Comparison of Diagnostic Detection Methods for Mycobacterium avium subsp. paratuberculosis in North American Bison

Abstract

Abstract. Tissues and fecal material were collected from 14 North American bison (Bison bison) that were suspected of having Johne's disease and analyzed for the presence of Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis). Sections of ileum, ileal-cecal lymph node, and three sequential sections of jejunum with their associated mesenteric lymph nodes were taken from each animal. Fecal culture indicated that 5 of 14 (35.7%) animals were infected, whereas cultures from tissues detected 12 of 14 (85.7%) animals as infected and 59 of 111 (53.2%) of the tissues as positive for M. paratuberculosis. Polymerase chain reaction analysis identified infection in 14 of 14 (100%) animals and in 91 of 112 (81.2%) tissues. In addition, tissues were processed for Ziehl-Neelsen acid-fast staining, auramine O/acridine orange fluorescent staining, and immunohistochemical staining. Ziehl-Neelsen and auramine O staining identified 7 of 14 (50%) and 5 of 14 (35.7%) animals as infected and 24 of 112 (21.4%) and 28 of 112 (25%) tissues as positive, respectively. Immunohistochemical analyses of bison tissues, using antisera collected from rabbits immunized with four different preparations of M. paratuberculosis, identified a greater percentage of infected animals (ranging from 57 to 93%) and positive tissues (ranging from 28 to 46%). Collectively, these data indicate that DNA-based detection of M. paratuberculosis was more sensitive than bacterial culture or staining, identified infection in all the bison, and detected the greatest number of positive tissues within each animal.

Development and validation of a triplex real-time PCR for rapid detection and specific identification of M. avium sub sp. paratuberculosis in faecal samples

“…Although PCR-based screening methods performed on (pooled) faecal samples are nowadays offered in some countries, a combination of direct examination of ZN-stained smears, serological methods and culture is still mainly used routinely by veterinary diagnostic laboratories for identifying infected farms (Harris and Barletta, 2001). The rationale for using DNA-based Mapspecific assays on faecal material stems from the expected higher sensitivity and faster performance compared to the culture (Bogli-Stuber et al, 2005;Fang et al, 2002;Huntley et al, 2005;Tasara et al, 2005;Tripathi et al, 2006). Using this experimental Map infection model allowed us to monitor Map excretion over almost 3 years time in the same Map exposed animals and to compare the performance of conventional methods with our DNA-based detection assay on serial faecal samples.…”

Detection of Mycobacterium avium subsp. paratuberculosis by several diagnostics techniques in clinical suspected sheep

“…This means that a significant amount of time is needed before a diagnosis can be made (Huntley et al 2005). In addition, the isolation of the bacteria is also difficult due to intermittent shedding and a low number of bacilli in faeces and tissues respectively (Pavlík et al, 2000, Reddacliff et al, 2003.…”

Contrasting Results of Culture-Dependent and Molecular Analyses of Mycobacterium avium subsp. paratuberculosis from Wood Bison

“…Only one clinical case of JD has been observed in this herd; this occurred in 2006 (Alberta Agriculture, Food and Rural Development, unpublished data). Johne's disease has been described in commercial plains bison (30,31), which show lesions and clinical disease similar to what is typical in cattle. However, given that captive plains bison have different habitats, population densities, and genetic backgrounds from those of wood bison and may be infected with different M. avium subsp.…”