Estimating the prevalence of bovine tuberculosis (BTB) using indirect elisa test in selected counties of Kenya

Abstract

Bovine tuberculosis (BTB) is an important zoonotic disease whose eradication has proved problematic due to the challenges in effective screening and diagnosis. A study to determine the presence and prevalence of bovine tuberculosis antibodies in seven Counties of Kenya was carried out between August and December 2013. The study used sera that were collected from seven counties in Kenya between 2011 and August 2013 and stored at the Central Veterinary Laboratories (CVL), Kabete Nairobi. The samples were sorted and only those with well recorded identity selected for testing. The study utilized a newly developed antibody ELISA Kit. A total of 644 bovine serum samples were tested using MPB70 and MPB83 recombinant proteins as capture antigens to detect the presence of BTB antibodies. The prevalence was determined as a proportion of the positive samples out of total samples tested and the data were exported to SPSS 16.0 version for analysis. Descriptive statistical analysis were then done to determine the proportions and distribution across the counties. Graphs and charts were drawn using Microsoft excel. The study showed a prevalence of 3.57% (23/644) with Wajir County having the highest prevalence of 4.7% (4/85) and Kilifi county having the least at 0% (0/64). On Chi-square and Fishers exact test there was no significant association between BTB infection and the age of animals, categorized as young (below 3 years) and old (above 3 years of age) at (P= 0.05507). Breed and sex indicated no significant association at (P=0.4111) and (P=0.2354) respectively. Kappa statistics for ELISA test and Tuberculin skin test (TST) showed a strong agreement for the two M. bovis tests at K= 0.65. This study has documented the prevalence of BTB in cattle for the first time in Kenya utilizing a more specific antibody ELISA. This method of diagnosis presents a quicker and a cheaper way that can be complementary or an alternative to the screening of BTB in live animals. This study also concludes that BTB is present in Kenyan cattle populations without a significant relation to age sex and breed of animals. On the basis of these findings, this study recommends a survey of all Counties and wildlife reserves to map out prevalence status in the whole country. It also recommends specific policy formulation on the control of BTB in Kenya.