Browsing by Author "Kariuki, D.P."
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Item Characterisation of Theileria parva isolates from Kiambu district, Kenya(2004) Matete, G.O.; Kanyari, P.W.N.; Ngatia,T.A.; Kariuki, D.P.; Ndungu, S.; University of Nairobi National Veterinary Research Centre Muguga P.O Box 32 KikuyuFour Theileria parva isolates from Muguga area of Kiambu district, Kenya, were used to establish schizont-infected cell lines. Their protein antigenswere then separated by sodium dodecyl sulphate polyacrylamide gelelectrophoresis (SDS page). The isolates were subsequently subjected to protein analysis and characterization by the western immunoblotting technique. Probing for the polymorphic immunodominant molecule (PIM) was done using monoclonal antibody no. 4. SDS page detected up to 20 protein antigens of molecular mass 35,000-180,OOODa. The western blot analysis revealed a greater heterogeneity in the molecular mass (Mr) of PIM than previously thought. The Mr of PIM varied between 80 and 90 kDa. The isolates further revealed different densities of surface epitopes with variable reaction to the monoclonal antibody. The implications of these findings to the epidemiology of east coast fever and immunisation programmes are discussed.Item Confined field trial of a double recombinant vaccinia-rinderpest vaccine in Kenya: I. Determination of the minimum immunising dose in African Zebu cattle(1966) Wamwayi, H.M.; Ondedo, V.O.; Wafula, J.S.; Kariuki, D.P.; Yilma,T.; KARI - National Veterinary Research Centre Muguga P.O BOX 32 KIKUYU Kenya Agricultural Research Institute Headquarters P.O BOX 57811 Nairobi School of veterinary Medicine University of CalifoniaTwenty cattle vaccinated with doses ranging between 103 pfu and 107 pfu of a double recombinant vaccinia-rinderpest vaccine expressing the fusion (F) and haemagglutinin (H) proteins of rinderpest virus, were challenged after 28 days with a lethal dose of the virulent Kabete '0' strain of rinderpest virus. All animals vaccinated with 105, 106 and 107 pfu of the recombinant virus were fully protected against clinical signs of rinderpest. One of four cattle in each of the groups vaccinated with 103 or 104 pfu and five unvaccinated control animals developed clinical signs of the disease and died within 8-16 days of challenge. All surviving cattle vaccinated with 107 pfu of the recombinant virus did not develop anamnestic antibody responses following challenge while two out of four animals vaccinated with 106 pfu and all those vaccinated with 105 pfu or less developed anamnestic responses of four-fold or greater. The results indicated the potential value of the double recombinant vaccinia-rinderpest vaccine for immunising cattle in the field.Item Cross-immunity studies using Kenyan stocks of Cowdria ruminantium(1966) Rumberia, R.M.; Ngumi, P.N.; Mbogoh, S.K.; Kariuki, D.P.; Gitau, P.K.; KARI (National Veterinary Research Centre Muguga)Heart water or cowdriaosis, caused by the rickettsia organism Cowdria ruminantium, is a disease of major economic importance in sub-Saharan Africa (Ui1enberg 1983). The disease affects domestic and wild ruminants and is transmitted trans-stadially by ticks of the genus Amblyomma. The disease is controlled by control of vector ticks through use of acaricides, treatment of sick animals or by vaccination using an infection and treatment method. The first practical vaccination approach was investigated by Neitz and Alexander (1941) using Cowdria infected sheep blood. The infection and treatment method is used because animals that recover from clinical disease are usually resistant to homologous and in most cases to heterologous challenge (Uilenberg et al 1983). There are however, same shortcomings with this method.Item Immunisation against East Coast Fever: Possible ways of reducing costs(1995) Kariuki, D.P. ; Mbogo, S.K.East Coast fever (ECF) is lymphoproliferative disease of cattle caused by protozoan parasite, Theileria parva (Theiler, 1904) and ransmittes transtafially by a three-host tick, Rhipicephalus appendiculatus (Irvin and Morrison, 1987). Due to its high mortality and morbidity rates (Irvin and Morrison, 1987), the high costs of controlling the vector rick (Kariuki, 1990) and the high cost of the chemotherapeutic drugs (Mutugi, 1988), it is of major economic importance (Mukhebi, 1992).Item Immunisation Of Small-Holder Cattle Against East Coast Fever In Kiambu District, Kenya(1994) Linyonyi, J.M.; Kariuki, D.P.; Rumberia, R.M.; Mbogo,S.K.; Linyonyi, A.; KARI ( National Veterinary Research Centre P.o Box 32 kikuyu )Three hundred and fifty-eight head of cattle were immunized against East Coast fever using the 'infection and treatment method' in small holdings in Kiambu District. It was observed that the animals could be successfully monitored once every 3 days instead of daily as was done previously. The reaction rate was higher in calves than in adults; thet incidence of other tick-borne diseases did not: increase after immunization despite a relaxation in’ tick control efforts.Item Isolation of the Causative Agent of Heartwater (Cowdria ruminantium) from Three Amblyomma Species in Eight Districts of Kenya.(British Veterinary Association , 1997) Ngumi, P.N.; Rumberia, R.M.; Williamson, S.M.; Sumption, K.J.; Lesan, A.C.; Kariuki, D.P.; National Veterinary Research Centre; University of Edinburgh; 1.Centre for Tropical Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG 2.National Veterinary Research Centre, Box 32, Kikuyu, KenyaThirteen isolates of Cowdria ruminantium were made from eight different Districts of Kenya by four different isolation methods. Feeding adult Amblyomma species ticks derived from nymphs collected in the field and the inoculation of homogenates prepared from adult field ticks had the highest success rate. The reattachment of adult ticks collected in the field was successful on only one of five attempts, and the subinoculation of blood from suspected heartwater carriers was unsuccessful. Seven of the isolates were derived from A variegatum ticks, four from A gemma, one from A lepidum and one from a mixed pool of the last two species. This is the first report of the isolation of C ruminantium from A gemma ticks, and the first report of its transtadial transmission from nymphal to adult A gemma.Item Kenya Agricultural Research Institute National Veterinary Research Centre Annual Scientific Seminar Proceedings 1 -2nd December 1992(Kenya Agricultural Research Institute, 1992) Kenya Agricultural Research Institiute; Kariuki, D.P.The National Veterinary Research Centre at Muguga is one of the 15 national centres designated by KARl under the Kenya National Research Project (NARP) to carry out research in agriculture, animal production and animal health under the following KARl S mandates:-Item Proceedings of the Scientific Conference held at the National Veterinary Research Centre, Muguga, 6th - 8th December, 1995(Kenya Agricultural Research Institute, 1995) Kenya Agricultural Research Institute, National Veterinary Research Centre Muguga; The KARI/ODA Livestock Projects; Kenya Trypanosomiasis Research Institute; Kariuki, D.P.; Wanyangu, S.W.; Mbogo, S.K.; Kenya Agricultural Research InstituteSince KARI begun this annual event in 1992, there has been tremendous improvement on what is being presented. The purpose is to tell on how scientists spent 12 months at the Centre as a Scientist. This year, the scientific conference included Scientists from Animal Production, CRISP and from Kenya Trypanosomiasis Research Institute. This is an indication that the Conference is becoming an established annual activity at this Centre In future we shall invite more institutes to participate. For research results to be of any use, they must be communicated to the end user - extension service and farmers. As a result of our training each individual at this Centre is becoming a specialist. This is very important for the development of each individual scientist. However, the Centre, through its training programme does not wish to produce a class of specialists or experts who work in isolation We are all working for farmers who have expertise and certain traditional approaches. This calls for collaboration with farmers (on-farm-research) and other scientists at the Centre and elsewhere so that at the end of day the Centre can produce an integrated package that the farmers can use to improve on what they know. Our research is not about problems but to generate technologies solve farmers problems. The Conference is organized around a number of themes There are 27 papers to be given ranging from epidemiology and socio-economics, animal production, tick-borne diseases, trypanosomiasis, helminthiasis and virology and rapporteurs have been appointed to summarize the status of knowledge and anticipated discussions in each area. They should summarize the gist of presentations and note significant points arising in discussions and particularly any gaps in knowledge or recommendation for further work.Item A recent outbreak of rinderpest in East Africa(1987) Kariuki, D.P.; Wafula, J.S.Rinderpest was brought under control in Kenya in 1976 but in April 1986 an outbreak of the disease occurred in cattle in Western Kenya, five kilometres from the Kenya-Uganda border. This was the first confirmed field outbreak of the disease in Kenya after a lull of over 10 years. Clinical disease was confined to unvaccinated zebu calves aged six to eight months from which rinderpest virus was isolated. High titres of antibodies to rinderpest virus were demonstrated in sera collected from sheep and goats that were grazing together with the affected cattle herds; there was, however, no evidence of clinical disease in these small ruminants and wildlife species in the affected area. The disease outbreak was rapidly stamped out by quarantine and vaccination.Item Responses to a vaccine trial for East Coast fever in two cattle herds at the Kenyan coast(1991) Mutugi, J.J.; Ndungu, S.G.; Linyonyi, A.; Maritim, A.C.; Mining, S.K.; Ngumi, P.N.; Kariuki, D.P.A total of 373 cattle (271 Zebu-European crosses and 102 pedigree Jerseys) were immunized against East Coast fever on two farms in the Kilifi District of Coast Province, Kenya. The cross breeds and the Jersey cattle received I ml of either 10-01 or 10-' dilution of Thellena parva parva Marikebuni stock, respectively and simultaneous treatment with a long-acting formulation of oxytetracycline. Following immunization, 362 cattle (96.5%) showed Theileria parva antibodies; 346 cattle (92.7%) seroconverted without clinical reactions. The Jersey cattle developed a higher proportion of clinical East Coast fever reactors (14.7%) following the immunization than the cross breeds (0.6%). All the calves immunized (37) on both farms seroconverted to Theileria parva antigen without any theilerial clinical reactions. The development of a serological response to East Coast fever was independent of the route of stabilate inoculation and was unaffected by concurrent infections such as trypanosomiasis and foot and mouth disease. Following immunization, no discernable effects on milk production were recorded, except from cattle undergoing a clinical reaction, where a transient reduction in milk production was seen. Thirty months later, the immunized cattle are reported to have withstood the disease challenge presented to them naturally on the farms without any breakdown in immunity to East Coast fever.
