Bovine farcy: a clinico-pathological study of the disease and its aetiological agent

An extensive survey for bovine farcy covering 14,192 animals was conducted in the Sudan. The incidence of the disease was 31.9 per cent in Western Sudan which is regarded as an endemic area. Animals were examined clinically and at post-mortem. The lesions involved the prescapular, femoral, parotid, retropharyngeal, submaxillary, inguinal and mediastinal lymph nodes. Some animals had farcy lesions in the udder and some developed the pulmonary form of the disease. The disease is slow, but progressive in nature and was more prevalent among adult cattle than calves. Mycobacterium farcinogenes was found to be the cause of bovine farcy in the Sudan. The morphological and biochemical characteristics, and the mycolic acid content of the isolated strains were found to be identical to the reference strains of M. farcinogenes and were quite different from reference strains of Nocardia farcinica from which they were easily distinguished by the presence of alpha-mycolate, alpha'-mycolate and epoxymycolate in M. farcinogenes. Hydrolysis of mycolic acids with tetrabutylammonium hydroxide and the precipitation with toluene and acetonitrile gave good results comparable with acid methonalysis and alkaline hydrolysis. Precipitin lines were detected in the sera of some farcy-infected cattle. Histopathological examination of farcy lesions revealed a severe granulomatous reaction characterized by lymphocyte, macrophage, epithelioid and giant cell infiltration as well as marked fibrous proliferation. These changes were indicative of a progressive disease of the delayed tuberculin hypersensitivity type.