Herpes B Research Articles

Identifying Sites Bound by Epstein-Barr Virus Nuclear Antigen 1 (EBNA1) in the Human Genome: Defining a Position-Weighted Matrix To Predict Sites Bound by EBNA1 in Viral Genomes

We identified binding sites for Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) in the human genome using chromatin immunoprecipitation and microarrays. The sequences for these newly identified sites were used to generate a position-weighted matrix (PWM) for EBNA1's DNA-binding sites. This PWM helped identify additional DNA-binding sites for EBNA1 in the genomes of EBV, Kaposi's sarcoma-associated herpesvirus, and cercopithecine herpesvirus 15 (CeHV-15) (also called herpesvirus papio 15). In particular, a homologue of the Rep* locus in EBV was predicted in the genome of CeHV-15, which is notable because Rep* of EBV was not predicted by the previously developed consensus sequence for EBNA1's binding DNA. The Rep* of CeHV-15 functions as an origin of DNA synthesis in the EBV-positive cell line Raji; this finding thus builds on a set of DNA-binding sites for EBNA1 predicted in silico.

Hepatitis B virus infection in non-human primates

Hepatitis B viruses (HBVs) represent a serious public health problem affecting 350 to 400 million HBV carriers worldwide. The virus does not exclusively infect humans, but can also be found in non-human primates as in the families Hominidae (chimpanzee, gorilla, orangutan) and Hylobatidae (gibbon), which are distributed over Africa (chimpanzee and gorilla) and Southeast Asia (orangutan and gibbon), the endemic areas of human HBV. The prevalence of asymptomatic HBV carriers reaches in gibbons 23-33% and in orangutans 15%. The genome organization of non-human primate HBVs is nearly identical to that of human HBVs. Because of this close similarity, the question of cross-transmission of HBV between species has arisen. There are many data on cross-transmission of human HBVs to the non-human primates. However, a cross-transmission of HBVs from non-human primates to humans has not been reported yet. Using more advanced diagnostic methods, the non-human primates have increasingly been identified as a reservoir of several viruses such as lymphocryptoviruses, Cercopithecine herpesvirus 1 (CeHV-1), Simian immunodeficiency virus (SIV), Simian foamy virus (SFV), and HBVs. Thus veterinarians, zookeepers, or people in close contact with non-human primates may potentially become infected with those viruses causing severe diseases. Enhanced awareness of prevalence, genetic relatedness and evolution of non-human primate HBVs will help prevent further spread and cross-transmission of these viruses between humans and non-human primates.

Recommendation for post-exposure prophylaxis after potential exposure to herpes b virus in Germany

Although the risk of a herpes B virus (Cercopithecine herpes virus 1) infection is low, the clinical course of the infectious disease is generally unfavourable. A high safety standard can be achieved if people with professional contact to primates apply proper organisational, technical and personal safety precautions. The risk can be considerably reduced if animal keepers, laboratory assistants and scientists receive adequate information about the pathology of herpes B virus and are well trained in the necessary procedures and the precautions. For this reason, comprehensive and regular training, information and instruction must be provided to all primate workers and to laboratory workers who come into contact with potentially infectious material. After potential contamination, the risk for the affected worker must be assessed immediately and post-exposure chemoprophylaxis performed if necessary. This necessitates internal risk assessment. An interdisciplinary group of experts has developed an action plan for Germany.

An in‐silico study of alphaherpesviruses ICP0 genes: Positive selection or strong mutational GC‐pressure?

The purpose of our work was to analyze the case of the strong mutational GC-pressure influence on the ratio between nonsynonymous (DN) and synonymous (DS) distances (DN/DS ratio). We have used as the material the genes coding for ICP0 from five completely sequenced genomes of simplexviruses. DN/DS ratio, total GC-content (G + C), and GC-content in first, second, and third codon positions (1GC, 2GC, and 3GC, respectively) have been calculated separately for exon 2, nonconserved part of exon 3, and conserved part of exon 3 from ICP0 genes. Results showed that DN is more than DS only in the conserved part of exon 3 of ICP0 genes from cercopithecine herpesvirus 2 and cercopithecine herpesvirus 16. However, the cause of this result (DN/DS = 2.54) is the GC-pressure acting on the coding districts with 3GC = 99% rather than the biological process called positive selection. Only in these two viruses, because of the strong GC-pressure, 3GC has reached 99% in the conserved part of ICP0 exon 3, and so nucleotide substitutions that increase the GC-content practically cannot occur in third codon positions, where most substitutions are synonymous. In this case, GC-pressure has a substrate for nucleotide substitutions only in first and second codon positions, where most substitutions are nonsynonymous.

Infection humaine par le virus B du singe en Afrique

Simian herpes B virus or Cercopithecine herpesvirus 1 (CeHV-1) is enzootic (80% to 100%) in Asian monkeys of the genus Macaca but is also present in other monkey species. This virus, discovered in 1933, is closely related to human herpesvirus 1 and human herpesvirus 2, responsible respectively for labial and genital herpes. CeHV-1 infection is generally asymptomatic or mild in monkeys but in humans it may lead to fulminant encephalomyelitis that has an 80% lethality rate without treatment. Infections in humans are usually attributed to animal bites or scratches or to percutaneous or mucosal inoculation with infected materials from asymptomatic monkeys. Although the incidence of human infection with CeHV-1 is low, until the availability of antiviral therapy its death rate made this virus a serious zoonotic threat. Even now, good knowledge of its clinical signs and risk factors is essential for only they allow early and swift antiviral therapy (acyclovir, valacyclovir, or famciclovir) and prevent severe disease or fatal outcome. This article describes the virus, the resulting disease in human and a suspected clinical case involving a woman bit by a vervet monkey (Cercopithecus aethiops) in Garamba National Park in the Democratic Republic of the Congo.

Specific Pathogen-Free Macaques: Definition, History, and Current Production

Specific pathogen-free (SPF) macaque colonies are now requested frequently as a resource for research. Such colonies were originally conceived as a means to cull diseased animals from research-dedicated colonies, with the goal of eliminating debilitating or fatal infectious agents from the colony to improve the reproductive capacity of captive research animals. The initial pathogen of concern was Mycobacterium tuberculosis (M.tb.), recognized for many years as a pathogen of nonhuman primates as well as a human health target. More recently attention has focused on four viral pathogens as the basis for an SPF colony: simian type D retrovirus (SRV), simian immunodeficiency virus (SIV), simian T cell lymphotropic/leukemia virus (STLV), and Cercopithecine herpesvirus 1 (CHV-1). New technologies, breeding, and maintenance schemes have emerged to develop and provide SPF primates for research. In this review we focus on the nonhuman primates (NHPs) most common to North American NHP research facilities, Asian macaques, and the most common current research application of these animals, modeling of human AIDS.

Sensitivity of monkey B virus (Cercopithecine herpesvirus 1) to antiviral drugs: role of thymidine kinase in antiviral activities of substrate analogs and acyclonucleosides.

Herpes B virus (B virus [BV]) is a macaque herpesvirus that is occasionally transmitted to humans where it can cause rapidly ascending encephalitis that is often fatal. To understand the low susceptibility of BV to the acyclonucleosides, we have cloned, expressed, and characterized the BV thymidine kinase (TK), an enzyme that is expected to "activate" nucleoside analogs. This enzyme is similar in sequence and properties to the TK of herpes simplex virus (HSV), i.e., it has a broad substrate range and low enantioselectivity and is sensitive to inhibitors of HSV TKs. The BV enzyme phosphorylates some modified nucleosides and acyclonucleosides and l enantiomers of thymidine and related antiherpetic analogs. However, the potent anti-HSV drugs acyclovir (ACV), ganciclovir (GCV), and 5-bromovinyldeoxyuridine were poorly or not phosphorylated by the BV enzyme under the experimental conditions. The antiviral activities of a number of marketed antiherpes drugs and experimental compounds were compared against BV strains and, for comparison, HSV type 1 (HSV-1) in Vero cell cultures. For most compounds tested, BV was found to be about as sensitive as HSV-1 was. However, BV was less sensitive to ACV and GCV than HSV-1 was. The abilities of thymidine analogs and acyclonucleosides to inhibit replication of BV in Vero cell culture were not always proportional to their substrate properties for BV TK. Our studies characterize BV TK for the first time and suggest new lead compounds, e.g., 5-ethyldeoxyuridine and pencyclovir, which may be superior to ACV or GCV as treatment for this emerging infectious disease.

Prevalence of antibody reaction with cercopithecine herpesvirus 1 antigen in Macaca cyclopis, Macaca fascicularis, and Papio anubis in Taiwan

A total of 284 non-human primate sera were collected between December 2004 and September 2005 and tested by a commercially available dot immunobinding assay for the antibodies to cercopithecine herpesvirus 1, an alphaherpesvirus with high mortality for infected humans. Seropositive rates were 58% among non-human primates from animal shelters and 38% among those from zoos and academic institutes. Positive reactors were found in three species, the Formosan macaque (Macaca cyclopis; 57%), the cynomolgus macaque (Macaca fascicularis; 11%) and the olive baboon (Papio anubis; 68%). Our results showed that natural infection by cercopithecine herpesvirus 1 in Formosan macaques was highly prevalent, and to a certain extent reflected the situation of the wild populations in Taiwan. The findings raised the issues of zoonotic public health and the occupational health of primate workers. High positive rate in olive baboons was also found, although, it cannot be ruled out that the positivity was due to cross-reactivity between cercopithecine herpesvirus 1 and other herpesviruses.

Differential distribution of antibodies to different viruses in young animals in the free‐ranging rhesus macaques of Cayo Santiago

The breeding colony of free-ranging rhesus macaques was established in 1938 in Cayo Santiago (CS) with animals collected in northern India. The seroprevalence to cercopithecine herpesvirus type 1 (B virus) and simian retroviruses has been studied previously. This is the first report on the seropositivity to different viruses using samples collected shortly after removing animals (n = 245) from CS. All samples were negative for measles, simian immunodeficiency virus and simian type D retroviruses. The overall prevalence of antibodies was around 50% for simian T-lymphotropic virus I (STLV-I). For B virus, the prevalence was 38%. Data obtained showed marked differences in the antibody distribution to B virus and STLV-I within the free-ranging colony of rhesus macaques. Implication of these data for the Specific Pathogen Free program at the Caribbean Primate Research Center are also discussed.

Temple Monkeys and Health Implications of Commensalism, Kathmandu, Nepal

The threat of zoonotic transmission of infectious agents at monkey temples highlights the necessity of investigating the prevalence of enzootic infectious agents in these primate populations. Biological samples were collected from 39 rhesus macaques at the Swoyambhu Temple and tested by enzyme-linked immunosorbent assay, Western blot, polymerase chain reaction, or combination of these tests for evidence of infection with rhesus cytomegalovirus (RhCMV), Cercopithecine herpesvirus 1 (CHV-1), simian virus 40 (SV40), simian retrovirus (SRV), simian T-cell lymphotropic virus (STLV), simian immunodeficiency virus (SIV), and simian foamy virus (SFV). Antibody seroprevalence was 94.9% to RhCMV (37/39), 89.7% to SV40 (35/39), 64.1% to CHV-1 (25/39), and 97.4% to SFV (38/39). Humans who come into contact with macaques at Swoyambhu risk exposure to enzootic primateborne viruses. We discuss implications for public health and primate management strategies that would reduce contact between humans and primates.

Neuropathogenesis of herpesvirus papio 2 in mice parallels infection with Cercopithecine herpesvirus 1 (B virus) in humans

Cercopithecine herpesvirus 1 (monkey B virus; BV) produces extremely severe and usually fatal infections when transmitted from macaque monkeys to humans. Cercopithecine herpesvirus 16 (herpesvirus papio 2; HVP2) is very closely related to BV, yet cases of human HVP2 infection are unknown. However, following intramuscular inoculation of mice, HVP2 rapidly invades the peripheral nervous system and ascends the central nervous system (CNS) resulting in death, very much like human BV infections. In this study, the neurovirulence of HVP2 in mice was further evaluated as a potential model system for human BV infections. HVP2 was consistently neurovirulent when administered by epidermal scarification, intracranial inoculation and an eye splash. Quantitative real-time PCR, histopathology and immunohistochemistry were used to follow the temporal spread of virus following skin scarification and to compare the pathogenesis of neurovirulent and apathogenic isolates of HVP2. Apathogenic isolates were found to be capable of reaching the CNS but were extremely inefficient at replicating within the CNS. It is concluded that neurovirulent strains of HVP2 exhibit a pathogenesis in mice that parallels that observed in human BV infections and that this model system may prove useful in dissecting the viral determinants underlying the extreme severity of zoonotic BV infections.

The Complete Genome Sequence of Herpesvirus Papio 2 ( Cercopithecine Herpesvirus 16 ) Shows Evidence of Recombination Events among Various Progenitor Herpesviruses

We have sequenced the entire genome of herpesvirus papio 2 (HVP-2; Cercopithecine herpesvirus 16) strain X313, a baboon herpesvirus with close homology to other primate alphaherpesviruses, such as SA8, monkey B virus, and herpes simplex virus (HSV) type 1 and type 2. The genome of HVP-2 is 156,487 bp in length, with an overall GC content of 76.5%. The genome organization is identical to that of the other members of the genus Simplexvirus, with a long and a short unique region, each bordered by inverted repeats which end with an "a" sequence. All of the open reading frames detected in this genome were homologous and colinear with those of SA8 and B virus. The HSV gene RL1 (gamma(1)34.5; neurovirulence factor) is not present in HVP-2, as is the case for SA8 and B virus. The HVP-2 genome is 85% homologous to its closest relative, SA8. However, segment-by-segment bootstrap analysis of the genome revealed at least two regions that display closer homology to the corresponding sequences of B virus. The first region comprises the UL41 to UL44 genes, and the second region is located within the UL36 gene. We hypothesize that this localized and defined shift in homology is due to recombination events between an SA8-like progenitor of HVP-2 and a herpesvirus species more closely related to the B virus. Since some of the genes involved in these putative recombination events are determinants of virulence, a comparative analysis of their function may provide insight into the pathogenic mechanism of simplexviruses.

Prevalence of enzootic simian viruses among urban performance monkeys in Indonesia

Animal reservoirs are the most important sources of emerging infectious diseases that threaten human populations. Global travel and tourism bring ever-increasing numbers of humans into contact with animals, increasing the likelihood of cross species transmission of infectious agents. Non-human primates come into contact with humans in a variety of contexts and may harbor infectious agents with zoonotic potential. We investigated the prevalence of infection with enzootic simian viruses among 20 urban performance monkeys (Macaca fascicularis) in Jakarta, Indonesia. This report documents for the first time evidence of infection with four simian viruses in urban performance monkeys. Simian foamy virus was detected by PCR in 52.9% of the macaques. Antibodies to simian retrovirus were detected in 10.5% of the macaques. Antibodies to Cercopithecine Herpesvirus 1, were detected in 5.3% of the macaques. Similarly, antibodies to simian T-cell lymphotropic virus were detected in 5.3% of the macaques. No evidence of infection with simian immunodeficiency virus was detected in these macaques. These results suggest that urban performance monkeys are a reservoir for enzootic simian viruses known to be capable of infecting humans.

DNA polymerase gene locus of Cercopithecine herpesvirus 1 is a suitable target for specific and rapid identification of viral infection by PCR technology

The family Herpesviridae comprises at least 100 herpesviruses. Numerous human and animal pathogenic herpesviruses have been identified so far, including Cercopithecine herpesvirus 1 (CeHV-1). This virus is a member of the subfamily Alphaherpesvirinae and is the most hazardous herpesvirus to man. CeHV-1 is also known as B-virus or monkey B virus and as Herpesvirus simiae. In order to gain more genetic information, the viral DNA polymerase (DPOL) gene was identified using polymerase chain reaction (PCR) and DNA nucleotide sequence analysis. The deduced amino acid sequence contains the motifs and signatures that are typical for the B-family of DPOLs. The DPOL gene of CeHV-1 was found to be a suitable target for the specific and rapid identification of the Cercopithecine herpesvirus 1 infection by PCR technology. Comparative analysis of the DNA sequences of the DPOL gene loci of CeHV-1, Human herpesvirus 1 and 2 (HHV-1 and HHV-2), and other herpesviruses was carried out for determination of unique genomic regions of the individual DPOL genes. A primer set of 12 primers was used for screening the DNA of CeHV-1, HHV-1, and HHV-2 by detailed PCR. It was found that six out of twelve primer combinations are able to detect specifically the CeHV-1 genome without cross reactivity with the genome of HHV-1 and/or HHV-2. The specificity of the individual amplified DNA fragments was confirmed by DNA nucleotide sequence analysis. The results of these studies indicate that the six primer combinations of the specific CeHV-1 DPOL primer set is the method of choice for a rapid, precise and specific identification of a CeHV-1 infection by PCR. Due to the fact that this specific CeHV-1 DPOL primer set does not amplify any DNAs of HHV-1 or HHV-2 genome this technology is stressing and can be successfully used unlimited and more credible in all laboratories with PCR technical facility routinely for detection of a CeHV-1 infection in vivo or in vitro.

Production of Herpes B Virus Recombinant Glycoproteins and Evaluation of Their Diagnostic Potential

B virus (cercopithecine herpesvirus 1) is the only deadly alphaherpesvirus that is zoonotically transmissible from macaques to humans. The detection of humoral immune responses is the method of choice for the rapid identification of B virus-infected animals. We evaluated the diagnostic potential of recombinant B virus glycoproteins for the detection of immunoglobulin G (IgG) antibodies in monkey and human sera. Glycoproteins B, C, and E and secreted (sgG) and membrane-associated (mgG) segments of glycoprotein G (gG) were expressed in the baculovirus expression system, while gD was expressed in CHO cells. We developed recombinant protein-based IgG enzyme-linked immunosorbent assays (ELISAs) and compared their diagnostic efficacies by using B virus antibody-negative (n = 40) and -positive (n = 75) macaque sera identified by a whole antigen-based ELISA and Western blotting. The diagnostic sensitivities of the gB-, gC-, gD-, and mgG-ELISAs were 100, 97.3, 88.0, and 80.0%, respectively. The specificities of the gB-, gC-, and gD-ELISAs and of the mgG-ELISA were 100 and 97.5%, respectively. In contrast, the sensitivities and specificities of sgG- and gE-ELISAs were low, suggesting that sgG and gE are less effective diagnostic antigens. Sera from nonmacaque monkeys cross-reacted with gB, gC, and gD, and only baboon sera reacted weakly with mgG. Human herpes simplex virus type 1 (HSV-1)- and HSV-2-positive sera pools reacted with gB and gD, whereas sera from B virus-infected individuals reacted with all four antigens. These data indicate that gB, gC, gD, and mgG have a high diagnostic potential for B virus serodiagnosis in macaques, whereas mgG may be a valuable antigen for discrimination between antibodies induced by B virus and those induced by other, closely related alphaherpesviruses, including HSV-1 and -2.

Complete genome sequence of cercopithecine herpesvirus 2 (SA8) and comparison with other simplexviruses

We have obtained the complete sequence of the herpesvirus simian agent 8 (SA8; cercopithecine herpesvirus 2) a baboon simplexvirus closely related to the monkey B virus and herpes simplex virus types 1 and 2. The genome of SA8 is 150,715 bp long, with an overall G/C content of 76%, the highest among the simplexviruses sequenced so far. The sequencing has confirmed that the genomic arrangement of SA8 is similar to that of other simplexviruses: unique long and unique short regions bordered by two sets of inverted repeats. All genes identified in SA8 are homologous and collinear with those of the monkey B virus, including the lack of the RL1 open reading frame, a gene responsible for neurovirulence in human herpes simplex viruses. This latter finding supports the hypothesis that a different pathogenetic mechanism may have developed in human simplexviruses, after their divergence from monkey simplexviruses.

Recommendations for Prevention of and Therapy for Exposure to B virus (Cercopithecine Herpesvirus 1)

Recommendations for Prevention of and Therapy for Exposure to B virus (Cercopithecine Herpesvirus 1)

Cloning and expression of the complement receptor glycoprotein C from Herpesvirus simiae (herpes B virus): protection from complement-mediated cell lysis.

Simian herpes B virus (SHBV) is the herpes simplex virus (HSV) homologue for the species MACACA: Unlike in its natural host, and unlike other animal herpesviruses, SHBV causes high mortality in accidentally infected humans. SHBV-infected cells, like those infected with HSV-1 and equine herpesvirus types 1 and 4, express complement C3 receptor activity. To study immunoregulatory functions involved in susceptibility/resistance against interspecies transmission, the SHBV glycoprotein C (gC(SHBV)) gene (encoding 467 aa) was isolated. Sequence analysis revealed amino acid identity with gC proteins from HSV-2 (46.9 %), HSV-1 (44.5 %) and pseudorabies virus (21.2 %). Highly conserved cysteine residues were also noted. Similar to gC(HSV-2), gC(SHBV) is less glycosylated than gC(HSV-1), resulting in a molecular mass of 65 kDa if expressed in replication-deficient vaccinia virus Ankara. Stable transfectants expressing full-length gC(SHBV) on the cell surface induced C3 receptor activity and were substantially protected from complement-mediated lysis; no protection was observed with control constructs. This suggests that expression of the gC homologues on infected cell surfaces might also contribute to the survival of infected cells in addition to decreased virion inactivation. Interestingly, soluble gC(SHBV) isolated from protein-free culture supernatants did not interfere with the binding of the alternative complement pathway activator properdin to C3b, which is similar to our findings with gC(HSV-2) and could be attributed to major differences in the amino-terminal portion of the protein with extended deletions in both gC(SHBV) and gC(HSV-2). Binding of recombinant gC(SHBV) to polysulphates was observed. This, together with the heparin-sensitivity of the gC(SHBV)-C3 interaction on the infected cell surface, suggests a role in adherence to heparan sulphate, similar to the gC proteins of other herpesviruses.

Quantitative real-time PCR for detection of monkey B virus ( Cercopithecine herpesvirus 1) in clinical samples

A TaqMan based real-time PCR assay was developed for rapid detection and quantitation of herpes B virus ( Cercopithecine herpesvirus 1) in clinical samples. The assay utilizes B virus-specific primers and a probe to the non-conserved region of the gG gene to discriminate B virus from closely related alphaherpesviruses. Fifty copies of B virus DNA could be detected with 100% sensitivity with a wide range of quantitation spanning 6 logs. The assay was highly reproducible with intra- and inter-assay coefficients of variation of 0.6 and 2.4%, respectively. Clinical utility of the developed real-time PCR was evaluated by testing genomic DNA prepared from B virus clinical isolates ( n=23) and human and monkey clinical specimens ( n=62). This novel method was also compared with conventional cell culture with respect to sensitivity and specificity. TaqMan PCR assay was shown to be equally specific and more sensitive than culture method (culture vs. PCR sensitivity 50%) and was able to identify all B virus clinical isolates tested. Fast, reliable assessment of B virus DNA in infected cells and tissues makes real-time PCR assay a valuable tool for diagnosis and management of B virus infections.

Detection and species-level identification of primate herpesviruses with a comprehensive PCR test for human herpesviruses.

A comprehensive assay for the identification of all eight human herpesviruses has been previously reported. This assay was extended to the detection and species-level identification of herpes B virus (Cercopithecine herpesvirus 1) and African green monkey cytomegalovirus (Cercopithecine herpesvirus 5), two herpesviruses of relevance to the clinical virology laboratory.