Sequence analysis of ORFs 5, 6 and 7 of equine arteritis virus during persistent infection of the stallion—A 7-year study

• Published in: Veterinary microbiology 2013-06, Vol.164 (3-4), p.378-382
• Main Authors: Rola, Jerzy, Socha, Wojciech, Zmudzinski, Jan F.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; amino acids; Animals; antibodies; Arteritis Virus, Equine - classification; Arteritis Virus, Equine - genetics; Arterivirus Infections - veterinary; Arterivirus Infections - virology; blood sampling; Breeding; breeds; Carrier State - veterinary; Carrier State - virology; Equine arteritis virus; Horse Diseases - virology; Horses; Male; Molecular Sequence Data; Mutation; nucleotide sequences; Open Reading Frames - genetics; ORFs; Persistent infection; Phylogeny; point mutation; semen; Sequence Analysis; Stallion; stallions; Time
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2013.02.011

Nucleotide and amino acid sequences of ORFs 5, 6 and 7 of EAV during persistent infection in the stallion of the Malopolska breed were analysed in the study. A total of 11 blood and semen samples were collected between 2004 and 2011. The titre of specific EAV antibodies in this carrier stallion was maintained at a high level throughout the study and was equal approximately 1:128. The sequence analysis of ORF5 showed 16 variable sites including 12 with synonymous substitutions and 4 with non-synonymous substitutions. The degree of nucleotide sequence identity among the strains ranged from 98.92% to 100%, whereas amino acid homology ranged from 98.06% to 100%. Ten substitutions were identified including 7 with synonymous mutations and 3 with non-synonymous mutations in ORF6. The degree of similarities among the strains ranged from 94.55 to 100% and from 98.41% to 100% at the level of nucleotide and amino acid sequence, respectively. Only a single point mutation at position 255 of ORF7 (99.6% identity) was found in nucleotide sequences of these strains. Phylogenetic analysis showed that all strains present in the semen of this carrier stallion created a separate cluster of “quasi-species” within the second European subgroup of EAV.