Topic:Borna Disease Virus
Borna Disease Virus (BDV) is a neurotropic virus that can infect horses, among other species, leading to neurological disorders. It belongs to the family Bornaviridae and is characterized by its ability to persist in the host's central nervous system. In horses, BDV infection can result in clinical signs such as ataxia, behavioral changes, and other neurological deficits. The virus is primarily transmitted through direct contact or exposure to contaminated environments. Diagnosis of BDV in horses involves the detection of viral RNA or antibodies in biological samples. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, diagnostic methods, and clinical impact of Borna Disease Virus in equine populations.
Clinical, serologic, and histopathologic characterization of experimental Borna disease in ponies. Borna disease was originally described as an equine neurologic syndrome over 200 years ago, although the infectious etiology of the disorder was unproven until the early 20th century. Borna disease virus (BDV) was finally isolated from horses dying of the disorder, and that virus has been used to experimentally reproduce Borna disease in several species of laboratory animals. However, BDV has never been inoculated back into horses to experimentally and etiologically confirm the classic clinical, pathologic, and serologic characteristics of the disease in that species. Three ponies were intrace...
Spontaneous Borna disease in sheep and horses: immunophenotyping of inflammatory cells and detection of MHC-I and MHC-II antigen expression in Borna encephalitis lesions. Borna disease (BD) has been recognized as a virally induced T-cell dependent immunopathological disorder of the central nervous system (CNS), as shown by experimental infection of rats with Borna disease virus (BDV). In contrast to the rat model, little is known about the pathogenesis of spontaneous BD in sheep and horses. The present study describes the brain lesions of 12 ovine and 11 equine cases of naturally occurring BD. A set of monoclonal and polyclonal antibodies was used in order to determine the cells operative in encephalitic lesions and to detect expression of MHC-I and MHC-II prod...
Higher prevalence of Borna disease virus infection in blood donors living near thoroughbred horse farms. It is believed that Borna disease virus (BDV), an etiological agent of progressive polioencephalomyelitis in horses and sheep, is closely associated with psychiatric disorders in humans since the prevalence of BDV is higher in psychiatric patients than in blood donors. We investigated whether or not BDVs in humans are derived from infected domestic animals, by characterizing the BDVs in blood donors and horses derived from the same region of Hokkaido island, Japan. The seroprevalences (2.6 to 14.8%) of BDV were significantly higher in the blood donors from four regions where most horse farms a...
Borna disease virus infection in animals and humans. The geographic distribution and host range of Borna disease (BD), a fatal neurologic disease of horses and sheep, are larger than previously thought. The etiologic agent, Borna disease virus (BDV), has been identified as an enveloped nonsegmented negative-strand RNA virus with unique properties of replication. Data indicate a high degree of genetic stability of BDV in its natural host, the horse. Studies in the Lewis rat have shown that BDV replication does not directly influence vital functions; rather, the disease is caused by a virus-induced T-cell mediated immune reaction. Because antibodi...
[Borna disease virus. An etiological agent in neuropsychiatric diseases?]. Borna disease virus has long been recognized as a cause of sporadic cases and epidemics of meningoencephalomyelitis in horses and sheep in southern parts of Germany. however, sero-epidemiological surveillances indicate that Borna disease virus has a global distribution in horses, without the recognition of clinical manifestations associated with the infection, in other parts of the world. During the past five years evidence has been presented suggesting that humans also can become infected with this virus or a closely related virus. A significantly increased sero-prevalence is seen in patient ...
Demonstration of Borna disease virus (BDV) in specific regions of the brain from horses positive for serum antibodies to BDV but negative for BDV RNA in the blood and internal organs. Sero- and molecular-epidemiological studies on Borna disease virus (BDV) infection show that BDV RNA is not always detected in the peripheral blood mononuclear cells (PBMCs) from serum anti-BDV antibody-positive individuals such as horses, sheep, cattle, cats, and humans. In this study we demonstrated BDV RNA signals by polymerase chain reaction only in restricted regions of the brain from horses with locomotor disease. Four of six horses examined showed apparently positive reactions for anti-BDV antibodies. Specific regions of the brain of these four horses were positive for BDV RNA but the i...
[Immunopathology of Borna disease in the horse: clinical, virological and neuropathologic findings]. Tissues from nine horses and one donkey suffering from natural Borna disease were investigated. Clinically, all animals demonstrated progressive reduced mentation and aggravating gait disturbances. During the clinical course anorexia and progressive loss of proprioception were observed. Cranial nerve failure was accompanied by signs of pharyngeal paralysis, sialorrhea, bruxism, and by blindness. Virologically, infectious virus was detected in the brain of all animals investigated but was not found regularly in all areas of the brain. However, in all cases, infectivity was found in the thalamus...
Varied prevalence of Borna disease virus infection in Arabic, thoroughbred and their cross-bred horses in Iran. Borna disease virus (BDV) naturally infects horses and sheep and induces progressive poliomeningoencephalomyelitis. Here, BDV recombinant proteins of the first open reading frame (ORF-I; coding for p40 nucleoprotein) and the second ORF-II (coding for p24 polymerase cofactor) were immunoblotted with plasma derived from 72 healthy (28 Arabic, 17 thoroughbred and 27 cross-bred) race horses at Tehran in Iran to detect anti-BDV antibodies. In addition, their peripheral blood mononuclear cells (PBMCs) were also examined for BDV RNA by a nested reverse transcriptase-polymerase chain reaction (RT-PCR)...
[Distribution of Borna disease virus in naturally infected animals with clinical disease]. Borna disease (BD) is a naturally occurring enzootic encephalomyelitis of horses and sheep. The aetiological agent, Borna disease virus (BDV) is an unclassified, neurotropic, negative stranded RNA virus. The study aimed at providing further information on BD of naturally infected animals. Samples obtained from 20 animals (18 horses, 1 donkey, 1 sheep) were investigated by a series of virological and molecular biological tests. The highly sensitive reverse transcription-polymerase chain reaction (RT-PCR) method was used to analyze the tissue distribution of BDV-specific RNA. BDV-specific RNA wa...
Sequence variability of Borna disease virus open reading frame II found in human peripheral blood mononuclear cells. A cDNA fragment of the Borna disease virus (BDV) open reading frame II (ORF-II), which encodes a 24-kDa phosphoprotein (p24 [P protein]), was amplified from total RNA of peripheral blood mononuclear cells (PBMC) from three psychiatric inpatients. The amplified cDNA fragments were cloned, sequenced, and analyzed. A total of 15 clones, 5 from each patient, were studied. Intrapatient divergencies of the BDV ORF-II nucleotide sequence were 4.2 to 7.3%, 4.8 to 7.3%, and 2.8 to 7.1% for the three patients, leading to differences of 7.7 to 14.5%, 10.3 to 17.1%, and 6.0 to 16.2%, respectively, in the ...
Demonstration of Borna disease virus RNA in peripheral blood mononuclear cells from healthy horses in Japan. Borna disease (BD) is a progressive poliomeningoencephalomyelitis which occurs naturally in horses and sheep. Here, peripheral blood mononuclear cells (PBMC) derived from 57 healthy horses in Japan were examined by a nested reverse transcription-polymerase chain reaction to determine the prevalence of BD virus (BDV) infection. Seventeen (29.8%) of the samples were positive by this examination and the specificity of the amplified product was confirmed by hybridization with authentic oligomer probes. About 60% of the BDV RNA-positive individuals also showed seropositivity by Western blotting. Th...
Presence of CD4+ and CD8+ T cells and expression of MHC class I and MHC class II antigen in horses with Borna disease virus-induced encephalitis. Tissues from 9 horses and 1 donkey suffering from natural Borna disease were investigated immunomorphologically. Lymphocytic inflammatory reactions and increased expressions of MHC class I and class II antigen were found in the brain as well as in the trigeminal and olfactory system. Perivascular inflammatory infiltrates were dominated by CD4+ T cells, whereas the majority of CD8+ T cells were disseminated intraparenchymally. No evidence of inflammation was found in the retina. Borna disease virus proteins and nucleic acids were present in the hippocampus, thalamus and medulla oblongata in all...
Borna disease–neuropathology and pathogenesis. Natural BD is a nonpurulent acute/subacute encephalitis of horses and sheep with a propensity to involve the olfactory and limbic systems, and the brain stem. The inflammation is concentrated primarily in the gray matter, but subcortical white matter may also be affected. Experimental BD can be produced in a series of animals from birds to primates. The neuropathology after experimental infection is similar to that in natural disease but the inflammatory changes are more diffuse. In the rat and mouse, a persistent/tolerant infection can also be induced, in which inflammatory changes are conspi...
Sequence analyses of the p24 gene of Borna disease virus in naturally infected horse, donkey and sheep. By reverse transcriptase/PCR amplification and subsequent sequence determination of the p24 gene, the relatedness of Borna disease virus (BDV) in various naturally infected animal species was determined. These results are indicative of a common ancestral virus pool and a remarkably low species barrier of BDV. Comparison of 11 sequences to that of tissue culture adapted virus revealed that the homology among all isolates was at least 96.2% at the nucleotide level, and 97% at the amino acid level. Viral sequences from sheep, donkey and horse were found to be not more distantly related to each ot...
Detection of Borna disease virus RNA in naturally infected animals by a nested polymerase chain reaction. Borna disease virus in naturally infected horses, a donkey and sheep was detected for the first time by amplification of viral RNA using PCR. In contrast to a control group of healthy horses, brain tissue was positive by this assay in all animals with neurological symptoms. The use of a second round of PCR with nested primers following Southern hybridization confirmed the specificity and increased the sensitivity of the test. Comparison with conventional methods recommends this technique for monitoring of BDV infections at a molecular level.
Detection of antibodies against Borna disease virus in sera and cerebrospinal fluid of horses in the USA. Sera from 295 horses in the USA were examined by an indirect immunofluorescence assay and Western blot assays to determine the prevalence of Borna disease virus infection. Eight (2.7 per cent) of the samples were positive in both assays, and 18 (6.1 per cent) were positive only in the Western blot assay. The indirect fluorescence titres ranged from 1:20 to 1:80 of antibodies recognising the virus-specific antigen from Borna disease virus-infected cells. The purified virus-specific proteins isolated from infected rat brains were recognised by positive equine serum samples after immunostaining b...
Biology and neurobiology of Borna disease viruses (BDV), defined by antibodies, neutralizability and their pathogenic potential. Borna disease viruses (BDV) isolated from more than 20 naturally infected horses, 2 sheep and a possible feline isolate were included in these studies. Most of these wild-type viruses were grown in rabbit cells. Specifically rabbit-adapted viruses establish persistent infection in immortalized cell lines of various animal species. Brain-, tissue culture-, and cell-free released viruses could all be neutralized with antibodies from naturally and experimentally infected animals (horse; hamster, rat, rabbit, mouse, and chicken), with highest titres in birds. Splenectomized rabbits, which were sub...
Pathogenesis of Borna disease. Borna disease represents a unique model of a virus-induced immunological disease of the brain. Naturally occurring in horses and sheep, the mechanisms of pathogenesis have been studied in experimental animals, namely in the rat. Many investigations have revealed that the infection of the natural hosts principally follows the same pathogenic pathways as observed in rats, leading to a severe encephalomyelitis. This affliction of the central nervous system results in severe neurological disorders that again, are fully comparable in laboratory animals to those in the natural and the different expe...
[Immunopathogenesis of Borna disease]. An overview of the pathogenesis of Borna disease (BD) in rats as a model for the naturally occurring infection in horses and sheep is presented. Our findings revealed a virus infection in which a virus-specific T cell-mediated immune response leads to disease. The immune cells capable of mediating this immunopathological reaction were defined as helper/inducer T cells. In all, the described observations indicate that CD4+ T cells and macrophages trigger a delayed-type hypersensitivity reaction and cause BD together with other cells of the immune system.
[Symptomatology and diagnosis of Borna encephalitis of horses. A case analysis of the last 13 years]. In a retrospective study of 38 horses with Borna encephalitis which were clinically and histopathologically examined in the "I. Medizinische Tierklinik" in Munich between 1977 and 1990, the epidemiology, the clinical symptomatic and the diagnostic procedures available are presented. Indirect immunofluorescence showed antibodies in the serum of 12 out of 29 cases (41%) and in the cerebrospinal fluid (CSF) of 17 out of 28 cases (61%). The evaluation of 23 cases in which indirect immunofluorescence of serum and CSF, and also the post mortem virological and histopathological examination of the bra...
Immune-mediated pathogenesis of Borna disease. Borna disease is an endemic progressive encephalomyelitis of horses and sheep prevalent in central Europe. A wide variety of animal species, ranging from chickens to primates can be infected experimentally with the causative virus, which is only poorly characterized. Furthermore, BD virus-specific antibodies have been detected in sera and cerebrospinal fluids of psychiatric patients. Our studies on the pathogenesis of BD have shown that-at least in rats-the disease is not caused by the infecting virus itself, but by a virus-induced immunopathological reaction. Thus, after intracerebral infecti...
Borna disease of horses. An immunohistological and virological study of naturally infected animals. The brains of eight horses that had suffered from natural Borna disease were examined with virologic, immunohistological, and electron-microscopic methods. All brains harbored infectious virus as shown by inoculation of experimental animals. Regional assessment of the infectivity exhibited the highest titers in the hippocampus and piriform cortex and the lowest in the cerebellum. Conventional histology yielded pathologic alterations very similar to those of the classical description of the disease. Immunohistology demonstrated the highest amounts of Borna disease virus-specific antigen in the ...
Demonstration of specific antibodies in the central nervous system of horses naturally infected with Borna disease virus. From 18 horses with clinical symptoms of an affection of the central nervous system and with histopathologic alterations in the brain, four were demonstrated to have Bornavirus-specific antibodies. The antibodies are monospecific, recognizing identical antigens from infected brains of different animal species as well as from persistently infected tissue culture cells. Discrete immunoglobulin species (oligoclonal IgG) can be demonstrated in concentrated horse cerebrospinal fluid; they carry Bornavirus antibody specificity. Their presence, together with the higher antibody titers in the cerebros...