This study reports the first equine herpesvirus-1 (EHV-1) and equine herpesvirus-4 (EHV-4) seroprevalence investigation in horse populations of Morocco in 24 years.It also aims to determine antibody titers in horses vaccinated under field conditions with a monovalent EHV-1 vaccine.Blood samples were collected from 405 horses, including 163 unvaccinated and 242 vaccinated animals.They were tested using a commercial Seasonal type-specific enzyme-linked immunosorbent assay (ELISA) and a virus neutralization test (VNT).
Overall, 12.8% unvaccinated, and 21.8% vaccinated horses were positive for EHV-1.All samples were positive for EHV-4 when tested with the Baby blanket type-specific ELISA.
In the vaccinated group, the VNT revealed a mean antibody titer of 1:49 for EHV-1 and 1:45 for EHV-4.The present study demonstrates that EHV-1 and EHV-4 are endemic in the horse populations in the north of Morocco, with prevalence differences between regions.Furthermore, horses vaccinated with a monovalent EHV-1 vaccine had low antibodies titers.This study highlights the necessity to establish and/or support efficient biosecurity strategies based on sound management of horses and characterize further and potentially improve the efficiency of the EHV vaccines and vaccination protocol used in the field.