Epidemiology of Bovine Tuberculosis in Cameroon

The project is a Wellcome Trust funded study of the epidemiology and phylodynamics of bovine tuberculosis in cattle and their herders in Cameroon. The project is a collaboration between the Roslin Institute, the University of Buea (Cameroon), the Swiss TPH, IRAD (Cameroon) and Ministry of Health Cameroon.

Bovine tuberculosis in an important infectious disease of livestock (particularly cattle), which, has the potential to infect humans exposed to infected milk or meat. This project will collect new data from a random sample of cattle across the three main cattle rearing regions of Cameroon (The North West, the Adamawa and the Extreme North) to identify management (herd-level) and animal-level factors that affect the spatial patterns of disease and which may identify mechanisms to improve control. Furthermore, screening of animals at slaughter will allow the identification of infected animals from which bacteria will be cultured and their specific genetic strain identified. Using the variation in these strains and linking it to management factors and animal movements, we will be able to understand the dynamic spread of the disease and potential critical control points in the production chain that would facilitate disease control. A crucial part of achieving this is having accurate and easy to use screening tests. The diagnostic test data will be analyzed using advanced statistical techniques which consider test interactions and the influence of co-infection to give maximum utility to future application.

The main objectives of the study are to estimate the prevalence of infected cattle using a population based sample of herds using the gamma interferon test; estimate the performance of the test compared to skin testing and the impact of co-infections such as fasciola or BVD; identify the spoligotypes in the cattle population through both milk and abattoir sampling and testing and also to identify strains in the associated human populations.

The field work for the project is now complete and we are in the data analysis phase. Over 2000 cattle were sampled from abattoirs across Cameroon. We have isolated a large number of Mycobacteria from cattle. These are mainly M. bovis but we have also isolated a number of NTMs and also a human M. tuberculosis. Currently we have 3 spoligotypes from the North West Region but further analysis of the remaining isolates from the other 3 abattoirs is underway.