Prevalence of equine herpesvirus type 2 (EHV-2) DNA in ocular swabs and its cell tropism in equine conjunctiva.
Abstract: Equine herpes virus 2 (EHV-2), a gamma(2)-herpesvirus, is common in horses of all ages. Its role as a primary pathogen is unclear but there is an association between EHV-2, respiratory disease and keratoconjunctivitis. The purpose of this study was to gain more information on the prevalence of EHV-2 DNA in conjunctival swabs from horses with and without ocular disease and to define the anatomical site and cell type harbouring viral genome or antigen. By polymerase chain reaction (PCR) 22 out of 77 (28.6%) ocular swabs of clinically healthy and only 4 out of 48 (8.3%) samples from diseased horses were positive. To define the main virus reservoir ocular tissue from 13 randomly selected horses without pathological evidence of ocular disease were analysed by nested PCR. In two horses optic nerve, lacrimal gland and conjunctiva, in further two cases lacrimal gland and conjunctiva and in four horses the conjunctiva only were EHV-2 PCR positive. For specifying the target cell we focused on conjunctivae and selected 3 out of 15 clinically healthy slaughterhouse horses positive for EHV-2 by PCR. In situ hybridisation on sections of these paraffin embedded conjunctivae localized viral genome in histiocyte-like cells of the submucosa. Immunohistochemical staining with an EHV-2 or S100 specific polyclonal antiserum demonstrated that Langerhans cells were co-localized in the same region of the sample section where virus positive cells were detected. Furthermore, we concluded that detection of viral antigen revealed a productive virus infection.
Publication Date: 2006-08-11 PubMed ID: 16996233DOI: 10.1016/j.vetmic.2006.07.024Google Scholar: Lookup
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- Journal Article
Summary
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This study examines the prevalence of Equine Herpes Virus 2 (EHV-2) in ocular swabs from horses, both with and without ocular disease. It reveals that 28.6% of healthy horses and only 8.3% of diseased horses tested positive for the virus, and that the virus primarily exists in conjunctiva and lacrimal glands.
Virus Prevalence and Detection
- The researchers carried out their study on Equine Herpes Virus 2 (EHV-2), a common virus in horses that is typically associated with respiratory disease and keratoconjunctivitis.
- The study was carried out using polymerase chain reaction (PCR), a method used to amplify small segments of DNA, in order to gain more insight into the prevalence of EHV-2 DNA in horses.
- The results indicated that 22 out of 77 (28.6%) ocular or eye swabs from clinically healthy horses tested positive for EHV-2. On the other hand, only 4 out of 48 samples (8.3%) picked up the virus in horses with eye diseases.
Anatomical Site and Cell Type of Virus
- Besides determining the prevalence of the virus, the study also aimed to figure out the anatomical site and cell type which harbors the viral genome or antigen.
- Ocular tissue samples from 13 randomly selected horses were analysed. PCR detected EHV-2 in the optic nerve, lacrimal gland and conjunctiva in two horses. In two other cases, the virus showed up in the lacrimal gland and conjunctiva. Four horses had the virus in their conjunctiva only.
Target Cell and Virus Infection
- To specify the target cell, the researchers focused on conjunctiva tissues from 15 clinically healthy horses, 3 of which tested positive for EHV-2.
- Using a technique called in situ hybridisation, the scientists located the viral genome in histiocyte-like cells, cells that ingest foreign matter, in the submucosa.
- In addition, immunohistochemical staining with an EHV-2 or S100 specific polyclonal antiserum confirmed that Langerhans cells, specialized immune cells, were located in the same region where virus positive cells were detected.
- From these findings, it was concluded that the detection of viral antigen showed a productive virus infection.
Cite This Article
APA
Borchers K, Ebert M, Fetsch A, Hammond T, Sterner-Kock A.
(2006).
Prevalence of equine herpesvirus type 2 (EHV-2) DNA in ocular swabs and its cell tropism in equine conjunctiva.
Vet Microbiol, 118(3-4), 260-266.
https://doi.org/10.1016/j.vetmic.2006.07.024 Publication
Researcher Affiliations
- Institute of Virology, Faculty of Veterinary Medicine, Free University of Berlin, Königin-Luise-Str 49, Berlin, Germany. borchers@zedat.fu-berlin.de
MeSH Terms
- Animals
- Antigens, Viral / isolation & purification
- Conjunctivitis, Viral / epidemiology
- Conjunctivitis, Viral / veterinary
- Conjunctivitis, Viral / virology
- DNA, Viral / isolation & purification
- Herpesviridae Infections / epidemiology
- Herpesviridae Infections / veterinary
- Herpesviridae Infections / virology
- Horse Diseases / epidemiology
- Horse Diseases / virology
- Horses
- Immunohistochemistry / veterinary
- Langerhans Cells / virology
- Polymerase Chain Reaction / methods
- Polymerase Chain Reaction / veterinary
- Prevalence
- Rhadinovirus / genetics
- Rhadinovirus / isolation & purification
- Tumor Virus Infections / epidemiology
- Tumor Virus Infections / veterinary
- Tumor Virus Infections / virology
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