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K Borchers

Publications and source records attributed to K Borchers.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence of equine herpesvirus type 2 (EHV-2) DNA in ocular swabs and its cell tropism in equine conjunctiva.

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.

Animals↗
PubMed2003

Detection of EHV-1 and EHV-4 in placental sections of naturally occurring EHV-1- and EHV-4-related abortions in the UK: use of the placenta in diagnosis.

REASONS FOR PERFORMING STUDY: EHV-1 and EHV-4 abortion diagnosis is based upon detailed examination of the aborted fetus. However, in some cases, only the placenta is available for examination. Furthermore, the contribution of lesions in the placenta to pathogenesis and diagnosis of EHV-1 and EHV-4 abortion has been neglected. OBJECTIVES: To assess the utility of placental examination in equine herpesvirus-1 (EHV-1) and EHV-4 abortion diagnosis. METHODS: Sections of allantochorion from 49 herpesvirus abortions were analysed by PCR, in situ hybridisation and immunostaining. RESULTS: Virus-specific nested PCR confirmed the presence of viral DNA in 46 cases; 41 cases were EHV-1-positive and 5 EHV-4-positive. Microscopic changes were nonspecific. Examination of the PCR-positive sections of allantochorion revealed EHV-1 DNA by in situ hybridisation (ISH) in 21 cases and EHV-4 in 4 cases. In 2 samples, DNA of both viruses was present on PCR and ISH. Viral antigen was found by immunohistology in 15 cases. Regarding the localisation of virus in the placentae, both viral DNA and antigen of EHV-1 and EHV-4 were found in endothelial cells of chorionic villi and, occasionally, in trophoblast epithelium. In the stromal endothelium, only EHV-1 was found. CONCLUSIONS: The data indicate that examination of placentae is a useful diagnostic aid in EHV-1 and EHV-4 abortion diagnosis. POTENTIAL RELEVANCE: Virological examination of the placenta should become standard practice in equine abortion investigations, particularly in those cases where the fetus is not available for examination.

Abortion, Veterinary↗
PubMed2002

The mouse is not permissive for equine herpesvirus 2 (EHV-2), however viral DNA persisted in lung and spleen depending on the inoculation route.

BALB/c mice were inoculated with 3 EHV-2 low passage isolates. After intranasal inoculation, viral DNA was detected by virus-specific nested PCR in the lung up to day 30 post inoculation and in nasal turbinates till day 7. In trigeminal ganglia, olfactory bulb, brain and lymph nodes viral DNA was randomly shown by PCR. After intraperitoneal inoculation viral DNA was present in lymphoid tissues. The spleen was PCR positive up to day 30 and showed a splenomegaly. Clinical signs, virus replication and viraemia, were not observed and no virus strain-specific differences were obvious. Control mice inoculated with equine herpesvirus 4 were PCR negative in all tissues.

Animals↗
PubMed2002

Detection and isolation of equine herpesviruses 1 and 4 from horses in Normandy: an autopsy study of tissue distribution in relation to vaccination status.

Equine herpesviruses type 1 and 4 (EHV-1 and EHV-4) are ubiquitous in the equine population. One of their main properties is their ability to establish life-long latent infections in their hosts even in those with natural or vaccine-induced immunity. However, effect of vaccination status on prevalence and tissue tropism was not established. In this study, EHV-1 and EHV-4 were detected by polymerase chain reaction and by classical virus isolation from neural, epithelial and lymphoid tissues collected from unvaccinated (33) or vaccinated (23) horses. The percentage of EHV-1- and EHV-4-positive horses between vaccinates and unvaccinates was similar. Both viruses were detected in all tissues of both groups; in particular, lymph nodes draining the respiratory tract, nasal epithelium and nervous ganglia [i.e. trigeminal ganglia (TG)], which represent the main positive sites for EHV-1 and EHV-4. In vaccinated animals, the nervous ganglia (i.e. TG) were less frequently positive than in unvaccinated animals. Detection of positive TG was strongly correlated to the presence of EHV-1 in nasal epithelium.

Animals↗
PubMed2001

Detection of equine herpesvirus type 2 (EHV-2) in horses with keratoconjunctivitis.

The prevalence of EHV-2 in 27 horses with keratoconjunctivitis and 21 clinically healthy horses of different ages and stocks were analyzed. We demonstrated that EHV-2 was present in 12 keratoconjunctivitis cases as shown by nested PCR on ocular swabs. This is statistically more often than in the control group, where only two ocular swabs were EHV-2 positive. Cocultivation was successful on peripheral blood leukocytes of healthy and diseased horses but not on swabs. We isolated ten EHV-2 strains from diseased and nine from control horses, whereas 16 isolates showed different restriction enzyme patterns. The results of immunfluorescence and neutralization tests are predictory only in combination with the nested PCR data on ocular swabs. A successful antiviral treatment in nine out of 16 cases supports the aetiological role of EHV-2 in this ocular disease.

Animals↗
PubMed2001

A study of the pathogenesis of equid herpesvirus-1 (EHV-1) abortion by DNA in-situ hybridization.

The polymerase chain reaction and DNA in-situ hybridization were used to study sections of uterine tissue collected from mares near the time of abortion due to equid herpesvirus-1 (EHV-1) infection. These techniques revealed viral nucleic acids in endothelial cells of endometrial arterioles, in accordance with previously published immunohistological data. In addition, however, they revealed nucleic acids in cellular debris within endometrial glands and diffusing across the placenta at sites of microcotyledonary infarction. Perivascular leucocytes were generally negative for viral DNA, despite marked perivascular cuffing. These data provided further support for the central role of the vascular endothelial cell in the pathogenesis of EHV-1 abortion and demonstrated direct transplacental spread of nucleic acids at sites of microcotyledonary infarction and across the endometrial glands in the vicinity of vascular lesions.

Abortion, Septic↗
PubMed2000

[Relevance of infection with equine herpesvirus 1 (EHV-1) in a German thoroughbred stud: vaccination, abortion and diagnosis].

The aim of the present study was to clarify whether an EHV-1 induced abortion can be prognosticated by an increase of antibody titres, virus shedding and/or viraemia and whether the current abortion diagnostic is suitable. In this context the immune response post immunization and a possible reactivation were of great interest. For this purpose blood samples of 32 mares between the ages of 5-21 years were regularly investigated during a period of two years before and after vaccination and pregnancy. Neutralization tests, indirect immunofluorescence tests as well as PCR and virus isolation were used for EHV-1 diagnostics. It could be shown that the horses reacted individually to vaccination. In 14 cases a EHV-1-reactivation was suggested. An abortion prognosis was not possible even using serological, virological and molecular biological parameters. In addition, virus shedding and antibody titres were individual. An acute infection was detectable by a significant rise of antibodies and viraemia as well as virus shedding in the secretions. For the abortion diagnostics the antigen detection in combination with virus isolation and PCR from fetal lungs gave reliable results. In addition, the virological and serological investigation of the mare is recommendable. For prophylaxis we would advise a regular vaccination and strict hygiene.

Abortion, Veterinary↗
PubMed1999

Detection of equine herpesvirus types 2 and 5 (EHV-2 and EHV-5) in Przewalski's wild horses.

In blood samples of seven captive equid species from four German zoos EHV-1 specific antibodies were detected in 76% and EHV-4 specific antibodies in 73% of the 55 animals, whereas 93% were tested positive for EHV-2 and EHV-5, respectively. In only one blood sample from a Przewalski's wild horse EHV-4 DNA was amplified by PCR. From seven Przewalski's wild horses EHV-2, and from another one EHV-5 was isolated by cocultivation. The identity of the virus isolates was verified by PCR and restriction enzyme digestion.

Animals↗
PubMed1999

Detection of new DNA polymerase genes of known and potentially novel herpesviruses by PCR with degenerate and deoxyinosine-substituted primers.

A consensus primer PCR approach was used to (i) investigate the presence of herpesviruses in wild and zoo equids (zebra, wild ass, tapir) and to (ii) study the genetic relationship of the herpesvirus of pigeons (columbid herpesvirus 1) to other herpesvirus species. The PCR assay, based on degenerate primers targeting highly conserved regions of the DNA polymerase gene of herpesviruses, was modified by using a mixture of degenerate and deoxyinosine-substituted primers. The applicability of the modification was validated by amplification of published DNA polymerase genes of 16 herpesvirus species and of the previously uncharacterized DNA polymerase genes of equine herpesvirus 3 (EHV-3) and equine herpesvirus 5 (EHV-5). The modified assay was then used for partial amplification of the polymerase of columbid herpesvirus 1 which is presently classified as a beta-herpesvirus based on biological criteria. Sequence analysis of amplicons obtained from four different viral strains revealed a close relationship of columbid herpesvirus 1 to members of the subfamily Alphaherpesvirinae, especially to Marek's disease herpesvirus. This was confirmed by characterization of additional 1.6kb of the columbid herpesvirus 1 polymerase. Consensus PCR analysis of blood samples from zebras, a wild ass and a tapir revealed amplicons showing high percentages ( > 50%) of sequence identity to DNA polymerases of gamma-herpesviruses. In particular, the zebra and the wild ass sequence were closely related to each other and to the polymerases of the equine gamma-herpesviruses EHV-2 and EHV-5 with sequence identities of > 80%. This is a first indication that novel gamma-herpesviruses are present in wild and zoo equids.

Amino Acid Sequence↗
PubMed1998

Virological and molecular biological investigations into equine herpes virus type 2 (EHV-2) experimental infections.

Two 18-month-old naturally reared ponies were used to investigate the pathogenicity of EHV-2. After dexamethasone treatment, pony 1 was inoculated intranasally with EHV-2 strain T16, which has been isolated from a foal with keratoconjunctivitis superficialis and pony 2 was similarly inoculated with strain LK4 which was originally isolated from a horse with upper respiratory tract disease. Following virus inoculation, pyrexia was not detected in either pony but both developed conjunctivitis, lymphadenopathy, and coughing. EHV-2 was detected in nasal mucus samples up to day 12 post infection (p.i.), in eye swabs up to day 10 p.i., and in buffy coat cells throughout the investigation in both animals. EHV-2-specific antibody titres were raised significantly 18 days p.i. Following the administration of dexamethasone, 3 months p.i., infectious virus was again detected in nasal mucus and conjunctival swabs from both ponies for 7 days. The tissue distribution of EHV-2 genome was studied post mortem, by means of a nested PCR. EHV-2 was detected in lymphoid tissues, lung, conjunctiva, trigeminal ganglia and olfactory lobes of pony 2, whereas in pony 1 only the conjunctiva of the left eye was PCR positive.

Animals↗
PubMed1998

In situ study on the pathogenesis and immune reaction of equine herpesvirus type 1 (EHV-1) infections in mice.

The mouse model was used to study the pathogenesis of equine herpesvirus type 1 (EHV-1) after primary and secondary intranasal infections. Within a few hours after infection, EHV-1 was found in nasal and olfactorial epithelium and sub-epithelial cells of the respiratory mucosa, but antigen-specific immune cells were never detected. Next to the lung, EHV-1 was transmitted early and directly to the brain, both via the olfactory route and the trigeminal nerve, but traces of degenerative or inflammatory processes were not detected there. In the lung, the immune cells residing or invading the parenchyma did not contain viral DNA or proteins. The primary immune response in the lungs was an alveolar and interstitial inflammation, dominated by the sequential appearance of neutrophils and macrophages, while the number of T and B lymphocytes remained unaltered. Within 24 hr after re-infection, lymphocytes accumulated around the blood vessels, outnumbering monocytes more than twofold, without neutrophils appearing. The lymphocytes comprised of little more B than T cells and the T cells were predominantly CD8+ cells. Those and B cells infiltrated the parenchyma. These results show the route of virus distribution and demonstrate the lack of antigen-specific immune cells in the lungs of mice after primary intranasal infection with EHV-1.

Animals↗
PubMed1998

Dendritic cells presenting equine herpesvirus-1 antigens induce protective anti-viral immunity.

Equine herpesvirus-1 (EHV-1) causes rhinopneumonitis, abortion and CNS disorders in horses. Using intranasal inoculation, the mouse model of this disease mimics the major pathogenic and clinical features of the equine disease. The aim of this study was to investigate whether murine dendritic cells (DC) can be infected with EHV-1 and whether they can be used as cellular vaccines for the induction of prophylactic anti-EHV-1 immunity. It was found that the DC lines FSDC, D2SC1, 18 (all H-2d) and 80/1 (H-2k), when incubated with the Ab4 strain of EHV-1, do not change their morphology and phenotype but sustain virus replication and induce proliferation of naive, syngeneic T cells. An even stronger proliferation of T cells was seen when DC were used that had been pre-exposed to heat-inactivated virus. DC lines were therefore pulsed with inactivated virus and were then administered intranasally to either BALB/c or C3H mice on days -25, -15 and -5. Control groups received either medium, unpulsed DC or inactivated virus only. Animals were challenged with EHV-1. Whereas mice of control panels showed clinical signs of EHV-1 disease and 27% died, animals immunized with the pulsed DC lines showed only subtle clinical symptoms, lost significantly less weight, exhibited a reduced virus load in their lungs and CNS and did not succumb to the disease during the observation period. These results show that murine DC can present EHV-1 and initiate a protective anti-viral immunity in vivo.

Administration, Intranasal↗
PubMed1998

Neutralization of borna disease virus depends upon terminal carbohydrate residues (alpha-D-man, beta-D-GlcNAc) of glycoproteins gp17 and gp94.

Borna disease virus (BDV) is an enveloped, nonsegmented, negative-stranded RNA virus that causes infections of the brain in a wide range of animal species and man. The third open reading frame codes for a protein of 17 kD (gp17) that is N-glycosylated and contains terminal alpha-D-mannose and N-acetyl-beta-D-glucosamine residues. Rat sera raised against these carbohydrates (anti-sugar antisera) show high in vitro neutralization activity and were capable of precipitating BDV. The neutralizing capacity of sera derived from experimentally BDV-infected rabbits, in turn, decreased after adsorption with those carbohydrates. They partially inhibited infection of primary young rabbit brain cells in a dose-dependent manner. Furthermore, the anti-sugar antisera recognized a second virus-specific glycoprotein with an apparent molecular mass of 94 kD (gp94), providing indirect evidence that gp94 is involved in virus adsorption and/or entry into cells. Neutralization of BDV comprises a complex event and, as shown for the first time, involves the carbohydrate residues of both glycoproteins of BDV.

Acetylglucosamine↗
PubMed1997

Distribution and relevance of equine herpesvirus type 2 (EHV-2) infections.

Equine herpesvirus type 2 (EHV-2) is a slow-growing, cytopathogenic gammaherpesvirus, which is suggested to be ubiquitous in the equine population. However, its precise role as a pathogen and its tissue tropism remains uncertain. To estimate the prevalence of EHV-2 in Germany and to investigate the possible pathogenicity of the virus, peripheral blood leucocytes (PBL) from 172 horses were examined for EHV-2 DNA by a sensitive and specific nested PCR based on the EcoRI-N genomic fragment and by classical cocultivation. PBL samples from 51% of the horses were positive by PCR and virus was isolated from 31% of the horses by cocultivation. However, almost all animals were seropositive for EHV-2. This may indicate that PBL do not harbour EHV-2 indefinitely after infection. Furthermore, a correlation between clinical signs and EHV-2 as a causative agent could not be determined. Nevertheless, the prevalence of virus was high among horses with upper respiratory tract disease, abortion and severe ataxia. The products of the second round of the PCR reactions showed size polymorphism. Sequencing of the products revealed that these size differences were due to repetition of the motif (AGACAGGGGCCATGCTGGC) between 9-16 times depending on the isolate, suggesting that the nested PCR might be a useful tool for the differentiation of EHV-2 isolates.

Animals↗
PubMed1997

Equine herpesvirus 4 DNA in trigeminal ganglia of naturally infected horses detected by direct in situ PCR.

Neuronal and lymphoid tissues of 15 randomly selected horses were analysed post mortem by liquid nested-PCR to study the tropism of equine herpesvirus 4 (EHV-4). In four animals the trigeminal ganglia and in one case the lung were positive. Using a direct in situ PCR the EHV-4 genome was localized in the nuclei of neurons and in the bronchiolar as well as alveolar epithelium of the lung. In none of these tissues could infectious virus or viral antigens be detected. Applying the more sensitive liquid RT-PCR, however, an acute infection was demonstrated in one of the trigeminal ganglia by amplification of viral transcripts coding for glycoprotein B. The failure to detect these transcripts in the other trigeminal ganglia and the lung indicates a latent infection. This report formally proves that, like other members of the Alpha-herpesvirinae, EHV-4 establishes latency in the trigeminal ganglia.

Animals↗