The detection of Mycobacterium paratuberculosis in bovine faeces by isolation and the comparison of isolation with the examination of stained smears by light microscopy
The detection of Mycobacterium paratuberculosis organisms in bovine faeces by isolation was compared with that by the microscopical examination of Ziehl-Neelsen stained faecal smears for the presence of clumps of acid-fast M. parutuberculosis organisms. Faeces were obtained from cattle nakurally or experimentally infected with M. parutuberculosis as well as from uninfected cattle. Microscopical examination was an unreliable method for the detection of M. parutuberculosis organisms, since the organisms were only detected in 99 (=55.9%) of 177 culturally positive faecal samples. 1111 addition, clumps of acid-fast organisms indistinguishable from M. parutuberculosis were also observed iin three of 18 samples from cattle free from Johne`s disease and in 18 of 37 culturally negative samples from paratuberculous cattle. When M. paratuberculosis organisms were added to faeces from an uninfected cow, results showed that isolation attempts should be positive when 15 or more M. paratuberculosis organisms per gram of faeces are present.
Document Type: Research Article
Publication date: 1988-09-01