The Paratuberculosis Newsletter - Online An Official Publication of the INTERNATIONAL ASSOCIATION for PARATUBERCULOSIS and Other Intestinal Mycobacterioses

The aim of this study was to use PARACHEK Johne's Absorbed EIA-CSL, gamma interferon test IFN BOVIGAM-CSL , Mycobacterial Growth Indicator Tube MGIT, BACTEC 960 BECTON-DICKINSON, PCR with IS900 probe, to diagnose paratuberculosis in sheep from the Argentine North East (ANE) and compare the results with those of the comparative skin testing using bovine and avian PPD (B-PPD and A-PPD), agar gel immunodiffusion (AGID), Ziehl-Neelsen stain, and culturing using Löwenstein-Jensen and Herrold’s (with/without mycobactin). Plasma, serum and faeces were collected from 66 Romney Marsh and Corriedale cross-bred sheep from three farms from Corrientes, Argentina Results: Skin tests with B-PPD versus PARACHEK -CSL ) had a specificity of 89%, APPD versus PARACHEK-CSL had a specificity of 88% , Comparative B-PPD and A-PPD skin test versus IFN BOVIGAM-CSL had a specificity of 98% and 88% respectively. The former versus culture had a specificity of 83%, IFN (BOVIGAM–CSL versus culture : 100% and 94% respectively , PARACHEK-CSL versus culture had a specificity of 88% and a sensitivity of 33%. All AGID tests were negative. Nine mycobacterial isolates were obtained from fecal cultures: 3 from Herrold’s with mycobactin, 2 from Herrold’s without mycobactin and 4 from MGIT-BACTEC 960, plus mycobactin. IS900 was shown by PCR to be present in 6 of the isolates. Conclusion : The joint use of tests will tend to clarify the infection status of animals and may result in lower costs and improved testing efficiency. Future research will be necessary to further define the sensitivity of the tests and determine how they can be optimally used as part of a disease control programme. INTRODUCTION Paratuberculosis (Johne’s disease) is a chronic granulomatous enteropathy of the ruminants, caused by Mycobacterium avium subsp. paratuberculosis. The infection is commonly transmitted by the fecal-oral route through contaminated pastures, water or milk. Intra-uterine infections have also been recorded (Whittington et to the, 2000). In Argentina it has been diagnosed in cattle, sheep, goats, deer, alpacas and llamas (Bernardelli et al., 1981/7/99; López et al.,1990; Moreira et al.,1993/9; Cicuta et al.,1995) and elsewhere also in rabbits, bison, rhinoceros, other herbivores, and primates (Meylan et al. ,1995; Cousins et al., 2000; Whittington et al., 2000). Crohn’s disease in humans has similar histopathology, bacteriology and clinical symptoms to paratuberculosis in domestic animals (Engstrand’s, 1995; Whittington et al., 2000). Paratuberculosis is a significant economic problem causing a 6 to 25% reduction in