A comparison between indirect ELISA and tuberculin skin test in the diagnosis of bovine tuberculosis in Kenya

Abstract

Bovine tuberculosis (BTB) is an important zoonotic disease which has remained persistent in many areas of the World. Control and eradication has proved problematic due to the challenges in effective screening and diagnosis. Limited information on the status of BTB in Kenya presents a need to investigate its occurrence in cattle population. The study was carried out using an indirect antibody Enzyme Linked Immunosorbent Assay (ELISA-IDEXX-USA) to assess the agreement with Comparative Intradermal Tuberculin Test (CITT) test results between August and December 2013 in Laikipia County. The study also determined the apparent prevalence of cattle BTB antibodies in Laikipia County. A total of 276 bovine serum samples were tested using MPB70 and MPB83 recombinant proteins as capture antigens in the ELISA kit. Data were recorded in Microsoft Excel and exported to SPSS 16.0 for analysis. Apparent prevalence was calculated as a proportion at 95% CI, Kappa statistics computed, and test of significance assessed by Chi-square and Fisher exact test.  The results showed an individual animal apparent prevalence of 3.9% (11/276) and a herd prevalence of 58.3% (7/12). There was no significant association between BTB infection and both animal level factors, breed and sex. Kappa agreement test between ELISA test and TST showed a good agreement at K= 0.65. This study reported the prevalence of BTB in cattle for the first time in Laikipia County Kenya using the IDEXX ELISA. The ELISA test was comparable to the tuberculin test which is used as the gold standard for screening TB on live animals. The two tests can be used alongside for series or parallel interpretation to achieve desirable diagnostic sensitivity and specificity in disease control programs.