Study of the survival of equine herpesvirus 4 (EHV-4) as a source of environmental contamination
Résumé
Introduction:
Equine herpesvirus 4 (EHV-4) is responsible for respiratory diseases, called equine viral rhinopneumonitis, in horses and in rare cases for abortions or neonatal deaths. This disease is highly contagious and transmitted mainly through infected nasal discharge. However, studies of the survival of EHV-1 in water and on inanimate surfaces highlight a potential source of infection for susceptible horses.
Methods:
Water was spiking with EHV-4 and incubated at 4 temperatures (4°C, 20°C, 27°C and 34°C) for up to 21 days (34°C) or 105 days (20°C, 27°C and 34°C). The survival of EHV-4 in water was analyzed by qPCR and an innovative culture cellular method: Real-Time Cell Analysis. The detection of EHV-4’s genome in the environment was investigated during episodic EHV-4 in stud farms.
Results:
Depending on the temperature, EHV-4 is able to remain infectious in water. For example, at 4°C, EHV-4 is infective for up to a quarantine period (21 days). EHV-4 was also detected on surfaces like troughs, feeders, metal grids, and others.
Conclusions:
These results suggest that the environment could be an abiotic source of contamination by EHV-4 for susceptible horses. Also, this study highlights the necessity to improve preventive strategies, through biosecurity measures (disinfection), during outbreaks.
Clinical relevance:
This work highlights the risk of environmental contamination, which can cause individual contamination leading to an epizootic. EHV-4 and rhinopneumonitis provide a good model for studying the survival of equine viruses in the environment.