PATHOGENICITY OF MYCOPLASMA-VOLIS IN MICE AND RATS

A new species of Mycoplasma, M. volis, was isolated front the respirat ory tract of clinically normal field-trapped prairie voles (Microtus o chrogaster) that were to be housed in close proximity to other rodents . To determine the pathogenic potential of the new mycoplasmal isolate , three groups of rodents (Sprague Dawley rats, BALB/c mice, and sever e combined immunodeficient [SCID] mice) were intranasally inoculated w ith 2 x 10(8) color-changing units (CCU) of M. volis and were observed for 4 to 6 weeks. Experimental animals did not manifest clinical sign s of disease; however, one experimental SCID mouse was euthanized 5 da ys after inoculation because of a severe circling disorder, Lung lesio ns in experimental SD rats ranged from mild to severe bronchial-associ ated lymphoid tissue (BALT) hyperplasia, Lung lesions in BALB/c and SC ID mice ranged from no lesions to mild pneumonia. We were able to isol ate M. volis from some control mice, none of which had lung lesions, A ll mice were seronegative for Sendai virus, mouse hepatitis virus, and M. pulmonis. All immunocompetent experimental animals (BALB/c mice an d Sprague Dawley rats) were seropositive for M. volis, All immunocompe tent control animals and SCID, mice were seronegative for M. volis. Ou r data suggest that M. volis is capable of causing microscopic lesions and seroconversion in rats and mice, and therefore these rodents shou ld not be housed in close proximity to voles.