Sample and diagnostic types for early detection of Mycoplasma hyopneumoniae

Summary:

Mycoplasma hyopneumoniae is the causative agent enzootic pneumonia, an economically significant disease in pigs. In this study published by Drs. Pieters and Rovira from the University of Minnesota, pigs experimentally inoculated with M.hyopneumoniae were sampled 0, 2, 5, 9, 14, 21, and 28 post-inoculation.

Different sample types were compared:

  • Nasal swabs
  • Laryngeal swabs
  • Tracheobronchal lavages
  • Oral fluids
  • Serum samples

Using different diagnostic tests:

  • PCR
  • ELISA IgG anti M.hyopneumoniae
  • ELISA Ig M anti M.hyopneumoniae
  • ELISA C-reactive protein

Laryngeal swab samples tested by PCR were highly sensitive for detection of Mycoplasma hyopneumoniae in live pigs.
Various commercial ELISA kits for detection of Mycoplasma hyopneumoniae antibodies showed similar sensitivity.
Oral fluids showed a low sensitivity for detection of Mycoplasma hyopneumoniae in experimentally infected pigs.

Pieters Mhyopneumoniae early detection test sample 2017

Abstract

Detection of Mycoplasma hyopneumoniae in live pigs during the early stages of infection is critical for timely implementation of control measures, but is technically challenging. This study compared the sensitivity of various sample types and diagnostic methods for detection of M. hyopneumoniae during the first 28 days after experimental exposure. Twenty-one 8-week old pigs were intra-tracheally inoculated on day 0 with M. hyopneumoniae strain 232. Two age matched pigs were mock inoculated and maintained as negative controls. On post-inoculation days 0, 2, 5, 9, 14, 21 and 28, nasal swabs, laryngeal swabs, tracheobronchial lavage fluid, and blood samples were obtained from each pig and oral fluid samples were obtained from each room in which pigs were housed. Serum samples were assayed by ELISA for IgM and IgG M. hyopneumoniae antibodies and C-reactive protein. All other samples were tested for M. hyopneumoniae DNA by species-specific real-time PCR. Serum antibodies (IgG) to M. hyopneumoniae were detected in challenge-inoculated pigs on days 21 and 28. M. hyopneumoniae DNA was detected in samples from experimentally inoculated pigs beginning at 5 days post-inoculation. Laryngeal swabs at all samplings beginning on day 5 showed the highest sensitivity for M. hyopneumoniae DNA Detection, while oral fluids showed the lowest sensitivity. Although laryngeal swabs are not considered the typical M. hyopneumoniae diagnostic sample, under the conditions of this study laryngeal swabs tested by PCR proved to be a practical and reliable diagnostic sample for M. hyopneumoniae detection in vivo during early-stage infection.

Link to the full-article

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s