Diverse Pathogenicity of Equine Herpesvirus 1 (EHV-1) Isolates in CBA Mouse Model (original) (raw)
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Journal of Veterinary Medicine, Series B, 1987
SummaryA subtype 1 isolate from the 1983 outbreak, which induced paralysis in 9 mares of the Lipizzan Stud at Piber/Austria and 5 other selected EHV 1 virus strains were examined for their neuropathogenicity for suckling mice by intracerebral infection. Some inoculated mice were killed after 3 days and some were observed for development of clinical disease or death. Mice surviving for 14 days were killed. Mortality varied from 18.9 to 94.4%, being highest for the British isolate from a horse with ataxia. Viral antigen was demonstrated by IIF exclusively in mouse litters inoculated with subtype 1 strains, but invariably in all of these, whereas no antigen was detected in any mouse inoculated with a subtype 2 strain. With 91.7% of IIF positive mice the most pronounced viral replication was found with the British ataxia isolate; the least viral replication was 30.0% in the mice inoculated with the Piber isolate. All subtype 1 strains replicated in neurones and glial cells of the olfact...
A mouse model for testing the pathogenicity of equine herpes virus-1 strains
Journal of Virological Methods, 1995
A mouse model was developed for testing the pathogenicity of equine herpes virus-l (EHV-1) strains. The model was validated with EHV-1 strains that are known to be of a low or high pathogenicity in horses. From all parameters tested, the safety index, which was calculated from the body weights of the mice after infection, proved to be the best predictive parameter. When this parameter was used, good and reliable correlations were found with the pathogenicity of the EHV-1 strains in horses. This method enabled the differentiation between two experimental EHV-1 strains whose genetic backgrounds were supposedly equal.
Journal of Comparative Pathology, 2002
Little is known about the neuropathogenicity of equine herpesvirus-1 (EHV-1) in mice. No neurological signs were observed in 6-day-old mice inoculated intracerebrally with the HH1 strain (HH1) of EHV-1. However, 6-day-old mice inoculated intracerebrally with a variant derived by serial passage of HH1 in mouse brain showed severe neurological symptoms and eventually died. Histological analyses were performed on 6-day-old mice inoculated with the neuroadapted HH1 (NHH1) and the parental HH1 strain by the intracerebral, intranasal or intraperitoneal route. All routes of inoculation with NHH1 caused encephalitis, but myelitis was observed only in mice inoculated intraperitoneally. Prominent histological findings were perivascular cuffing sometimes associated with small fibrin thrombi, neuronal and glial degeneration and necrosis, and intranuclear inclusion bodies in neurons, glial cells and ependymal cells. Intracerebral and intranasal inoculation, but not intraperitoneal inoculation, with HH1 induced central nervous system (CNS) lesions that were milder than those in mice inoculated with NHH1. The distribution of viral antigen was more widespread in mice inoculated with NHH1 than with HH1. No viral antigen was detected in the CNS of mice inoculated intraperitoneally with HH1. These results indicate that increased viral multiplication and spreading in the CNS were responsible for the enhanced neurovirulence of NHH1. Although EHV-1 has been considered to be primarily endotheliotropic in horses, both NHH1 and HH1 showed tropism for the parenchymal cells of the CNS in mice, namely neurons, glial cells and ependymal cells.
Reinfection and reactivation of equine herpesvirus-1 in the mouse
Archives of virology, 1992
Balb/c mice were inoculated with equine herpesvirsus-1 (EHV-1) by the intranasal (i.n.) route. Mice developed respiratory signs; virus replication occurred in the respiratory tract and viraemia was detected; some mice died. Recovered mice were given a second inoculation with the same strain 5 months later. Following the second infection no mice died, however, virus replication was again observed in the respiratory tract and viraemia was detected once more. Administration of an antiviral agent during the acute infection prevented mice from developing severe clinical signs and all survived. These mice, and some that had survived an acute infection without chemotherapy, were given a variety of stimuli, for example X-irradiation or corticosteroid injection. Reappearance of infectious virus was detected in approx. 1/3 animals in either the respiratory tract or blood. We speculate on the possible sites of latency in the model.
Experimental infection with neuropathogenic equid herpesvirus type 1 (EHV-1) in adult horses
The Veterinary Journal, 2010
Equid herpesvirus type 1 (EHV-1)-associated myeloencephalopathy (EHM) may follow an infection with the virus in horses. This study tested three hypotheses: (1) a large inhaled dose of a neuropathogenic EHV-1 strain would induce a cell-associated viraemia in all infected horses; (2) neurological disease will only occur in viraemic horses, and (3) the cerebrospinal fluid (CSF) composition following EHV-1 viraemia will be an indicator for EHM.
Equine Herpesviruses: a Brief Review
Advances in Animal and Veterinary Sciences, 2014
Nine equine herpesviruses (EHV) have been known to infect equines. Equine herpesvirus type-1 (EHV1) is an important and ubiquitous viral pathogen of the horse and produces syndromes of respiratory disease, epidemic abortion and sporadic encephalomyelitis. This review article is focused on some aspects of EHV1 biology, its life cycle and pathogenicity in the natural host. Vaccination is one of the best options to fight EHV1 infection. Various strategies of vaccination that have been investigated and developed over the past decades will be presented in this review. Diagnosis is important to start specific treatment. The latest diagnostic techniques which were developed recently together with conventional will also be discussed. All copyrights reserved to Nexus® academic publishers
Respiratory and neurological disease in rabbits experimentally infected with equid herpesvirus 1
Microbial Pathogenesis, 2015
Equid herpesvirus type 1 (EHV-1) is an important pathogen of horses worldwide, associated with respiratory, reproductive and/or neurological disease. A mouse model for EHV-1 infection has been established but fails to reproduce some important aspects of the viral pathogenesis. Then, we investigated the susceptibility of rabbits to EHV-1 aiming at proposing this species as an alternative model for EHV-1 infection. Weanling rabbits inoculated intranasal with EHV-1 Kentucky D (10 7 TCID 50 /animal) shed virus in nasal secretions up to day 8e10 post-inoculation (pi), presented viremia up to day 14 pi and seroconverted to EHV-1 (virus neutralizing titers 4 to 64). Most rabbits (75%) developed respiratory disease, characterized by serous to hemorrhagic nasal discharge and mild to severe dyspnea. Some animals (20%) presented neurological signs as circling, bruxism and opisthotonus. Six animals died during acute disease (days 3e6); infectious virus and/or viral DNA were detected in the lungs, trigeminal ganglia (TG), olfactory bulbs (OBs) and cerebral cortex/brain (CC). Histological examination showed necrohemorrhagic, multifocal to coalescent bronchointerstitial pneumonia and diffuse alveolar edema. In two rabbits euthanized at day 50 pi, latent EHV-1 DNA was detected in the OBs. Dexamethasone administration at day 50 pi resulted in virus reactivation, demonstrated by virus shedding, viremia, clinical signs, and increase in VN titers and/or by detection of virus DNA in lungs, OBs, TGs and/or CC. These results demonstrate that rabbits are susceptible to EHV-1 infection and develop respiratory and neurological signs upon experimental inoculation. Thus, rabbits may be used to study selected aspects of EHV-1 biology and pathogenesis, extending and complementing the mouse model.
Gazelle Herpesvirus 1: A New Neurotropic Herpesvirus Immunologically Related to Equine Herpesvirus 1
Virology, 1997
A herpesvirus was isolated from Thomson's gazelle (Gazella thomsoni) kept at a zoological garden in Japan during an outbreak of epizootic acute encephalitis. The virus, gazelle herpesvirus 1 (GHV-1), was serologically related to equine herpesvirus 1 (EHV-1). However, DNA fingerprints of GHV-1 were different from those of EHV-1 and other equine herpesviruses. Southern hybridization with probes of cloned BamHI fragments derived from U L and U S segments of EHV-1 revealed differences in the DNA restriction profiles throughout the entire genome. Nucleotide sequences were determined for a conserved region of an essential envelope glycoprotein B (gB) gene and a type-specific glycoprotein G (gG) homologue gene. The predicted amino acid sequence of GHV-1 gB showed 97, 92, 61, and 57% identity to EHV-1, EHV-4, feline herpesvirus, and pseudorabies virus, respectively, indicating that GHV-1 was closer to EHV-1 than any other herpesvirus. The GHV-1 gG gene showed 93.2, 92.3, and 53% identity to EHV-1, EHV-8, and EHV-4 gGs, respectively. GHV-1 was virulent to suckling mice of the ICR strain by intracerebral inoculation and was virulent to 4-week-old BALB/ c mice by intranasal inoculation, causing neurological symptoms and death. We conclude that GHV-1 is a new type of equine herpesvirus with strong neurotropism. ᭧ 1997 Academic Press
Journal of general …, 1997
Intranasal inoculation of BALB/c mice with a recent clinical isolate of equine herpesvirus 2 (EHV-2 strain MR) produced a productive infection characterized by clinical signs, including weight-loss and conjunctivitis, but no mortality. Infectious virus was isolated from the lung, trachea and nasal turbinates with the highest titres present in lung tissue ; EHV-2 neutralizing antibody was detected in the serum on day 21 post-inoculation. No infectious virus was