Bovine Tuberculosis in Cattle in the Highlands of Cameroon: Seroprevalence Estimates and Rates of Tuberculin Skin Test Reactors at Modified Cut-Offs

J Awah-Ndukum,P L Dickmu,A C Kudi,W N Agharih,G Bradley,G S Bah,H N Njakoi,S F Tebug

doi:10.1155/2012/798502

Abstract

The aim of this study was to obtain epidemiological estimates of bovine tuberculosis (TB) prevalence in cattle in the highlands of Cameroon using two population-based tuberculin skin test (TST) surveys in the years 2009 and 2010. However, prior to the TST survey in 2010, blood was collected from already chosen cattle for serological assay. Anti-bovine TB antibodies was detected in 37.17% of tested animals and bovine TB prevalence estimates were 3.59%–7.48%, 8.92%–13.25%, 11.77%–17.26% and 13.14%–18.35% for comparative TST at ≥4 mm, ≥3 mm and ≥2 mm cut-off points and single TST, respectively. The agreement between TST and lateral flow was generally higher in TST positive than in TST negative subjects. The K coefficients were 0.119, 0.234, 0.251 and 0.254 for comparative TST at ≥4 mm, ≥3 mm and ≥2 mm cut-off points and the single TST groups, respectively. Chi square statistics revealed that strong (P < 0.05; χ 2 > 48) associations existed between seroprevalence rates and TST reactors. The study suggested that using lateral flow assay and TST at severe interpretations could improve the perception of bovine TB in Cameroon. The importance of defining TST at modified cut-offs and disease status by post-mortem detection and mycobacterial culture of TB lesions in local environments cannot be overemphasised.

Highlights

Bovine tuberculosis (TB) is a zoonotic disease with severe public health significance but it is neglected in Cameroon
Of 807 tested cattle, antibovine TB Ab was detected in 37.17% while 11.77%, 8.92%, and 3.59% of them were single intradermal comparative cervical tuberculin (SICCT)-bovine tuberculin (BT) positive at ≥2 mm, ≥3 mm, and ≥4 mm cutoff points, respectively
Analysis of all antibovine TB Ab reactors (300) revealed that 25.33%, 21.33%, 9.67%, and 27% of them were positive at the SICCT-BT ≥ 2 mm, ≥3 mm, and ≥4 mm cutoff points and single intradermal tuberculin (SIT)-BT, respectively

Summary

Introduction

Bovine tuberculosis (TB) is a zoonotic disease with severe public health significance but it is neglected in Cameroon. The tuberculin skin tests (TSTs) are currently the best available techniques for international field diagnosis of bovine TB in live animals [1, 2] and it is based on delayed hypersensitivity reactions [3]. The single intradermal comparative cervical tuberculin (SICCT) test involving the intradermal injection of bovine tuberculin (BT) and avian tuberculin (AT) at separate sites in the skin of the neck gives more specific results than the single intradermal tuberculin (SIT) test which uses only BT [4, 5]. TST can effectively detect early stages of M. bovis infection in cattle and allows for rapid removal of infected animals, limited transmission, and fast eradication of bovine TB [6]. The OIE-recommended cutoff values were established mainly in developed countries for Bos taurus cattle, and different cutoff

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