Browsing by Author "Ouma, J.O."
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Item Changes in classical pathway complement activity in dromedary camels experimentally infected with Trypanosoma evansi(1997) Ouma, J.O.; Olaho-Mukami, W.; Wishitemi, B.E.L.; Guya, S.O.; Kenya Trypanosomiasis Research Institute; Division of Biochemistry and Immunology, Kenya Trypanosomiasis Research Institute, P.O. Box 362, Kikuyu, Kenya Department of Zoology, Moi University, P.O. Box 1125, Eldoret, KenyaThe complement system is known to have important effector functions in immune responses. However, its role in camel trypanosomosis has not been detennined. The present study was undertaken to evaluate haemolytic complement activity in Trypanosoma evansi-infected and uninfected camels. Five dromedary camels were experimentally infected with T. evansi and classical pathway haemolytic complement activity was assayed. Parasitaemia and packed cell volume were also monitored. Following infection, classical pathway haemolytic complement showed a slight initial increase (7%) in all the camels. The amounts later dropped as the infection progressed and correlated negatively with parasitaemia. Haemolytic complement recovered following elimination of trypanosomes by treatment with melarsomine. Treatment of uninfected camels had no effect on complement. This study has demonstrated that complement concentration increases in the initial phase of infection followed by a drop as the infection progresses towards chronicity. In addition, the study has shown that activation of the classical complement pathway occurs in camels infected with T. evansi. Complement could therefore be involved in the in vivo control of parasitaemia in dromedary camels infected with T. evansi. Decreased complement levels in this species could lead to immunosuppression, widely reported in animal trypanosomosis.Item The Influence of Temporal and Seasonal Changes on Genetic Diversity and Population Structure of Thee Tsetse Fly, Glossina Pallidipes in Kenya(2010) Ouma, J.O.; Krafsur, E.S.; Kenya Trypanosomiasis Research Institute; Kenya Agricultural Research Institute (TRC); USPSH-NIH grans AI- 524560, International Atomic Energy(IAEA)The Tsetse fly. Glossina pallidipes. (Diptera: Glossinidae) is an important vector of animal trypanosomiasis It has also been implicated in the transmission of pathogens that cause human AfricanTrypanosomiasis. Understanding how C. pallidipes populations vary temporally is necessary for effective intervention. Temporal variation in allele frequencies at eight microsatellite loci was assessed by sampling local populations of C. pallidipes. Samplings were carried out in 2000, 200 I, and 2003 in the Lambwe Valley and Nguruman areas in Kenya. Six polymorphic loci were scored. ABele frequencies were homogenous between seasons. Genetic differentiation was higher among dry season samples (F, r = 0.051, C" = 0.047) than wetseason samples (F" = 0.041, C" = 0.037). Differentiation between pooled dry season and pooled wet season samples did not differ (F; r = 0.008, C" = 0.004). Analysis of variance revealed no substantial genetic subdivision in seasons or years. It is concluded that C. pallidipes populations are more aggregated during the dry season, resulting in stronger measures of genetic differentiation when compared with wet seasons. However, season and time had no effect, indicating relative stability of C. pallidipes populations. Thus, strategies for suppression of G. pallidipes in the country should adopt measures that may not reduce effectiveness in different times of the year.Item Prevalence of trypanosomosis in camel calves: A pilot study in laikipia District of Kenya(2000) Njiru, Z. K.; Ole-Mapeny, I.M.; Ouma, J.O.; Ndungu, M.J.; Olaho-Mukami, W.; Kenya Trypanosomiasis Research Institute; Kenya Trypanosomiasis Research Institute, LIRI (Uganda)Trypanosomosis is one of the most important diseases affecting camel calves. It presents itself as an acute form and is usually fatal if treatment is not carried out. A study was initiated at Mogwooni ranch in Laikipia District of Kenya to survey the prevalence of trypanosomosis in camel calves of mixed breeds, and to evaluate the microhematocrit centrifugation technique (MHCT), monoclonal antibody based card latex agglutination test (Suratex®), wet smear and mouse inoculation (MI) in the diagnosis of the disease in camels. The tests were assessed for a period of 16 months. Mean Trypanosoma evansi prevalence ranged from 4.5% as determined by the wet smear, 11.1 % by MHCT, and 14.6% by MI, to 28.3% by Suratex®. Young calf death rate due to trypanosomosis was 12.3%, while overall mortality was 15%. The cost of veterinary care (anthelmintics, acaricides and trypanocldes) was on average US$4.6 per calf per year. It is thus recommended that diagnosis accompanied by proper treatment be carried out routinely for the survival of camel calves in trypanosomosis endemic areas.Item Sensory Evaluation of Quality Protein Maize in Kenya(2012) Ouma, J.O.; De Groote, H. ; Gunaratna, N.S.; Kenya Agricultural Research InstituteThe paper analyses sensory attributes and acceptability of KH631Q and WSQI04, Quality Protein Maize varieties (QPM) and H513 and Embu Composite (EMCO) conventional varieties in the preparation of local food, githeri. KH631Q and H513 are commercial hybrids, while WSQI04 and EMCO are Open Pollinated Varieties (OPVs). The evaluations were conducted in November and December 2007 in one rural and two urban communities in Embu district, Eastern Kenya. 131 participants evaluated samples of each of the four treatments that were presented in randomized order, generated through a balanced design. The samples were evaluated on a Likert scale of I (very poor) to 5 (very good) on three attributes namely appearance, taste and texture. Overall score of the samples was also done. Ordinal regression model was used to analyse the data. There were differences (P<0.05) in the sensory attributes of the samples. Samples of WSQ 1 04 were more preferred to H513, the control. There were no differences in preferences between men and women. Similarly, preferences for the samples did not vary by age. Appearance, taste, and texture were all important in determining the overall evaluation. The study suggests that evaluation by an expert panel to explore more detailed criteria be done. It further suggests that conventional varieties should be compared with their QPM converted counterpart where possible to isolate the effect of QPM.Item Structure of some East African Glossina fuscipes fuscipes populations(2008) Krafsur, E.S.; Marquez, J.G.; Ouma, J.O.; Kenya Trypanosomiasis Research Institute; Department of Entomology, Iowa State University, Ames, Iowa, U.S.A.,Glossinafuscipesfuscipes Newstead 1910 (Diptera: Glossinidae) is the primary vector of human sleeping sickness in Kenya and Uganda. This is the first report on its population structure. A total of 688 nucleotides of mitochondrial ribosomal 16S2 and cytochrome oxidase I genes were sequenced. Twenty-one variants were scored in 79 flies from three geographically diverse natural populations. Four haplotypes were shared among populations, eight were private and nine were singletons. The mean haplotype and nucleotide diversities were 0.84 and 0.009, respectively. All populations were genetically differentiated and were at demographic equilibrium. In addition, a long standing laboratory culture originating from the Central African Republic (CAR-lab) in 1986 (or before) was examined. Haplotype and nucleotide diversities in this culture were 0.95 and 0.012, respectively. None of its 27 haplotypes were shared with the East African populations. A first approximation of relative effective population sizes was Uganda> CAR-lab> Kenya. It was concluded that the structure of G. f fuscipes populations in East Africa is localized.Item Use of Suratex for Field Diagnosis of Patent and Non-Patent Trypanosoma Evansi infections in Camels(1996) Olaho-Mukani, W.; Nyang'oa, J.M.N.; Ouma, J.O.; Kenya Trypanosomiasis Research Institute; Kenya Trypanosomiasis Research Institute, (KIRTI)Recent development of sensitive immunoassay techniques for the detection of circulating trypanosomal antigens has significantly improved the diagnosis of both animal and human trypanosomosis (Rae & Luckins, 1984;Nantulya, 1989; Nantulya el al., 1992; Olaho-Mukani, 1989). This is because these tests are diagnostically more sensitive than parasitological tests, and the detection of antigens in the peripheral circulation is a more reliable indication of active infection (Voller & De Savigny, 1981). They are also ideal for the evaluation of chemotherapeutic response, because, after effective treatment, trypanosomal antigens disappear from the circulation (Olaho-Mukani et al., 1992), until recently, however, trypanosomal antigen detection tests were limited to laboratory use only. The introduction of card latex agglutination tests for the field diagnosis of animal and human trypanosomosis (Nantulya, 1993, 1994) is expected to overcome this obstacle. In the present study, a commercial kit (Suratex, Brentec Diagnostics, Nairobi) was used to conduct a recently introduced latex agglutination test (Nantulya, 1994), for the evaluation of chemotherapeutic response and diagnosis of. Typanosoma evansi infection in camels.
