Animal Models of Alzheimer's Disease Should Be Controlled for Roseolovirus.

Animal models to study Alzheimer's disease (AD) pathogenesis are under development. Since herpesviruses have been postulated to be capable of triggering the pathogenic process, AD animal models (mouse, pig, and non-human primates) should be controlled for the presence of these viruses. Only virus-free models allow studying the genetic factors and the effect of adding viruses. Roseoloviruses such as human herpesvirus 6 and the related viruses in the animals are the main topic of this commentary.

Past, present, and future perspectives on the diagnosis of Roseolovirus infections.

Diagnosis of Roseolovirus infections mandates careful selection of patients, samples, and testing methods. We review advances in the field and highlight research priorities. Quantitative (q)PCR can accurately identify and distinguish between human herpesvirus 6 (HHV-6) species A and B. Whether screening of high-risk patients improves outcomes is unclear. Chromosomally integrated (ci)HHV-6 confounds test interpretation but can be ruled out with digital PCR. Reverse transcription qPCR may be a more specific and clinically applicable test for actively replicating Roseoloviruses, particularly among patients with ciHHV-6. Interpretation of Roseolovirus test results faces many challenges. However, careful application of refined and emerging diagnostic techniques will allow for increasingly accurate diagnosis of clinically significant infections and disease associations.

African great apes are naturally infected with roseoloviruses closely related to human herpesvirus 7.

UNLABELLED: Primates are naturally infected with herpesviruses. During the last 15 years, the search for homologues of human herpesviruses in nonhuman primates allowed the identification of numerous viruses belonging to the different herpesvirus subfamilies and genera. No simian homologue of human herpesvirus 7 (HHV7) has been reported to date. To investigate the putative existence of HHV7-like viruses in African great apes, we applied the consensus-degenerate hybrid oligonucleotide primers (CODEHOP) program-mediated PCR strategy to blood DNA samples from the four common chimpanzee subspecies (Pan troglodytes verus, P. t. ellioti, P. t. troglodytes, and P. t. schweinfurthii), pygmy chimpanzees (Pan paniscus), as well as lowland gorillas (Gorilla gorilla gorilla). This study led to the discovery of a novel roseolovirus close to HHV7 in each of these nonhuman primate species and subspecies. Generation of the partial glycoprotein B (1,111-bp) and full-length DNA polymerase (3,036/3,042-bp) gene sequences allowed the deciphering of their evolutionary relationships. Phylogenetic analyses revealed that HHV7 and its African great ape homologues formed well-supported monophyletic lineages whose topological resemblance to the host phylogeny is suggestive of virus-host codivergence. Notably, the evolutionary branching points that separate HHV7 from African great ape herpesvirus 7 are remarkably congruent with the dates of divergence of their hosts. Our study shows that African great apes are hosts of human herpesvirus homologues, including HHV7 homologues, and that the latter, like other DNA viruses that establish persistent infections, have cospeciated with their hosts. IMPORTANCE: Human herpesviruses are known to possess simian homologues. However, surprisingly, none has been identified to date for human herpesvirus 7 (HHV7). This study is the first to describe simian homologues of HHV7. The extensive search performed on almost all African great ape species and subspecies, i.e., common chimpanzees of the four subspecies, bonobos, and lowland gorillas, has allowed characterization of a specific virus in each. Genetic characterization of the partial glycoprotein B and full-length DNA polymerase gene sequences, followed by their phylogenetic analysis and estimation of divergence times, has shed light on the evolutionary relationships of these viruses. In this respect, we conclusively demonstrate the cospeciation between these new viruses and their hosts and report cases of cross-species transmission between two common chimpanzee subspecies in both directions.

Detection of viral pathogens in high grade gliomas from unmapped next-generation sequencing data.

Viral pathogens have been implicated in the development of certain cancers including human papillomavirus (HPV) in squamous cell carcinoma and Epstein-Barr virus (EBV) in Burkitt's lymphoma. The significance of viral pathogens in brain tumors is controversial, and human cytomegalovirus (HCMV) has been associated with glioblastoma (GBM) in some but not all studies, making the role of HCMV unclear. In this study we sought to determine if viral pathogen sequences could be identified in an unbiased manner from previously discarded, unmapped, non-human, next-generation sequencing (NGS) reads obtained from targeted oncology, panel-based sequencing of high grade gliomas (HGGs), including GBMs. Twenty one sequential HGG cases were analyzed by a targeted NGS clinical oncology panel containing 151 genes using DNA obtained from formalin-fixed, paraffin-embedded (FFPE) tissue. Sequencing reads that did not map to the human genome (average of 38,000 non-human reads/case (1.9%)) were filtered and low quality reads removed. Extracted high quality reads were then sequentially aligned to the National Center for Biotechnology Information (NCBI) non-redundant nucleotide (nt and nr) databases. Aligned reads were classified based on NCBI taxonomy database and all eukaryotic viral sequences were further classified into viral families. Two viral sequences (both herpesviruses), EBV and Roseolovirus were detected in 5/21 (24%) cases and in 1/21 (5%) cases, respectively. None of the cases had detectable HCMV. Of the five HGG cases with detectable EBV DNA, four had additional material for EBV in situ hybridization (ISH), all of which were negative for expressed viral sequence. Overall, a similar discovery approach using unmapped non-human NGS reads could be used to discover viral sequences in other cancer types.

Molecular and biological characterization of a new isolate of guinea pig cytomegalovirus.

Development of a vaccine against congenital infection with human cytomegalovirus is complicated by the issue of re-infection, with subsequent vertical transmission, in women with pre-conception immunity to the virus. The study of experimental therapeutic prevention of re-infection would ideally be undertaken in a small animal model, such as the guinea pig cytomegalovirus (GPCMV) model, prior to human clinical trials. However, the ability to model re-infection in the GPCMV model has been limited by availability of only one strain of virus, the 22122 strain, isolated in 1957. In this report, we describe the isolation of a new GPCMV strain, the CIDMTR strain. This strain demonstrated morphological characteristics of a typical Herpesvirinae by electron microscopy. Illumina and PacBio sequencing demonstrated a genome of 232,778 nt. Novel open reading frames ORFs not found in reference strain 22122 included an additional MHC Class I homolog near the right genome terminus. The CIDMTR strain was capable of dissemination in immune compromised guinea pigs, and was found to be capable of congenital transmission in GPCMV-immune dams previously infected with salivary gland­adapted strain 22122 virus. The availability of a new GPCMV strain should facilitate study of re-infection in this small animal model.

Detection of five rash-associated viruses using multiplex real-time PCR during 2006-2011.

Many viruses have been reported to be associated with rash development. Multiplex real-time PCR was used to investigate the presence of 5 viruses associated with rashes: measles virus (MV), rubella virus (RV), human parvovirus B19 (PVB19), human herpes virus 6 (HHV-6), and HHV-7. A total of 187 clinical specimens from 169 patients with erythema were collected between January 2006 and December 2011. Virus-positive specimens were as follows: MV (n = 23), PVB19 (n = 8), RV (n = 2), HHV-6 (n = 5), HHV-7 (n = 1), MV and PVB19 (n = 1), and HHV-6 and HHV-7 (n = 1). All of the MV-positive specimens were collected in 2007 and the strains whose sequence were available (21/24, 87.5%) were of genotype D5. The results indicate that multiplex real-time PCR might be a useful screening method for detecting and differentiating rash-associated viruses in clinical specimens.

Identification of human herpesviruses 1 to 8 in Tunisian multiple sclerosis patients and healthy blood donors.

Members of the human Herpesviridae family are candidates for representing the macroenvironmental factors associated with multiple sclerosis (MS) pathogenesis. To verify the possible role of human herpesviruses (HHVs) as triggering or aggravating factors in relapsing-remitting multiple sclerosis clinical outcome, we studied the prevalence of all eight human herpesviruses in whole blood samples collected from 51 MS patients and from 51 healthy controls. The presence of DNA of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus 6 (HHV-6), human herpesvirus 7 (HHV-7) and human herpesvirus 8 (HHV-8) was searched by specific nested polymerase chain reaction. HHVs were significantly more prevalent in the blood of MS patients than in those of the controls (P < 10(-4)). HSV-1, HSV-2, HCMV and HHV-8 were negative in both MS patients and controls samples. In MS patients, EBV, HHV-7, HHV-6 and VZV were detected in 31.3%, 33.3%, 5.8% and 7.8% of samples, respectively, compared with 3.9%, 9.8%, 1.96% and 1.96%, respectively, of samples from controls. We found a statistically significant difference only for EBV DNA and for HHV-7 DNA prevalence (P < 0.001 and P = 0.03). Although these results indicate lack of apparent association in terms of gender, type of diagnosis, symptoms, disease score and ß interferon treatment between EBV or HHV-7 to MS among Tunisian patients, heterogeneity related to genetic polymorphism as well as geographical distribution of the disease and of pathogens may be of significance.

[Is antiviral therapy in gastroduodenal pathology necessary?].

Mucous membrane of the gastroduodenal region of 104 patients with different pathologies (gastritis and erosive ulcerative alterations) was investigated by polymerase chain reaction (PCR). Examination of the biopsy material revealed frequent occurrence of pathogenic strains of Helicobacter pylori (up to 80%) and Herpesviridae (EBV, HHV 6, HHV 7, HHV 8) in various combinations. In such cases it is necessary to use adequate antibacterial and antiviral therapy with individual choice of immunomodulators.

Preconception vaccination with a glycoprotein B (gB) DNA vaccine protects against cytomegalovirus (CMV) transmission in the guinea pig model of congenital CMV infection.

DNA vaccines expressing the guinea pig cytomegalovirus (GPCMV) homologs of the glycoprotein B (gB) and UL83 proteins were evaluated for protection against congenital GPCMV infection. After 4 doses of DNA administered by epidermal (gene gun) route, all guinea pigs developed enzyme-linked immunosorbent assay (ELISA) antibody and, for gB-vaccine recipients, neutralizing antibody. Dams were challenged with 1 x 10(4) plaque-forming units of GPCMV in the third trimester. Preconception vaccination with gB did not decrease overall pup mortality, although, within the gB-vaccine group, pup mortality was lower among dams with high ELISA responses. Preconception maternal vaccination with gB vaccine significantly reduced congenital transmission in liveborn pups. In contrast, UL83 vaccine had no significant effect on pup mortality or vertical transmission of GPCMV. Virus load was significantly lower in infected pups born to gB- and UL83-vaccinated dams than in infected pups born to control dams. These data support the concept that subunit gB vaccination may be useful in protecting against CMV-induced disease.

Quantitative-competitive PCR monitoring of viral load following experimental guinea pig cytomegalovirus infection.

Human cytomegalovirus (HCMV) is the most common cause of congenital viral infection in the developed world, and can lead to significant morbidity. Animal models of HCMV infection are required for study of pathogenesis, because of the strict species-specificity of cytomegalovirus (CMV). Among the small animal CMV models, the guinea pig CMV (GPCMV) has unique advantages, in particular its propensity to cross the placenta, causing disease in utero. In order to develop quantitative endpoints for vaccine and antiviral therapeutic studies in the GPCMV model, a quantitative-competitive PCR (qcPCR) assay was developed, based on the GPCMV homolog of the HCMV UL83 gene, GP83. Optimal amplification of GPCMV DNA was observed using primers spanning a 248 base pair (bp) region of this gene. A 91 bp deletion of this cloned fragment was generated for use as an internal standard (IS) for PCR amplification. Standard curves based upon the fluorescent intensity of full-length external target to IS were compared with signal intensity of DNA extracted from blood and organs of experimentally infected guinea pigs in order to quantify viral load. Viral load in newborn guinea pigs infected transplacentally was determined and compared with that of pups infected with GPCMV as neonates. Viral loads were highest in pups infected as neonates. The most consistent isolation and highest quantities of viral DNA were observed in liver and spleen, although viral genome could be readily identified in brain, lung, and salivary gland. Viral load determination should be useful for monitoring outcomes following vaccine studies, as well as responses to experimental antiviral agents.