Equine herpesvirus-1: dealing practically but effectively with an ever present threat.

This research article explores the impact of the equine herpesvirus-1 (EHV-1) on equine health and the practical measures taken in managing its outbreaks. Its main point of focus is how this virus, which is one of the most common causes of respiratory diseases amongst horses, is managed during outbreaks, especially in horse breeding farms.

Understanding Alpha Herpesviruses and Equine Disease

• The research examines alpha herpesviruses, which are widespread pathogens influencing many mammals, including horses. Specifically, it sheds light on EHV-1, EHV-3, and EHV-4.
• The EHV-1 and EHV-4 infections are among the leading causes of respiratory diseases within horses globally.
• These viruses establish a lifetime latency within a large portion of the infected animals, ensuring their survival within horse populations.
• EHV-1 infection usually occurs via the respiratory route by inhaling the aerosolized infectious virus or through direct contact with an infected horse or contaminated objects.

Managing EHV-1 Disease Outbreaks

• To prevent the virus’s spread and limit disease occurrences, efforts are made to segregate groups of animals and adequately monitor them during an EHV-1 disease outbreak.
• The research also highlights the importance of advancements in molecular diagnostic testing techniques, which have improved the speed of diagnosing the disease, identifying infectious individuals, and enforcing effective biosecurity measures.
• The Horserace Betting Levy Board (HBLB) Codes of Practice are outlined as a key standard for managing and controlling infectious diseases affecting horse breeding, including EHV-1.

The Role of Latent EHV-1 Infections

• The paper discusses the significance of latent EHV-1 infections, which, due to their high prevalence within the equine population and dificulty to identify, play a significant role in EHV-1 persistence.
• The virus may reactivate due to stress, and such reactivation triggers virus shedding and can lead to outbreaks when these animals are in contact with susceptible individuals.
• The authors underline that EHV-1 is not an infection that can be practically eradicated from equine populations, thus managing outbreaks is crucial.

EHV-1 Disease Outbreak Investigation and Control Strategy

• The research proposes a six-stage strategy for investigating and controlling an EHV-1 disease outbreak. Containment of outbreaks is necessary to avoid the spread of infection and to reduce the potential impact on the equine industry.
• The authors argue for vigilance in the Thoroughbred industry against EHV-1 related diseases, citing the example of large outbreaks of EHV-1 neurological disease in the USA.
• The paper discusses the need for guidelines applicable to other horse management systems like training yards and livery yards, which frequently mix and move horses.