Epidemiological study of paratuberculosis in wild rabbits in Scotland

Abstract

A survey of 22 farms confirmed the presence of paratuberculosis in wild rabbits in Scotland. Regional differences were apparent in the prevalence of the disease in rabbits, with a significantly higher incidence occurring in the Tayside region. Statistical analysis showed a significant relationship between a previous history or current problem of paratuberculosis in cattle and the presence of paratuberculosis in rabbits on the farms. Molecular genetic typing techniques could not discriminate between selected rabbit and cattle isolates from the same or different farms, suggesting that the same strain may infect and cause disease in both species and that interspecies transmission may occur. The possibility of interspecies transmission and the involvement of wildlife in the epidemiology of paratuberculosis have important implications for the control of the disease.

FIG. 1

Map of Scotland showing regions sampled in the survey.

FIG. 2

Long restriction fragments of M. avium subsp. paratuberculosis isolates from rabbits (R prefix) and cattle (F prefix) from farm A. Chromosomal DNA was digested with HindIII and subjected to PFGE as described in Materials and Methods. MW, PFGE molecular weight markers (Mid-Range II; New England Biolabs); values are indicated in kilobases.

FIG. 3

DNA fingerprinting of isolates from rabbits and cattle (DNA types C16 and C17).

FIG. 4

Composite photograph showing the six representative chemotypes of M. avium subsp. paratuberculosis isolates from rabbits and cattle on farms A and C, as determined by the MSPD-TLC method. Lanes: 1, hexane extract; 2, methylene chloride extract; 3, acetonitrile extract; 4, methanol extract; and 5, H₂O extract. Note the close similarity of groups III and IV.