Detection of Mycoplasma hyorhinis and Mycoplasma hyosynoviae in oral fluids and correlation with pig lameness scores

In this newly released article from the MycoLab in the Veterinary Microbiology journal, Dr. David Pillman working with Dr. Maria Pieters shares his results regarding detection of two mycoplasma species and how this was correlated with lameness scores in nursery and finishing pigs.

Key points

  • M. hyorhinis was frequently detected in oral fluids in nursery and finisher herds
  • High detection of M. hyosynoviae in oral fluids was observed in finisher herds.
  • Proportion of lame pigs and M. hyosynoviae detection in oral fluids were correlated.

37 Midwestern nursery or finishing farms with lameness issues participated in the study. Ten oral fluid samples were collected per farm and each sampled pen was scored for lameness (0-4). Oral fluids were then tested by PCR for Mycoplasma hyosynoviae and M. hyorhinis.

373 samples were analyzed in the study and 26% were from nursery age pigs. All of the samples tested positive for Mycoplasma hyorhinis except for one herd in Iowa. The detection level for Mycoplasma hyosynoviae varied between states but was also dependent upon the pigs age with finishing pigs being more often tested positive than younger pigs.

No correlation between lameness scores and the level of detection of M.hyorhinis. However, a high proportion of pigs were scored as lame in pen with a lower Ct value for M. hyosynoviae. Additionally, older pigs were more likely to be lame compared to younger ones.

Relationship between the proportion of lame pigs in a pen and the age of the pigs. 

Read more about this study on the journal’s website.


This study was designed to detect Mycoplasma hyorhinis and M. hyosynoviae in oral fluids and determine their correlation with lameness scores in pigs. Thirty-seven nursery and/or finisher herds were included in this study. Oral fluids were collected by pen. Using species specific real-time PCR M. hyorhinis was detected in 97% of sampled herds, whereas 70% were positive for M. hyosynoviae. Lameness scores were determined for all pigs in each pen where oral fluids were collected. Lameness was identified in 3.9% of pigs across all sampled pens. No correlation was observed between lameness in pigs in a pen and detection of M. hyorhinis in oral fluid samples (p > 0.05), whereas a significant correlation was observed between M. hyosynoviae detection in oral fluids and lameness (p < 0.05). A negative correlation was observed between the proportion of lame pigs in the pen and Ct values for M. hyosynoviae in oral fluids (p < 0.05; r = −0.27). An age-related effect was observed with M. hyosynoviae detection in oral fluids, indicating an increased prevalence of the bacterium in finishers compared to nursery pigs. Under the conditions of this study, M. hyorhinis was frequently detected in oral fluids from nursery and finisher pigs regardless of the clinical presentation of lameness, whereas the detection of M. hyosynoviae varied depending on the age of sample pigs. Our results suggest that oral fluids may not be an informative diagnostic sample for M. hyorhinis associated lameness. However, the association of lameness and M. hyosynoviae detection in oral fluids warrants prospective population-based diagnostic studies.

Leave a Reply