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Pathogenicity of Mycoplasma volis in mice and rats
K D Evans-Davis1, D L Dillehay, D N Wargo
1Division of Animal Resources, Emory University School of Medicine, Atlanta, Georgia, USA.
Abstract:
A new species of Mycoplasma, M. volis, was isolated from the respiratory tract of clinically normal field-trapped prairie voles (Microtus ochrogaster) 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 severe combined immunodeficient [SCID] mice) were intranasally inoculated with 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 signs of disease; however, one experimental SCID mouse was euthanized 5 days after inoculation because of a severe circling disorder. Lung lesions in experimental SD rats ranged from mild to severe bronchial-associated lymphoid tissue (BALT) hyperplasia. Lung lesions in BALB/c and SCID mice ranged from no lesions to mild pneumonia. We were able to isolate M. volis from some control mice, none of which had lung lesions. All mice were seronegative for Sendai virus, mouse hepatitis virus, and M. pulmonis. All immunocompetent experimental animals (BALB/c mice and Sprague Dawley rats) were seropositive for M. volis. All immunocompetent control animals and SCID mice were seronegative for M. volis. Our data suggest that M. volis is capable of causing microscopic lesions and seroconversion in rats and mice, and therefore these rodents should not be housed in close proximity to voles.
Insights
A new Mycoplasma species, M. volis, isolated from prairie voles can cause microscopic lung lesions and seroconversion in rats and mice. These findings indicate potential transmission risks when housing these rodents together.
Area of Science:
- Veterinary Microbiology
- Rodent Pathology
Background:
- A novel Mycoplasma species, M. volis, was identified in clinically normal prairie voles (Microtus ochrogaster).
- The potential pathogenicity of M. volis in other rodent species was unknown.
Purpose of the Study:
- To assess the pathogenic potential of M. volis in Sprague Dawley rats, BALB/c mice, and severe combined immunodeficient (SCID) mice.
- To evaluate the risk of M. volis transmission between voles and other common laboratory rodents.
Main Methods:
- Rodents were intranasally inoculated with M. volis (2 x 10(8) CCU).
- Animals were observed for clinical signs and lung lesions over 4-6 weeks.
- Serological testing was performed for M. volis and common rodent pathogens.
Main Results:
- No clinical signs of disease were observed, except for one SCID mouse with a circling disorder.
- Microscopic lung lesions, including bronchial-associated lymphoid tissue (BALT) hyperplasia and mild pneumonia, were noted in rats and mice.
- M. volis was re-isolated from some control mice without lesions.
- Seroconversion to M. volis occurred in immunocompetent experimental rats and mice.
Conclusions:
- M. volis can induce subclinical infections, microscopic lesions, and seroconversion in rats and mice.
- Close housing of prairie voles with rats and mice should be avoided to prevent potential Mycoplasma transmission.