First report of the use of mucosal swabs of the palatine tonsillar crypt for detection ofMycoplasma bovisin naturally infected calves

Aims:To compare detection by real-time PCR of DNA fromMycoplasma bovison mucosal swabs taken from the palatine tonsillar crypt and the mainstem bronchi of clinically asymptomatic calves after slaughter. Methods:We compared the sensitivity of mucosal swabs taken from two sites: the palatine tonsillar crypt and the mainstem bronchi. Paired samples were taken post-mortem at slaughter from 55 clinically well calves from an infected herd and were tested by real-time PCR for the presence ofM. bovis-specific DNA. Results:Mycoplasma bovisDNA was detected in 51 palatine tonsillar crypt swabs (92.7 (95% CI = 82.4-98.0)%) and seven mainstem bronchial swabs (12.7 (95% CI = 5.3-24.5)%). All seven calves with positive mainstem bronchial swabs also had positive palatine tonsillar crypt swabs. Conclusions:When compared to mucosal swabs of the mainstem bronchi, mucosal swabs of the palatine tonsillar crypt were seven times more sensitive for the post-mortem detection ofM. bovisDNA. The viability of detectedM. boviswas not assessed, because any cattle carrying viable or non-viableM. bovisDNA were determined to be a potential risk to eradication. Palatine tonsillar crypt mucosa may be a useful anatomical site for real-time PCR detection ofM. bovisDNA in naturally infected calves. More work is needed to define the persistence and viability ofM. bovisat this anatomical site.