Large study of Bovine tuberculosis reveals extensive disease diversity in Cameroon
Researchers at the University of Edinburgh have carried out largest study to date of the prevalence and spread of Bovine tuberculosis in Cameroon, West Africa.
Cameroon is often called ‘Africa in miniature’ due to its geographical and cultural diversity. It now can also claim the highest M. bovis genetic diversity on the continent so far reported.
Bovine tuberculosis is an infectious disease in cattle and is caused by Mycobacterium bovis, which is endemic in Cameroon.
Livestock keepers, abattoir workers and consumers are unknowingly at risk of transmission through contact with infected animals and consumption of infected products. Given the high costs of existing control tools, most countries in Africa do not have very robust strategies for controlling the disease, and preventing zoonotic infection.
Dr Adrian Muwonge & Prof. Mark Bronsvoort from The Roslin Institute, and colleagues from the UK, Cameroon, Nigeria and Chad, conducted the largest molecular epidemiological study of bovine tuberculosis in a sub-Saharan African country to understand the incidence and diversity of the disease throughout Cameroon.
The team examined 2346 cattle after slaughter at abattoirs in four different cities across Cameroon, and collected 499 samples from 380 cattle, with and without bovine tuberculosis-like lesions. The scientists then analysed these samples to understand how, and to what extent, the pathogen was transmitted.
Considerable genetic diversity of M. bovis in Cameroon
The results showed that Bovine tuberculosis in Cameroon is highly genetically diverse and that this diversity is region specific. In the central Adamawa region, the disease is characterised by limited evidence of transmission but high prevalence of unique genotypes.
This is likely a product of constant additions from the seasonal active livestock movements. On the other hand the North West region is characterised by high reates of transmission and a local endemic expansion of genotypes.
Impact on human tuberculosis
There is an obvious need to control Bovine tuberculosis in Cameroon (e.g. disease-free zones and restricting animal movement) that can be aligned with the World Health Organization’s “END-TB” strategy aims of eliminating human tuberculosis as a public health challenge by 2035.
This new study provides much needed insight into cattle movements and disease spread, that can be used to inform ongoing development of control strategies.
N. F. Egbe, A. Muwonge, L. Ndip, R. F. Kelly, M. Sander, V. Tanya, V. Ngu Ngwa, I. G. Handel, A. Novak, R. Ngandalo, S. Mazeri, K. L. Morgan, A. Asuquo & B. M. de C. Bronsvoort. Molecular epidemiology of Mycobacterium bovis in Cameroon. Scientific Reports 7, 4652 (2017). doi:10.1038/s41598-017-04230-6