Molecular characterization of Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis) isolates classifies them into three groups: cattle or Type II, sheep or Type I, and intermediate or Type III. To avoid problems associated with characterization of extremely slow growth strains, PCR-based techniques that divide the M. a. paratuberculosis strains in two main groups (cattle or Type II, and sheep or Types I/III) can be performed. The objectives of this study were to characterize the M. a. paratuberculosis isolates identified by different PCR-based tests (IS1311-PCR and restriction endonuclease analysis, PCR test based on a DNA sequence difference, and a PCR aimed at three Type I-specific loci), and to determine the clinical and epidemiological implications of Types I/III M. a. paratuberculosis strains in livestock. One hundred and fifty-eight M. a. paratuberculosis strains from domestic ruminants were analyzed. One hundred and six M. a. paratuberculosis isolates (61 from goats and 45 from cattle) were classified as Type II strains; and 52 (29 from cows, 20 from goats, and three from sheep) were included in the Types I/III. The Types I/III M. a. paratuberculosis strains were associated to Spanish native breeds. The majority of these animals had not been in direct or indirect contact with sheep flocks infected with M. a. paratuberculosis. This fact should be taken into account when implementing paratuberculosis control programs.
Bibliographical noteFunding Information:
This work was funded by the European Commission (QLRT-2000-01420) and by the Spanish Ministry of Agriculture, Fisheries and Food (MAPA). We thank the collaboration of the Dirección General de Sanidad Agropecuaria, Consejería de Agricultura y Ganadería (Junta de Castilla y León), and the Dirección General de Agricultura, Consejería de Economía e Innovación Tecnológica (Comunidad de Madrid). We are grateful to P. Díez de Tejada, J.M. Fernández, and A. Santos for samples and excellent collaboration. We are grateful to Matthew Gilmour for careful revision of the manuscript.
- Mycobacterium avium subsp. paratuberculosis
- Type I
- Type II
- Type III