3.5% of 2,868 An. gambiae s.l. collected indoors and 0.8% of 261 collected outdoors contained P. falciparum sporozoites. Transmission was detected during 10 months, with peak periods from June to August and December to January. In eight of the nine sites, entomologic inoculation rates (EIRs) averaged only four infective bites per year (range 0-18); an annual EIR of 60 was measured for the site with the highest intensity of transmission. The incidence of severe malaria infections, ranging from 8.6 to 38.1 per 1,000 children (0-4 years), was not associated with EIRs. At these sites on the coast of Kenya, a high incidence of severe disease occurs under conditions of very low levels of transmission by vector populations. With respect to conventional approaches for vector control in Africa, decreases in transmission, even to levels barely detectable by standard approaches, may not yield corresponding long-term reductions in the incidence of severe disease.
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Ofulla AO, Orago AS, Githure JI, Burans JP, Aleman GM, Johnson AJ, Martin SK. Determination of fifty percent inhibitory concentrations (IC50) of antimalarial drugs against Plasmodium falciparum parasites in a serum-free medium. Am J Trop Med Hyg 1994; 51:214-8. [PMID: 8074255 DOI: 10.4269/ajtmh.1994.51.214] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Plasmodium falciparum chemosensitivity to the various antimalarial drugs is presently determined in the laboratory by setting up multiple microcultures of the parasite and estimating the amount of growth inhibition caused by known concentrations of drug. Parasite growth inhibition is assessed either by microscopy, radiolabeled substrate uptake, or calorimetrically. The obligate requirement for serum in this assay presents difficulties in the direct comparison of results among laboratories. We now have evidence that antimalarial drug sensitivity assays can be reliably performed in a serum-free medium. The overall comparison of 50% inhibitory concentration (IC50) values obtained with serum-free media (bovine albumin, Cohn fraction V [BAM] and BAM combined with glucose and lipids-cholesterol-rich mixture) and those obtained in serum-supplemented medium was r = 0.56; n = 60; P < 0.01.
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Anjili CO, Olobo JO, Mbati PA, Robert L, Githure JI. Experimental infection of domestic goats with Leishmania major through bites of infected Phlebotomus duboscqi and needle inoculation of culture-derived promastigotes. Vet Res Commun 1994; 18:301-5. [PMID: 7831760 DOI: 10.1007/bf01839197] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Kurtzhals JA, Hey AS, Jardim A, Kemp M, Schaefer KU, Odera EO, Christensen CB, Githure JI, Olafson RW, Theander TG. Dichotomy of the human T cell response to Leishmania antigens. II. Absent or Th2-like response to gp63 and Th1-like response to lipophosphoglycan-associated protein in cells from cured visceral leishmaniasis patients. Clin Exp Immunol 1994; 96:416-21. [PMID: 8004810 PMCID: PMC1534582 DOI: 10.1111/j.1365-2249.1994.tb06044.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The T cell response to different Leishmania donovani antigens was investigated using peripheral blood mononuclear cells (PBMC) from Kenyans cured of visceral leishmaniasis and non-exposed Danes. Crude promastigote and amastigote antigens both induced proliferation and interferon-gamma (IFN-gamma) production in PBMC from cured patients, while cells from non-exposed donors gave weak responses. A similar pattern was induced by lipophosphoglycan-associated protein (LPGAP). By contrast, the major surface protease of Leishmania, gp63, induced only a weak proliferative response without IFN-gamma production in five of 17 samples from cured patients. Four of the five responding cultures produced IL-4, i.e. the response to this antigen was of the Th2 type. Furthermore, sera from acutely ill visceral leishmaniasis patients contained high levels of IgG antibodies to gp63. The Th2-like response to gp63 in patients cured of visceral leishmaniasis differs from the Th1-like response to the same antigen observed in patients cured of cutaneous leishmaniasis.
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Ofulla AV, Okoye VC, Khan B, Githure JI, Roberts CR, Johnson AJ, Martin SK. Cultivation of Plasmodium falciparum parasites in a serum-free medium. Am J Trop Med Hyg 1993; 49:335-40. [PMID: 8396859 DOI: 10.4269/ajtmh.1993.49.335] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The elimination of serum from Plasmodium falciparum culture media could decrease costs, enhance procurement, and improve the feasibility of large-scale production of parasite material. We provide a semi-defined, serum-free formulation, of commercially available constituents that supports P. falciparum parasite growth at rates comparable with those obtained with serum-supplemented media. The medium is composed of RPMI 1640 to which HEPES, extra glucose, bicarbonate, and hypoxanthine have been added. Bovine albumin and serum-derived, lipids-cholesterol-rich mixture are then used in place of serum.
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Mbogo CN, Glass GE, Forster D, Kabiru EW, Githure JI, Ouma JH, Beier JC. Evaluation of light traps for sampling anopheline mosquitoes in Kilifi, Kenya. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 1993; 9:260-263. [PMID: 8245934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Anopheline mosquitoes were sampled inside houses, where residents slept under untreated bednets, by CDC light traps and human-biting catches to evaluate light traps as a means for determining human exposure to malaria vectors in Kilifi District, Kenya. Mosquitoes were sampled during 2 all-night collections by light traps and one all-night biting catch in a series of 262 houses. Collections yielded 1,721 Anopheles gambiae s.l. and 46 An. funestus, and 60.3% of the houses were negative for anophelines. There was a significant correlation in numbers of An. gambiae s.l. captured by light traps and human-biting collections (r = 0.64), but light traps were biased and underestimated An. gambiae s.l. abundance. This bias increased with increasing mosquito abundance. In addition, the proportion of An. gambiae s.l. infected by Plasmodium falciparum was 2.3-fold higher in light traps than in human-biting collections. Along the coastal zone of Kenya where vector abundance is low, light traps do not provide an adequate estimate of man-vector contact when such information is required at the household level in epidemiological studies of malaria parasite transmission.
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Mbogo CN, Snow RW, Kabiru EW, Ouma JH, Githure JI, Marsh K, Beier JC. Low-level Plasmodium falciparum transmission and the incidence of severe malaria infections on the Kenyan coast. Am J Trop Med Hyg 1993; 49:245-53. [PMID: 8357087 DOI: 10.4269/ajtmh.1993.49.245] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The transmission of Plasmodium falciparum was studied in relation to the incidence of severe malaria infections at Sokoke and Kilifi town, Kilifi District, Kenya. Intensive mosquito sampling during a one-year period yielded Anopheles gambiae s.l., An. funestus, and An. coustani. Anopheles gambiae s.l. was the predominant vector, comprising 87.9% and 97.9% of the total anophelines collected in Sokoke and Kilifi town, respectively. The proportion of An. gambiae s.l. with P. falciparum sporozoite infections was 4.1% (20 of 491) in Sokoke and 2.2% (3 of 138) in Kilifi town; no infections were detected in An. funestus or in An. coustani. Entomologic inoculation rates indicated that residents were exposed to only 8.0 infective bites per year in Sokoke and 1.5 in Kilifi town. Transmission was detected during only six months in Sokoke and three months in Kilifi town despite low-level, year-round vector activity. The yearly incidence of severe P. falciparum infections in children, 1-4 years of age was 24.1 per 1,000 in Sokoke and 4.2 per 1,000 in Kilifi town. Monthly patterns of transmission corresponded closely with the incidence of severe infections. At these sites on the coast of Kenya, the spatial and temporal incidence of severe malaria infections is associated with low-level P. falciparum transmission by vector populations.
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Okong'o-Odera EA, Wamachi A, Kagai JM, Kurtzhals JA, Githure JI, Hey AS, Were JB, Koech DK, Mitema ES, Kharazmi A. Field application of an ELISA using redefined Leishmania antigens for the detection of visceral leishmaniasis. Trans R Soc Trop Med Hyg 1993; 87:423-4. [PMID: 8249071 DOI: 10.1016/0035-9203(93)90023-j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Two soluble antigens from Leishmania donovani of 116 kDa and 70 kDa molecular mass, and a soluble mixture of crude antigens, were used in an enzyme-linked immunosorbent assay (ELISA) for the detection of visceral leishmaniasis (VL) in the field, and compared with the direct agglutination test (DAT). The tests were carried out on 8 VL patients, 34 normal individuals from an area endemic for the disease, and 68 former visceral leishmaniasis patients 1-5 years after treatment. The 70 kDa ELISA and the DAT had a sensitivity and specificity of 100% (95% confidence interval 63-100%), while the 116 kDa ELISA and the soluble crude antigen ELISA were 37.5% (9-76%) and 50% (16-84%) sensitive, respectively. When using ELISA (116 kDa or 70 kDa), 68-69% of sera tested 1-2 years, and 92-94% of sera tested 5 years, after treatment were negative. In contrast, when DAT or ELISA with crude antigen were used, the negativity rate was 31% 1-2 years, and 53% 5 years, after treatment. DAT was therefore not an accurate test for diagnosis in the field. The use of the 70 kDa antigen in ELISA was an accurate alternative to DAT in the detection of VL.
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Mbati PA, Anjili CO, Mwaniki-Kagai J, Githure JI. Giemsa and acridine orange stains: a laboratory experience in the diagnosis of leishmaniasis--short communication. EAST AFRICAN MEDICAL JOURNAL 1993; 70:466-7. [PMID: 8293711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Mbogo CN, Kabiru EW, Muiruri SK, Nzovu JM, Ouma JH, Githure JI, Beier JC. Bloodfeeding behavior of Anopheles gambiae s.l. and Anopheles funestus in Kilifi District, Kenya. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 1993; 9:225-227. [PMID: 8350080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Blood meal samples were tested by ELISA for 534 Anopheles gambiae s.l. and 76 Anopheles funestus collected from 25 sites in Kilifi District, Kenya. Human IgG was detected in 94.4% of the An. gambiae s.l. and in 90.8% of the An. funestus. No samples were positive for cow and only a few were positive for goat. Both species fed predominantly on humans irrespective of host availability. At these sites on the Kenyan coast, the high degree of human-feeding by malaria vectors contributes to the efficiency of malaria parasite transmission and the high incidence of severe malaria.
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Anjili CO, Githure JI. Refractoriness of domestic cats to infection with a Kenyan strain of Leishmania donovani. EAST AFRICAN MEDICAL JOURNAL 1993; 70:322. [PMID: 8306914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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45
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Taylor KA, Paskewitz SM, Copeland RS, Koros J, Beach RF, Githure JI, Collins FH. Comparison of two ribosomal DNA-based methods for differentiating members of the Anopheles gambiae complex (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 1993; 30:457-461. [PMID: 8096250 DOI: 10.1093/jmedent/30.2.457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Two DNA-based methods, the restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR), were used to identify mosquitoes of the Anopheles gambiae Giles complex collected in Kenya. Field-collected specimens of An. gambiae, An. arabiensis Patton, and An. merus Donity were tested. From a sample of 208 mosquitoes, 181 (87%) were identified by the RFLP method and 205 (99%) were identified by the PCR method. There was complete concordance between the two methods with regard to species identification. PCR assays were simpler, faster, and more reliable than RFLP assays.
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Olobo JO, Reid GD, Githure JI, Anjili CO. IFN-gamma and delayed-type hypersensitivity are associated with cutaneous leishmaniasis in vervet monkeys following secondary rechallenge with Leishmania major. SCANDINAVIAN JOURNAL OF IMMUNOLOGY. SUPPLEMENT 1992; 11:48-52. [PMID: 1514049 DOI: 10.1111/j.1365-3083.1992.tb01618.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
IFN-gamma levels and delayed-type hypersensitivity (DTH) responses were evaluated in vervet monkeys, following secondary infection with Leishmania major (L. major). The animals had previously been vaccinated with leishmanial antigen, exposed to a primary infection and allowed to self-cure. Supernatants of peripheral blood mononuclear cell (PBMC) cultures, stimulated with either L. major antigen or Concanavalin A (Con A), were examined for the presence of IFN-gamma in a double sandwich enzyme-linked immunosorbent assay (ELISA). Significant levels of IFN-gamma were detected during active disease and following self-cure in both antigen and Con A supernatants. Higher levels of IFN-gamma were, however, present during active disease as compared with after self-cure. Positive and strong DTH responses were elicited in all experimental animals, following intradermal injection of fixed promastigotes (5 x 10(7)/animal) before rechallenge, during active infection and following self-cure. Again, strongest DTH responses were obtained during active infection as compared with the other sampling points. There was a correlation between IFN-gamma levels and DTH responses. It was concluded that IFN-gamma secretion and positive DTH responses are associated with secondary L. major infection and represent specific immunological correlates of protection in this disease model.
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47
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Koech DK, Olobo JO, Wamachi A, Githure JI, Reid GD. Cellular responses of vervet monkeys (Cercopithecus aethiops) experimentally infected with Leishmania major. J Med Primatol 1992; 21:375-6. [PMID: 1307757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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48
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Khan B, Ofulla AV, Kariuki DM, Githure JI, Kabiru EW, Martin SK. Drug sensitivity studies during a highland malaria epidemic in Kenya. Trans R Soc Trop Med Hyg 1992; 86:371-2. [PMID: 1440805 DOI: 10.1016/0035-9203(92)90222-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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49
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Ogutu RO, Oloo AJ, Ekissa WS, Genga IO, Mulaya N, Githure JI. The effect of participatory school health programme on the control of malaria. EAST AFRICAN MEDICAL JOURNAL 1992; 69:298-302. [PMID: 1505412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two hundred primary level school children, aged between 7 and 18 years took part in a comparative pilot study of the effect of participatory school health education in Kisumu, Western Kenya in 1988. An experimental cohort of 100 pupils had participatory health education versus a passive control of another 100. An initial KAP survey revealed comparable sociological variables as well as morbidity statistics. No significant change occurred on the knowledge of the disease between the groups after 3 months. However, positive change in attitude here determined by positive antimalarial practices, was observed more frequently in the experimental group than in the control group. Efforts to environmental manipulation increased by 69% vs 1%, while parasite rates decreased by 32% vs an increase of 5%, respectively. Similarly there was a decrease in absenteeism of 25% vs an increase of 5% between the groups. Clinical malaria was reported less frequently in the experimental group than the control (26% against 8%). In conclusion, this pilot study suggests that participatory approach in effective health education to school children should be investigated further to determine its potential in the intersectoral malaria control strategy.
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Kurtzhals JA, Hey AS, Theander TG, Odera E, Christensen CB, Githure JI, Koech DK, Schaefer KU, Handman E, Kharazmi A. Cellular and humoral immune responses in a population from the Baringo District, Kenya to Leishmania promastigote lipophosphoglycan. Am J Trop Med Hyg 1992; 46:480-8. [PMID: 1575296 DOI: 10.4269/ajtmh.1992.46.480] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In a cross-sectional house-to-house study in a leishmaniasis-endemic area in Kenya, the cellular and humoral immune response to Leishmania lipophosphoglycan (LPG) was determined. Clinical data, peripheral blood mononuclear cells, and plasma were obtained from 50 individuals over the age of eight years. Lymphoproliferation and interferon-gamma (IFN-gamma) production by these cells were examined. It was shown that cells from all six individuals in the population with a history of kala-azar responded to LPG in the lymphocyte proliferation assay, and four of these six responded in the IFN-gamma assay. In contrast, cells from 12 of 44 individuals from the study area with no history of kala-azar and none of the five Danish control samples responded to LPG. Antibodies against LPG were detected by enzyme-linked immunosorbent assay in 45 of 50 plasma samples. Our findings clearly show that mononuclear cells from kala-azar patients cured of infection were able to respond to the LPG preparation. The finding of a specific cellular immune response to LPG in 12 of 44 individuals with no history of kala-azar is consistent with previous epidemiologic studies, in which it has been shown that a proportion of L. donovani infections run a subclinical course. The high frequency of individuals with antibodies against LPG might indicate that a majority of the population had been exposed to the parasite.(ABSTRACT TRUNCATED AT 250 WORDS)
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