Browsing by Author "Gachohi, J.M."
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Item Estimating seroprevalence and variation to four tick-borne infections and determination of associated risk factors in cattle under traditional mixed farming system in Mbeere District, Kenya(2010) Gachohi, J.M.; Ngumi, P.N.; Kitala, P.M.; Skilton, R.A,; International Livestock Research Institute (ILRI), Old Naivasha Rd, Kabete, P.O. Box 30709-00100, Nairobi, Kenya, Kenya Agricultural Research Institute, Trypanosomiasis Research Center, Muguga, P.O. Box 362-00902, Kikuyu, Kenya, Department of Public Health, Pharmacology and Toxicology, College of Agriculture and Veterinary Sciences, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya, Biosciences Eastern and Central Africa (BecA) – ILRI Hub, Old Naivasha Rd, Kabete, P.O. Box 30709-00100, Nairobi, KenyaA cross-sectional study of serum antibody responses of cattle to tick-borne disease (TBO) parasites (Theileria parva. Theileria mutans. Anaplasma marginale and Babesia bigeminal was conducted on traditional smallholder mixed farms in Mbeere District in Kenya. The objective was to estimate the infections' seroprevalence and variation and identify associated risk factors. A total of 440 cattle in 80 farms, selected by stratified random sampling from the four divisions in the district, were surveyed. Information on animal and on each farm 's management practices, particularly on tick control practices, was obtained by personal interview using a standardized questionnaire. Prevalences of serum antibodies were determined using the enzyme-linked immunosorbent assay (ELISA) technique. The relationship between TBOs seroprevalence and the risk factors was assessed by multivariable analysis using standard logistic regression models and mixed models using the farm as a random effect. Overall estimation of seroprevalences and their 95% confidence limits were: T. parva (19% [14%. 25%)). T. mutans (25% [20%. 29%)). A. marginale (58% [52%. 64%)) and B. bigemina (19% [15%. 23%)). Analysis in presence of extra-binomial variation under Analysis Of Variance (ANOVA) yielded relatively larger intra-farm correlation coefficient (ICC) (0.3) and variance-inflation factor (VIF) (2.35) values for T. parva than for the other parasites [range. 0.05-0.07 (for ICC) and 1.02-1.32 (for VIF)]. Both farm- and area-level variables had variably significant and large effects on all infections, but these were more pronounced on T. parva seroprevalence. Inclusion offarm random effect resulted in substantially higher estimate of farm variance component for T. parva infection (1.73) compared to other infections [range. 0.29-0.56]. comparable ICC values with those under ANOVA analysis [range. 0.08-0.35] and a substantially better fit than the standard multivariable logistic regressions. The above results serve as possible indicators of existence of endemic instability for the studied TBO infections in the district. A probable differential ecological and climatic variability in vector suitability habitats, particularly for T. parva vector, was likely in Mbeere District and this was suggested to influence farm tick control management across the area. Implications of the design-based sampling and analyses on the above results are also discussed.Item Factors influencing the prevalence of trypanosomosis in Orma Boran (trypanotolerant) and Teso zebu (trypanosusceptible) cattle crosses in Teso District, western Kenya(2009) Gachohi, J.M.; Bett, B.; Murilla, G.A.; Kenya Trypanosomiasis Research Institute; Kenya Agricultural Research Institute, Trypanosomiasis Research Centre (KARI-TRC), International Research InstituteThe objective of this study was to determine factors associated with occurrence of trypanosomosis in the first generation (F1) crossbreds between trypanotolerant Orma Boran and trypanosusceptible Teso zebu cattle in a trypanosomosis endemic area in Teso District, western Kenya. The offspring were screened for trypanosomosis and other haemoparasites using parasitological methods. Packed cell volume (PCV), body weights and tsetse density (FTD) were also determined. Factors considered in the analysis included sex, age, body weight and season of the year. Generalized linear mixed models (GLMM) were used for multivariable analysis to account for clustering of observations at the animal level and estimate outcome variance parameters.Item Factors influencing the prevalence of trypanosomosis in Orma Boran (trypanotolerant) and Teso zebu (trypanosusceptible) cattle crosses in Teso District, western Kenya(2009) Gachohi, J.M.; Bett, B.; Murilla, G.A.; Kenya Agricultural Research Institute, Trypanosomiasis Research Center (KARI-TRC), International Livestock Research Institute (ILRI)The objective of this study was to determine factors associated with occurrence of try panosomos is in the first generation (F 1) crossbreds between trypanotolerant Orma Boran and trypanosusceptible Teso zebu cattle in a trypanosomosis endemic area in Teso District, western Kenya. The offspring were screened for trypanosomosis and other haemoparasites using parasitological methods. Packed cell volume (PCY), body weights and tsetse density (FTD) were also determined. Factors considered in the analysis included sex, age, body weight and season of the year. Generalized linear mixed models (GLMM) were used for multivariable analysis to account for clustering of observations at the animal level and estimate outcome variance parameters.Item Theileria Parva Infection Seroprevalence and Associated Risk Factors in Cattle in Machakos County, Kenya(Springer Nature, 2014) Wesonga, F.D.; Gachohi, J.M.; Kitala, P.M.; Gathuma, J.M.; Njenga, M.J.; Kenya Agricultural Research Institute (KARI); International Livestock Research Institute (ILRI); University of NairobiThe principle objective of this study was to estimate the infection seroprevalence and identify risk factors associated with Theileria parva infection in cattle on smallholder farms in Machakos County, Kenya. A total of 127 farms were selected by a proportional allocation approach based on the number of farms in four divisions in the county previously selected by stratified random sampling method. Subsequently, a total sample of 421 individual animals was randomly selected from the farms. Information on animal and relevant individual farm management practices was gathered using a standardized questionnaire. Prevalence of serum antibodies was determined using the enzyme-linked immunosorbent assay (ELISA). Multivariable logistic models incorporating random effects at the farm level evaluated the association between the presence of T. parva antibodies and the identified risk variables. The overall estimation of T. parva antibodies in the county was 40.9 % (95 % confidence interval of 36.1, 45.7 %). Seroprevalence to T. parva was significantly associated with animal age, vector tick infestation in the animal, tick control frequency, and administrative division. Further analyses suggested a confounding relationship between administrative division and both breed and grazing system and the T. parva seropositivity. Random effects model yielded intra-farm correlation coefficient (ICC) of 0.18. The inclusion of farm random effect provided a substantially better fit than the standard logistic regression (P = 0.032). The results demonstrate substantial variability in the T. parva infection prevalence within all categories of the cattle population of Machakos County of Kenya, where East Coast fever is endemic.
