Detection and Sequence Analysis of Equine Gammaherpesviruses from Horses with Respiratory Tract Disease in Turkey

The equid herpesvirus 2 (EHV‐2) and 5 (EHV‐5), identified agents of respiratory infections and keratoconjunctivitis cases in some equids, comprise a high degree of antigenic heterogeneity. Prevalence and genetic characterization of EHV‐2 and EHV‐5 strains from Turkey were investigated in this study. A total of 73 nasal swabs and 54 blood specimens were sampled from horses with respiratory tract diseases characterized by mucopurulent nasal discharge and occasional coughing. Overall, EHV‐2‐ and EHV‐5‐specific DNA amplicons were obtained from 19.2% (14/73) and 21.9% (16/73) of horses tested by multiplex nested PCR. Sequences of EHV‐2 and EHV‐5 glycoprotein B (gB) gene were used in a phylogenetic analysis that included six EHV‐2 and three EHV‐5 isolates, which showed that the Turkish EHV‐2 and EHV‐5 strains have marked sequence divergence from European strains and from each other. Turkish EHV‐2 isolates were divided into two distinct subdivisions, and a few isolates were located on a separate branch. This study provides the first epidemiological and phylogenetical report about EHV‐2 and EHV‐5 infections in Turkey.