1. Academic Validation
  2. Rapid and simple colorimetric loop-mediated isothermal amplification (LAMP) assay for the detection of Bovine alphaherpesvirus 1

Rapid and simple colorimetric loop-mediated isothermal amplification (LAMP) assay for the detection of Bovine alphaherpesvirus 1

  • J Virol Methods. 2021 Mar;289:114041. doi: 10.1016/j.jviromet.2020.114041.
Deborah Peltzer 1 Kurt Tobler 2 Cornel Fraefel 2 Madeleine Maley 3 Claudia Bachofen 2
Affiliations

Affiliations

  • 1 Institute of Virology, Vetsuisse Faculty, University of Zurich, 8057, Zurich, Switzerland. Electronic address: deborah.peltzer@bluewin.ch.
  • 2 Institute of Virology, Vetsuisse Faculty, University of Zurich, 8057, Zurich, Switzerland.
  • 3 Moredun Research Institute, Pentlands Science Park, Penicuik, Midlothian, EH26 0PZ, UK.
Abstract

As the causative agent of Infectious Bovine Rhinotracheitis (IBR) and Infectious Pustular Vulvovaginitis/Balanoposthitis (IPV/IPB), Bovine alphaherpesvirus 1 (BoHV-1) is responsible for high economic losses in the cattle industry worldwide. This study aimed to establish a fast, colorimetric loop-mediated isothermal amplification (LAMP) assay for the detection of viral DNA. Phenol red is used as pH-sensitive readout, relying on a distinct color change from pink to yellow in case of a positive reaction. LAMP reactions with different primers were compared and a newly designed set targeting the gene encoding the tegument protein V67 provided best results, enabling readout within 8-30 min. LAMP showed less cross-reactions with other ruminant alphaherpesviruses than qPCR but was 10-fold less sensitive. However, LAMP still detected down to 14 copies. The test performance was evaluated using 26 well-characterized nasal swabs from cattle with respiratory disease. All samples were correctly identified when using column-extracted DNA. Using a simple DNA precipitation method, only two weak-positive samples turned indeterminate. Combining this DNA precipitation with a makeshift water bath heated by a gastronomic immersion heater allowed successful application of the colorimetric LAMP assay under resource-limited conditions. This technique can therefore help in managing IBR/IPV outbreaks where sophisticated laboratory equipment is unavailable.

Keywords

Bovine alphaherpesvirus 1; Colorimetric LAMP; Infectious bovine rhinotracheitis; Isothermal amplification; Rapid detection; Resource-Limited application.

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