Epidemiology, pathology, immunology and diagnosis of bovine farcy: a review

Bovine farcy (which is caused by Mycobacterium farcinogenes and Mycobacterium senegalense) is a chronic suppurative granulomatous inflammation of the skin and lymphatics of cattle and is seen mostly in sub-Saharan Africa. It is not yet certain whether Nocardia farcinica causes cutaneous nocardiosis (farcy) in animals that mimics bovine farcy. Epidemiological data have steadily reported finding bovine farcy in adult cattle of the transhumance pastoralist tribes of the Sahel and the Sudanian savannah zones. M. farcinogenes and or M. senegalense do not affect other domestic or non-domestic animals; it is not known whether these bacteria are zoonotic. The disease--once widespread in many regions--has disappeared from some countries historically known to have it. Reports of bovine farcy prevalence seem to be linked to the existence of survey initiatives by governments and diagnostic capabilities in each country. Farcy causes economic loss due to damaged hides and also is a public-health burden (because the lymphadenitis due to farcy resembles the lesions of bovine tuberculosis in carcasses and the meat is considered inappropriate for human consumption). The current literature is deficient in establishing definitely the prevalence, transmission patterns, and risk factors of bovine farcy. Ixodid ticks transmit other skin diseases (such as dermatophilosis) and might play a role in bovine farcy (given the similarity in the bio-physiology and geographic distribution of the disease). In addition, the tick-resistance of cattle breeds such as the N'Dama, Fulani or the Nilotic might explain their resistance to bovine farcy. Apart from the judicious use of conventional smear-and-culture methods, few diagnostic tests have been developed; the molecular and serological tests have not been evaluated for reproducibility and accuracy. This review points out aspects of bovine farcy that need further research and updates available data on the prevalence, distribution, risk factors, economic and public health implications, diagnosis, and control.