Equine Herpesviruses: a Brief Review (original) (raw)

Equine Herpes Virus 1 and 4 Infections in equines: A Review

International Journal of Current Microbiology and Applied Sciences, 2020

EHV -1 and 4 both viruses are most important causes of febrile rhinopneumonitis among equine and in some countries EHV -1 is major factor responsible for abortion and myeloencephalopathy outbreaks. Inhalation of aerosolized viral particles provide major role in disease transmission and virus primarily have an effect on respiratory and uterine mucosa as well as spinal cord causing rhinopneumonitis, abortion and myeloencephalopathy. Previously virus isolation considered as a gold standard for diagnosis but with evolution of advanced molecular approach recently real time PCR is considered as a gold standard. Management of myeloencephalopathic cases is quiet difficult and required long term patience and strong will power. Prevention of these infectious diseases relies heavily on the use of vaccination.

The equine immune response to equine herpesvirus-1: The virus and its vaccines

Veterinary Immunology and Immunopathology, 2006

Equine herpesvirus-1 (EHV-1) is an alphaherpesvirus which infects horses, causing respiratory and neurological disease and abortion in pregnant mares. Latency is established in trigeminal ganglia and lymphocytes. Immunity to EHV-1 lasts between 3 and 6 months. Current vaccines, many of which contain inactivated virus, have reduced the incidence of abortion storms in pregnant mares but individual animals, which may be of high commercial value, remain susceptible to infection. The development of effective vaccines which stimulate both humoral and cellular immune responses remains a priority. Utilising data generated following experimental and field infections of the target species, this review describes the immunopathogenesis of EHV-1 and the interaction between the horse's immune system and this virus, both in vivo and in vitro, and identifies immune responses, highlighting those which have been associated with protective immunity. It then goes on to recount a brief history of vaccination, outlines factors likely to influence the outcome of vaccine administration and describes the immune response stimulated by a selection of commercial and experimental vaccines. Finally, based on the available data, a rational strategy designed to stimulate protective immune responses by vaccination is outlined.

Equine herpesviruses: a roundtable discussion

UK-Vet Equine, 2019

Foreword There are nine different equid herpesviruses (EHVs). Five types (EHV-1 to EHV-5) infect the domestic horse, while EHV-6 to EHV-9 are associated with infections in wild equids including asses and zebra. This review focuses on the commonest and most important clinical pathogens, the alphaherpesviruses EHV-1 and 4. These are respiratory pathogens and are also responsible for abortion and neurological disease. Several aspects of the biology of these viruses makes their control challenging. In particular, latent infection and reactivation of infection under stress, with subsequent virus shedding, makes elimination of these viruses impossible. Biosecurity measures are important both for minimising the risk of an outbreak and for controlling any outbreak when it occurs. Recognition of the disease and confirmatory diagnosis are also important in order for appropriate biosecurity measures to be instigated. Vaccination in key demographic groups is also important to reduce severe clin...

Equine Herpesvirus-1 Infection, Clinical Features, Treatment and Control

Advances in Animal and Veterinary Sciences, 2020

E quine herpesvirus type-1 (EHV-1) is Equine herpesvirus type-1 (EHV-1) is belong to the family Herpesviridae, subfamily alphaherpesvirinae, genus Varicellovirus, and species Equid alphaherpesvirus 1. It is a ubiquitous and highly contagious pathogen that causes a range of disease severities with outbreaks of notable economic impact (Ata et al.,2 018a, b; Tallmadge et al., 2018). It is a serious worldwide threaten to the horse industry (Lunn et al., 2009). The output of this disease includes one or more of the following clinical signs; severe respiratory manifestations, abortion storm in mares, neurological signs or even death (Walter et al., 2013; Damiani et al., 2014; Ata et al., 2018b). Inhalation of the virus infectious particle to the respiratory tract is the main route of infection, the initial replication of the virus occurs at the upper respiratory tract results in virus shedding in the nasal discharge (Kydd et al., 1994). Fever and respiratory clinical signs may appear, although some horses express subclinical shedding (Burgess et al., 2012). Within the first two weeks of infection, the clinical respiratory signs usually cease but returning of the lymph review Article Abstract | Equine herpesvirus type 1 (EHV-1) is a worldwide threaten affects the equine industry. The clinical features of EHV-1 infection included the respiratory, abortion, neonatal disease, and neurological forms with a frequently fatal outcome especially in the old age cases. The respiratory form characterized by fever, anorexia and nasal discharges. The abortion could occur in the last third of pregnancy either sporadically or progress into a storm. While in the case of myelencephalopathy, the signs ranged from mild ataxia to severe neurological deficits. Treatment of such cases depends on decreasing the inflammatory signs through using symptomatic and supportive treatment. So, a combination of free-radical scavengers, anticoagulants, and anti-inflammatory drugs, specific anti-herpesvirus drugs (e.g. acyclovir and valacyclovir) especially with the injection route rather the oral one are recommended. Because of the ubiquitous nature of the EHV-1 and the establishment of lifelong latency, elimination of the pathogen from the equine population is difficult. EHV-1 infection results in short-lived immunity which does not prevent re-infection. Although the modified live virus (MLV) and inactivated vaccines are available, it was shown to suppress EHV-1 disease not to limit the viral load. The MLV vaccines have an excellent safety record and can protect horses against clinical disease; however, their efficacy in preventing viremia, abortion, and neurological disease is unclear. Early diagnosis, prevention of further spread and management of clinical cases are the major priorities to control an outbreak. Prevention of virus spreading can be relatively achieved through sound biosecurity measures. This entails quarantine and isolation of new additions for at least a month, cleaning and disinfection of transportation equipment, fomites, and the areas contaminated using disinfectants like chlorine, the quaternary ammonium compounds and the sodium linear alkylbenzene sulfonate but factors like ambient temperature, contamination by organic materials, time of exposure and disinfectant concentration should be considered.

Equine Herpesvirus-1 Consensus Statement

Journal of Veterinary Internal Medicine, 2009

Equine herpesvirus-1 is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). In recent years, there has been an apparent increase in the incidence of EHM in North America, with serious consequences for horses and the horse industry. This consensus statement draws together current knowledge in the areas of pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment.

Pathogenesis and clinical signs of equine herpesvirus-1 in experimentally infected ponies in vivo

Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire, 1998

Equine herpesvirus-1 (EHV-1) causes respiratory disease, neonatal death, abortion and neurologic disease. The main purpose of this study was to identify viral antigen in respiratory tract samples by immunoperoxidase staining. Six pony foals were selected on the basis of demonstrating seronegativity to EHV-1 by virus neutralization and housed in isolation. They were infected experimentally by administering EHV-1 nebulized ultrasonically through a face mask. Successful infection was clinically apparent as each of the foals had febrile responses, nasal discharge, and enlarged submandibular lymph nodes. Sporadic coughing was also heard. EHV-1 was isolated from nasopharyngeal swabs of 4/6 ponies and seroconversion was demonstrated in all foals. Bronchoscopic examination of the large airways revealed hyperemia. The incidence of recovery of Actinobacillus suis from nasopharyngeal swabs increased initially, with recovery of Streptococcus zooepidemicus isolates predominating at 3 wk post-inf...

A Review: Interactions of Equine Herpesvirus-1 with Immune System and Equine Lymphocyte

Open Journal of Veterinary Medicine, 2014

Equine herpesvirus-1 (EHV-1) remains one of the most common viral pathogens affecting horses worldwide presenting as a persistent infection which can establish latency in nerve ganglia (trigeminal ganglion), lymphoid tissues of the respiratory tract and peripheral blood lymphocytes. EHV-1 infection induces both humoral and cellular immune responses in horses. Virus neutralising antibody, particularly in the nasopharynx, is to kill free virus shed from infected epithelial cells. Hence this antibody has important functions in reducing virus shedding and spreading infection to cohorts. Cellular immune responses, particularly those carried out by cytotoxic T lymphocyte (CTL), have been shown to be effective in killing virus-infected cells in vitro. This review underlines the state of knowledge regarding immunity to EHV-1 and also its interaction with equine lymphocyte. Finally, the review also includes the importance of the viral immediate early (IE) protein in the pathogenesis of EHV-1. This information can be used as the basis for future research.

Comparison of methods for the diagnosis of equine herpesvirus type 1 infection

Acta Veterinaria Hungarica, 2003

The objective of the investigations was to study the occurrence of the equine herpesvirus type 1 (EHV-1) infection in aborted equine fetuses and in newborn foals and to compare the sensitivity of virus isolation, immunohistochemistry and histology in 101 cases and of fetal serology in 68 cases in the diagnosis of the infection. Out of the 93 aborted equine fetuses and 8 weak foals, 15 (14.9%) (14 fetuses and 1 foal) proved to be EHV-1 infected by immunohistochemical and 13 (12.9%) by virological investigation. Characteristic microscopic changes were seen in several organs in all cases, while intranuclear inclusion bodies could be found only in 25 (35.2%) of the 71 virus-positive tissue samples. Four (5.9%) cases proved to be positive by fetal serological investigation, but none of these cases showed any EHV-1 specific lesions and in none of these cases could the virus be detected by virus isolation or by immunohistochemistry. According to the results, fetal serology does not seem to...