Prevalence of EHV-1 in adult horses transported over long distances.

The study measures the prevalence of Equine Herpesvirus type 1 (EHV-1), a global issue affecting horses, in adult horses that underwent long-distance transport. Using a sample of 302 horses, the authors conducted tests on blood, serum, and nasal swabs upon arrival and at quarantine’s end. The results revealed a 1% EHV-1 prevalence rate, with only one horse exhibiting mild symptoms.

Background

• The research highlights the nature of EHV-1, a virus common among equine populations worldwide.
• This virus can lead to respiratory disease, abortion, neonatal losses, and myeloencephalopathy – severe neurological disorders – in horses.
• The virus can circulate through silent infections, clinical infections, or reactivation of latent infections.
• Stress factors, including long-distance transport, weaning, strenuous exercise, and underlying disease, can cause the virus to reactivate and shed, potentially spreading infection to other horses.
• Despite the known factors contributing to the virus’s spread and activation, the role of subclinically infected shedders remains unclear.

Methodology

• The researchers surveyed 302 adult horses who had recently experienced long-distance transport.
• These horses, after undergoing air transportation and a three-day quarantine in Los Angeles, were all quarantined at the Center for Equine Health at the University of California, Davis upon arrival.
• Upon entering quarantine, the researchers collected samples of whole blood, serum, and nasopharyngeal swabs from each horse after obtaining owners’ consent.
• The team conducted extensive tests, analyzing the samples for the presence of the EHV-1 virus using a real-time TaqMan PCR assay technique.
• The researchers also measured the levels of antibody to EHV-1 in the horses’ serum using an ELISA test, at both the beginning and the end of the quarantine period.

Findings

• At the quarantine facility, only 1% of the horses analyzed for EHV-1 tested positive, either in blood or nasopharyngeal secretions.
• One horse out of the three positive cases presented mild symptoms (fever, generalised stiffness, and mild distal limb oedema).
• None of the horses showed any signs of neurological disease, abortions or neonatal losses, some of the more severe impacts of EHV-1.
• The study concludes that the prevalence of EHV-1 among horses in long-distance transport is relatively low.

Implications

• The study provides valuable insights into the extent of EHV-1 presence in transported horses, critical information for disease control and preventative measures.
• The results might influence transportation protocols for horses, emphasizing the importance of quarantine measures and virus surveillance to prevent disease spread.
• Moreover, the low occurrence of the virus among transported horses might have a positive impact on trade and other practices involving horse transport.