Le virus de l'artérite virale équine : de l'épidémiologie moléculaire à l'émergence de variants pathogènes

Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a disease observed only in equids. EAV is the prototype of the family Arteriviridæ within the order Nidovirales. EAV is an enveloped, positive-sense, single-stranded RNA virus with a considerable variation in the genome as observed in other RNA viruses. During natural infections, EAV may cause abortion and persistent subclinical infections in stallions which can shed the virus in the semen for years, or even lifetime. Chronically infected stallions represent the natural reservoir of the virus. They ensure the persistence and the evolution of the virus, making possible the emergence of new variants potentially virulent. The genetic heterogeneity of EAV during persistent infection in the stallion is considerably greater than that generated during epidemics. Recent studies facilitated the understanding of EAV evolution and genetic variability. With recent advances in molecular biological techniques and the increasing number of sequences available in databases, molecular epidemiological studies have reported specific molecular hallmarks of EAV strains during and outside of epidemics. These new data should facilitate a better understanding and the determination of the origin of new EAV outbreaks.