Detection of Mycoplasma sp using next-generation DNA sequencing is common on nasal swabs from both healthy and unhealthy pet rabbits (Oryctolagus cuniculus).

Objective: Upper respiratory infections are a frequent problem in pet rabbits and rodents, and Mycoplasma pulmonis is 1 of the most common causes of respiratory infections in pet rats. M pulmonis was detected in 1967 in laboratory rabbits via culture of the nares and oropharynx, but overall, Mycoplasma is not commonly identified in the upper airway of rabbits. The objective of this study was to compare the prevalence of Mycoplasma sp detection via next-generation DNA sequencing on nasal swabs obtained from healthy and unhealthy rabbits.

Methods: The results of nasal swabs from both healthy and unhealthy rabbits submitted for next-generation DNA sequencing from January 2022 to February 2023 were reviewed. Data gathered included signalment, whether or not Mycoplasma sp was detected, and the cell count and relative predominance of Mycoplasma sp compared to other organisms.

Results: 91 rabbits met the inclusion criteria, of which 49 were healthy and 42 were unhealthy. Overall, 52 of 91 (57.1%) rabbits were positive and 39 of 91 (42.8%) were negative for Mycoplasma sp. Mycoplasma positivity was significantly (P < .001) more common in healthy rabbits (37/49 [75.5%]) compared to unhealthy rabbits (15/42 [35.7%]).

Clinical relevance: The fact that Mycoplasma positivity was common in both groups of rabbits, and particularly common in rabbits without upper respiratory signs, suggests that Mycoplasma may be normal nasal flora in rabbits. Further research is needed to determine whether Mycoplasma could function as an opportunistic pathogen in rabbits.