Susceptibility of the lemming (Dicrostonyx rubricatus) to Mycobacterium paratuberculosis.

The susceptibility of the lemming (Dicrostonyx rubricatus) to Mycobacterium paratuberculosis was studied. Twelve lemmings were exposed to cultural material of M paratuberculosis and were necropsied at 40- to 260-day intervals after exposure. Selected tissues were examined bacteriologically and histologically. Mycobacterium paratuberculosis was recovered from all exposed lemmings except the one necropsied 40 days after exposure. Pathologic changes typical of paratuberculosis were seen in a few lemmings. Clinical signs of disease were not seen. Rate of growth and general appearance of the exposed lemmings and the normal controls did not differ. The extent of infection in this species of lemming was similar to that seen in exposed hamsters.