Detection and quantitation of equid gammaherpesviruses (EHV-2, EHV-5) in nasal swabs using an accredited standardised quantitative PCR method
Résumé
Equid gammaherpesviruses-2 and -5 are involved in respiratory problems, with potential clinical man-ifestations such as nasal discharge, pharyngitis and swollen lymph nodes. These viruses are sometimesassociated with a poor-performance syndrome, which may result in a significant and negative economicimpact for the horse industry. The aim of the present study was to develop and validate quantitative PCRmethods for the detection and quantitation of EHV-2 and EHV-5 in equine respiratory fluids. Two dis-tinct tests were characterised: (a) for the qPCR alone and (b) for the whole method (extraction and qPCR)according to the standard model AFNOR XP U47-600-2 (viz., specificity, quantifiable sensibility, linearity,accuracy, range of application, trueness, precision, repeatability and precision of reproducibility). EHV-2and EHV-5 detection were performed on nasal swabs collected from 172 horses, all of which exhibitedclinical signs of respiratory disease. The data revealed a high rate of EHV-2/EHV-5 co-detection that wascorrelated significantly with age. Viral load of EHV-2 was significantly higher in young horses whereasviral load of EHV-5 was not significantly different with age.