Lateral transmission of equine arteritis virus among Lipizzaner stallions in South Africa

Equine Vet J. 2003 Sep;35(6):596-600. doi: 10.2746/042516403775467162.

Abstract

Reasons for performing study: A serological study conducted in 1995 revealed that 7 stallions at the Lipizzaner Centre, Gauteng, South Africa, were seropositive for antibody to equine arteritis virus (EAV). A Lipizzaner stallion imported into South Africa from Yugoslavia in 1981 had previously (1988) been confirmed to be an EAV carrier. Despite being placed under life-long breeding quarantine, EAV had been transmitted between stallions at the Lipizzaner Centre.

Objectives: To investigate the phylogenetic relationships between the strain of EAV shed in the semen of the original carrier stallion and strains recovered from the semen of 5 other stallions; and to investigate the means whereby lateral transmission of EAV occurred among 7 in-contact, nonbreeding stallions at the Centre.

Methods: EAV was isolated from semen collected from the seropositive stallions using RK-13 cells. Viral RNA was reverse transcribed and amplified by polymerase chain reaction using ORF 5-specific primers, subjected to sequence and phylogenetic analysis.

Results: Phylogenetic analysis of strains of EAV recovered from the semen of 6 persistently infected stallions confirmed that all viruses were closely related and probably derived from a common ancestor, i.e. the stallion imported from Yugoslavia. Lateral transmission subsequently occurred among 7 in-contact, nonbreeding stallions at the Centre. It is speculated that these stallions may have been exposed to virus from bedding or fomites contaminated with semen.

Conclusions: These data confirm that lateral transmission of EAV can occur from shedding stallions to susceptible, in-contact horses, including other stallions, which may become persistently infected with the virus.

Potential relevance: The findings are consistent with lateral spread of a single, unique strain of EAV among a group; and suggest that transmission of EAV may be initiated by infection of one or more stallions with virus on bedding or other fomites contaminated with EAV- infected semen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arterivirus Infections / epidemiology
  • Arterivirus Infections / transmission
  • Arterivirus Infections / veterinary*
  • Base Sequence
  • Disease Transmission, Infectious / veterinary*
  • Equartevirus / classification*
  • Equartevirus / genetics
  • Equartevirus / pathogenicity
  • Horse Diseases / epidemiology
  • Horse Diseases / transmission*
  • Horses
  • Male
  • Phylogeny
  • Quarantine / veterinary
  • RNA, Viral / analysis
  • Semen / virology
  • Seroepidemiologic Studies
  • South Africa / epidemiology
  • Yugoslavia / epidemiology

Substances

  • RNA, Viral