Diagnostic approaches to avian tuberculosis

Avian tuberculosis is a chronic infectious disease caused by M. avium including four subspecies Mycobacterium avium subspecies avium ; M. avium hominissuis ; M. avium paratuberculosis ; M. avium silvaticum . This disease is characterised by the formation of granulomatous lesions in viscera, a progressive weight loss and death. It can be transmitted to healthy birds in the flock, and occasionally to human beings. It is important to diagnose avian tuberculosis in order to prevent the spread of infection and epidemiology. This paper reviews the available techniques for the diagnosis of avian tuberculosis along with their pros and cons. The main problem in diagnosis is poor availability of samples due to infrequent shedding in faeces, pattern and colour of feathers, wattle and comb and lack of specific signs and symptoms. Any single technique is not effective in diagnosing the disease due to the lack of required sensitivity and specificity. Application of two or more techniques is not a feasible option in developing countries due to financial constraints. In the short term, more research is needed to develop multidisciplinary approaches which can help fully understand the aetiology and epidemiology of disease.