PCR clamping for selectively sequencing wild-type PRRSV in vaccinated herds

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are sharing a report by Harmon et al. from Iowa State University regarding PCR clamping. This project was funded by AAVLD Thermo Fisher Innovation Grant in Veterinary Diagnostic Medicine and ISU-VDL.

Key points

  • Conventional ORF5 sequencing may not differentiate between wild-type or vaccine-like.
  • Blocking the amplification of vaccine-like sequences it is possible to increase the likelihood of wild-type amplification.
  • Clamping allows the amplification of the wild-type with mixtures containing as little as 10% of a mixture with the vaccine-like.
Continue reading “PCR clamping for selectively sequencing wild-type PRRSV in vaccinated herds”

Sample types and diagnostic methods for early detection of Mycoplasma hyopneumoniae

In lieu of the Science Page today, we are bringing you our most popular articles on the blog this past year: a publication by Dr. Maria Pieters, head of the MycoLab called 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.

Link to the full-article