Evaluation of the feasibility of Mycoplasma hyopneumoniae detection in processing fluids

This report is the February edition of the Swine Disease Eradication Center (SDEC) research update. Not sure what the SDEC is? Check out this quick read about our research group collaborating with industry partners to solve problems faced by the swine industry.

Dr. Vilalta collaborated with Minnesota-based producers, the Veterinary Diagnostic Laboratory and the MycoLab to investigate processing fluids as a sample type for the detection of Mycoplasma hyopneumoniae.


The use of processing fluids (PF) to detect and monitor PRRSv and other pathogens is increasing among producers and veterinarians.

Preliminary data from our research team identified Mycoplasma hyopneumoniae in PF at the litter level, using a species-specific real-time PCR, in a M. hyopneumoniae endemically infected farm.


  • To investigate the detection of M. hyopneumoniae in non-respiratory tissues and fluids collected from suckling pigs at processing age.
  • To develop an in situ hybridization (ISH) assay to further identify M. hyopneumoniae in non-respiratory tissues.


Mycoplasma hyopneumoniae detection in non-respiratory tissues or fluids

All dams tested negative for M. hyopneumoniae by RT-PCR in blood, serum, colostrum, placenta, and vaginal swabs.

Fifty percent of dams were seropositive by Oxoid™ Mycoplasma hyopneumoniae ELISA.

All blood samples from stillborn and piglets resulted negative to M. hyopneumoniae by RT- PCR.

Mycoplasma hyopneumoniae was detected in 2/54 individual fluid samples (tails and testicles). M. hyopneumoniae was detected (Ct<40) over the 10-week period by RT-PCR.

PF and their associated testicles were collected individually at the litter level. All PF were tested by M. hyopneumoniae by RT-PCR. Samples were fixed in formalin to perform ISH on positive samples.

Development of an In situ hybridization assay

The ISH-RNA technique established the distribution of M. hyopneumoniae in affected tissues in association with histological lesions, characterized by lymphoplasmocytic peribronchiolitis and/or hyperplasia of the bronchoassociated lymphoid tissues.

In M. hyopneumoniae positive lungs, hybridization signals were observed in the apical membrane of the respiratory epithelium of bronchi and bronchioles.

Positive signals were also observed in inflammatory cells and degenerative epithelial cells within the bronchial and bronchiolar lumen.

The ISH-RNA technique provided molecular detection of M. hyopneumoniae cells expressing mRNA of proteins and elucidated the localization patterns by visualization in tissue.

The full report with details on the material and methods is available on our website.

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