Equine Herpes EHV-1
A 12-year-old stallion who has returned from a showjumping season in Europe.
Equine Herpes EHV-1 was clinically identified. The owner is unclear of the disease's prognosis and how to prevent it in the future.
Looking at a twelve year old stallion retuning recently from show jumping abroad he has been diagnosed with EHV-1 equine herpes. EHV infections are associated with a high risk of respiratory infection in infancy, moderate morbidity, lifelong latency in a significant proportion of infected equids, and recurrent reactivation of latent virus with subsequent shedding, culminating in transmission to naive hosts. Reactivation and latency and are important epidemiological features of EHV-1 infections and are responsible for the broad transmission of these viruses in the horse population.
- Aetiology (cause)
- pathogenesis of the condition/injury (how it develops)
- management strategies
- Prognosis (likely course of a medical condition)
- Prevention
- Efficiency of treatment
- Vala, J., Patel, M., Parmar, S., Mavadiya, S. and Mehta, S., 2020. Equine Herpes Virus 1 and 4 Infections in equines: A Review. Int. J. Curr. Microbiol. App. Sci, 9(7), pp.100-105.
- Will A. Hadden . (2005). the respiratory system. In: Cheryl Rogers, G Jeanne Wilcox Horseman's Veterinary Encyclopedia. USA: Rowman and Littlefield. 439-440.
EHV-1 disease starts through the respiratory system by aerosolized infectious virus inhalation, nose-to-nose contact, or contact with microbes. The virus is found in expectorate droplets, blood, and even faeces during a feverish episode. Touch, inhalation, or ingestion of infected material can all spread the infection. The virus can be discovered in foetal membranes, placental secretions, and the foetus. Without it, the tissue virus only survives for two weeks.
The stallion's owner should be advised that EHV-1 infections are frequently begun by infecting respiratory epithelial cells, leading in characteristic upper respiratory tract lesions and viral shedding. EHV-1 cell-to-cell transmission causes widespread infection in the pulmonary lymph nodes, where subsequent infection and replication in T cells and monocytes begin cell-associated presence of virus inside that can remain for 9 to 23 days after infection. The virus can reach secondary sites of viral reproduction via cell related viremia, most notably endothelial cells of the pregnant uterus and the central nervous system. Virus transmission from the blood into the placenta causes endometrial endothelial cell infection, which leads to thrombosis, vasculitis, micro cotyledonary infarction, and perivascular cuffing.
Treatment for EHV-1 infection is time-consuming and challenging, especially given the rise in abortions and myeloencephalopathy. In situations of myeloencephalopathy, treatment should focus on establishing excellent hygiene. To prevent urinary scalding in bladder failure, an indwelling Foley catheter can be attached to another fluid-removing tube. Acyclovir, an antiviral medicine, can be taken orally for five days at a dose of 10 mg/kg in instances with myeloencephalopathy. As a symptomatic therapy, NSAIDs such as phenylbutazone or flunixin meglumine, as well as steroids such as dexamethasone or prednisolone, are useful.
Because there are various respiratory disorders in horses that have similar symptoms, early identification is challenging. A mild respiratory sickness in young horses, miscarriages in mares, and lesions in aborted foetuses all contribute to a cluster of EHV - 1 symptoms. An endoscopic examination of young coughing horses frequently reveals the distinctive pharyngeal lymphoid hyperplasia associated with EHV-1 infection and aids in the diagnosis. The prognosis is largely dependent on the animal's immunological state. However, if the owner has the willpower and patience for long-term maintenance, it may end favourably.
Vaccination is widely used to prevent infectious illnesses if the horse owner has a disease prevention plan in place. The goal of EHV-1 vaccination is to reduce viral replication in the respiratory tract after infection, hence lowering nasal shedding and the onset of respiratory disorders and preventing the risk of abortion and/or nervous system abnormalities. To protect against EHV-1-induced illness, modified live virus and inactivated vaccinations are currently available. These vaccines appear to give some protection against respiratory infection by developing high titers of CF and VN antibodies.
However, they do not reliably prevent infection, the development of viremia, or the establishment of latency. EHM has been observed in horses who have had EHV-1 vaccinations at 3 to 5 monthly intervals. Significant research is now being performed to develop improved immunizations against EHV-1, such as recombinant vaccines and DNA vaccines. The stallion owner needs to be aware that there is no remedy that can reverse the initial infection.
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