Varicella-zoster Virus Isolates Research Articles

Genomic sequencing revealed recombination event between clade 1 and clade 2 occurs in circulating varicella-zoster virus in China.

Varicella-zoster virus (VZV), a member of the Alphaherpesvirinae subfamily, causes varicella in primary infections and establishing a latent stage in sensory ganglia. Upon reactivation, VZV causes herpes zoster with severe neuralgia, especially in elderly patients. The mutation rate for VZV is comparatively lower than the other members of other alpha herpesviruses. Due to geographic isolation, different genotypes of VZV are circulating on separate continents. Here, we successfully isolated a VZV from the vesicular fluid of a youth zoster patient. Based on the single-nucleotide polymorphism profiles of different open reading frames that define the genotype, this newly isolated VZV primarily represents genotype clade 2 but also has characteristics of genotype clade 1. The next-generation sequencing provided a nearly full-length sequence, and further phylogenetic analysis revealed that this VZV isolate is distinct from clades 1 and 2. The Recombination Detection Program indicates that a possible recombinant event may occur between the VZV isolate and clade 1. In summary, we found that there is a circulating VZV isolate in China that may represent a recombinant between clade 1 and clade 2, providing new concerns that need to be considered in the future VZV vaccination program.

Practical aspects on identification, cultivation and characteristics of varicella-zoster virus isolates

Until now, it has been considered that infectivity of the varicella-zoster virus (VZV) is closely related to target cell, and newly formed virus is not released into the culture medium. It is also known that it is hard to grow VZV in cell cultures, due to its slow replication rate and a limited range of sensitive cell cultures. In addition, VZV isolation depends on type of cell culture used, nature of clinical material, presence of viable virus and transport time. Objectives. To study production of infectious extracellular VZV in various cell cultures. Materials and methods. Eight cell cultures were used, including human embryonic diploid lung cells and human embryonic dermomuscular tissue (KM-27), as well as continuous human and monkey cell lines. Crusts detached from vesicular lesions were used as clinical isolates, which were placed into cryo-vials added with transport medium and transferred in liquid nitrogen. VZV infectivity was assessed in cell cultures by using hemo-adsorption assay with erythrocyte suspension isolated from guinea pig or human zero group blood and confirmed by indirect immunofluorescence with polyclonal sera from varicella or herpes zoster convalescents. Results. There were examined 27 clinical samples consisting of crusts from vesicular lesions isolated from patients with chickenpox, as well as one sample from 63-year old patient with exacerbated recurrent herpes zoster. Primary infection with clinical isolates was performed on diploid human lung embryo cells (HLEC) at low temperature. It was found that clinical samples collected within day 1–18 inclusive after the onset of skin eruption were able to induce cytopathic effects in HLEC cell monolayer such as cytolysis around dermal crusts. Specificity of cytopathic effect was confirmed by using real-time polymerase chain reaction (RT-PCR). Viral antigens were prepared on 7 cell lines infected with the laboratory strain Ellen VZV (USA) to assess the immune sera. A high anti-VZV specificity of mouse sera was detected by ELISA while all the lysates of infected cell lines were used as the solid-phase sorbent. In experiments on VZV reproduction demonstrated that extracellular virus was released into the culture medium starting from day 1 after infection of target cells, and infectivity of the virus-containing fluid ascends during further cultivation.

Varicella in Tshuapa Province, Democratic Republic of Congo, 2009-2014.

To describe varicella cases in Tshuapa Province of the Democratic Republic of the Congo identified during monkeypox surveillance. Demographic, clinical and epidemiological data were collected from each suspected monkeypox case 2009-2014. Samples were tested by PCR for both Orthopoxviruses and varicella-zoster virus (VZV); a subset of VZV-positive samples was genotyped. We defined a varicella case as a rash illness with laboratory-confirmed VZV. There were 366 varicella cases were identified; 66% were ≤19 years old. Most patients had non-typical varicella rash with lesions reported as the same size and stage of evolution (86%), deep and profound (91%), on palms of hands and/or soles of feet (86%) and not itchy (49%). Many had non-typical signs and symptoms, such as lymphadenopathy (70%) and sensitivity to light (23%). A higher proportion of persons aged ≥20 years than persons aged ≤19 years had ≥50 lesions (79% vs. 65%, P = 0.007) and were bedridden (15% vs. 9%, P = 0.056). All VZV isolates genotyped from 79 varicella cases were clade 5. During the surveillance period, one possible VZV-related death occurred in a 7-year-old child. A large proportion of patients presented with non-typical varicella rash and clinical signs and symptoms, highlighting challenges identifying varicella in an area with endemic monkeypox. Continued surveillance and laboratory diagnosis will help in rapid identification and control of both monkeypox and varicella and improve our understanding of varicella epidemiology in Africa.

Genotypes of clinical varicella-zoster virus isolates from Manaus, Brazil.

Vaccination against varicella-zoster virus (VZV) has been effective and safe in countries that routinely administer the vaccine. Brazil began universal VZV vaccination in 2013. This study aimed to identify VZV genotypes present in Manaus, Brazil prior to widespread immunization. Vesicular lesions or cerebral-spinal-fluid samples were collected from patients diagnosed with VZV, herpes zoster, or meningitis/encephalitis. DNA was extracted, amplified, and sequenced. Half the isolates were clade-5 viruses and the remaining were divided between the European clades 1 and 3. This study provides insights into the circulating VZV genotypes in Manaus prior to widespread vaccination.

Genetic polymorphism of thymidine kinase (TK) and DNA polymerase (pol) of clinical varicella-zoster virus (VZV) isolates collected over three decades

BackgroundGenotypic resistance testing of varicella-zoster virus (VZV) strains to antivirals is of high relevance in immunocompromised patients with VZV reactivations unresponsive to therapy. However, the knowledge on mutations associated with natural gene polymorphism or resistance is limited. ObjectivesTo examine the genotype of the thymidine kinase (TK) and DNA polymerase (pol) of unselected clinical VZV isolates collected between 1984 and 2014 and to verify the phenotype related to novel amino acid (aa) substitutions. Study designThe TK and DNA pol genes of 169 VZV isolates were analyzed by amplification and sequencing. Sequences were compared to that of the reference strain Dumas. The phenotype to acyclovir and other antivirals was examined in isolates with novel aa substitutions using modified plaque reduction assay. ResultsIn the TK of four strains, four different aa substitutions were detected, apart from the known change S288L that was present in all strains compared to Dumas. All four substitutions have hitherto not been described in the literature and were phenotypically classified as natural gene polymorphisms although two out of them (S51L, K186R) were localized in conserved gene centers. The DNA pol of 34 isolates exhibited 19 different substitutions, 14 out of them were novel, and two (R753K, V777I) were within conserved gene regions. Again, these changes were characterized as natural gene polymorphisms. ConclusionsNon-synonymous mutations in VZV TK or DNA pol conferring natural gene polymorphism are rare events. Nevertheless, the phenotypic characterization of 18 novel polymorphisms can help to provide a better identification of resistance mutations.

Role of the JNK Pathway in Varicella-Zoster Virus Lytic Infection and Reactivation.

Mechanisms of neuronal infection by varicella-zoster virus (VZV) have been challenging to study due to the relatively strict human tropism of the virus and the paucity of tractable experimental models. Cellular mitogen-activated protein kinases (MAPKs) have been shown to play a role in VZV infection of nonneuronal cells, with distinct consequences for infectivity in different cell types. Here, we utilize several human neuronal culture systems to investigate the role of one such MAPK, the c-Jun N-terminal kinase (JNK), in VZV lytic infection and reactivation. We find that the JNK pathway is specifically activated following infection of human embryonic stem cell-derived neurons and that this activation of JNK is essential for efficient viral protein expression and replication. Inhibition of the JNK pathway blocked viral replication in a manner distinct from that of acyclovir, and an acyclovir-resistant VZV isolate was as sensitive to the effects of JNK inhibition as an acyclovir-sensitive VZV isolate in neurons. Moreover, in a microfluidic-based human neuronal model of viral latency and reactivation, we found that inhibition of the JNK pathway resulted in a marked reduction in reactivation of VZV. Finally, we utilized a novel technique to efficiently generate cells expressing markers of human sensory neurons from neural crest cells and established a critical role for the JNK pathway in infection of these cells. In summary, the JNK pathway plays an important role in lytic infection and reactivation of VZV in physiologically relevant cell types and may provide an alternative target for antiviral therapy.IMPORTANCE Varicella-zoster virus (VZV) has infected over 90% of people worldwide. While primary infection leads to the typically self-limiting condition of chickenpox, the virus can remain dormant in the nervous system and may reactivate later in life, leading to shingles or inflammatory diseases of the nervous system and eye with potentially severe consequences. Here, we take advantage of newer stem cell-based technologies to study the mechanisms by which VZV infects human neurons. We find that the c-Jun N-terminal kinase (JNK) pathway is activated by VZV infection and that blockade of this pathway limits lytic replication (as occurs during primary infection). In addition, JNK inhibition limits viral reactivation, exhibiting parallels with herpes simplex virus reactivation. The identification of the role of the JNK pathway in VZV infection of neurons reveals potential avenues for the development of alternate antiviral drugs.

Antiviral resistance in herpes simplex virus and varicella-zoster virus infections: diagnosis and management.

Aciclovir (ACV) is the first-line drug for the management of herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections. Long-term administration of ACV for the treatment of severe infections in immunocompromised patients can lead to the development of drug resistance. Furthermore, the emergence of isolates resistant to ACV is increasingly recognized in immunocompetent individuals with herpetic keratitis. This review describes the mechanisms involved in drug resistance for HSV and VZV, the laboratory diagnosis and management of patients with infections refractory to ACV therapy. Genotypic testing is more frequently performed for the diagnosis of infections caused by drug-resistant HSV or VZV isolates. Molecular biology-based systems for the generation of recombinant viruses have been developed to link unknown mutations with their drug phenotypes. Fast and sensitive methods based on next-generation sequencing will improve the detection of heterogeneous viral populations of drug-resistant viruses and their temporal changes during antiviral therapy, which could allow better patient management. Novel promising compounds acting on targets that differ from the viral DNA polymerase are under clinical development. Antiviral drug resistance monitoring for HSV and VZV is required for a rational use of antiviral therapy in high-risk populations.

Complementary assays for monitoring susceptibility of varicella-zoster virus resistance to antivirals

The emergence of varicella-zoster virus (VZV) resistance to current antivirals as acyclovir (ACV) constitutes a hindrance to antiviral treatment effectiveness of VZV infections, especially in immunocompromised patients. The molecular mechanisms of VZV resistance reported so far rely on the presence of mutations within thymidine kinase (TK, ORF36) and DNA polymerase (ORF28) viral genes. The aim of this work was to develop reliable and complementary diagnostic methods to detect VZV antiviral resistance: (i) a genotypic assay based on TK and DNA polymerase genes sequencing, (ii) a plaque reduction assay to determine antiviral 50% effective concentrations, and (iii) a functional assay to evaluate in vitro phosphorylation activity of recombinant TKs. As a whole, this study included the analysis of 21 VZV clinical isolates and 62 biological samples from patients experiencing VZV infection. Genetic analysis revealed 3 and 9 new amino acid changes that have not been previously described within the highly conserved TK and DNA polymerase, respectively. Then, VZV isolates bearing newly identified mutations considered as natural polymorphisms were characterized as susceptible to ACV using plaque-reduction assay in MeWo cells. In parallel, the impact of TK changes on ACV phosphorylation activity was examined using a nonradioactive in vitro enzymatic assay.

Genotyping of clinical varicella-zoster virus isolates collected from Yunnan in Southwestern China.

Varicella-zoster virus (VZV) belongs to the α-herpesvirus family. Genetically, it is stable and is divided into several genotypes based upon the genetic variations. The genotypes of VZV are rarely studied in the Southwestern region of China. In the present study, the common genetic variations in the VZV genes were examined in 42 VZV isolates collected from the patients with herpes zoster in the Yunnan province (Southwestern China). The restriction fragment length polymorphism analysis of open reading frames (ORFs) 38, 54 and 62 in the VZV genes showed that all the collected VZV isolates were PstI, BglI and SmaI positive. The R5 variable-repeat region in these isolates was variable (R5A: 46.4%; R5B: 53.6%). The sequencing data of ORFs 1, 21, 22 and 54 indicated that 41 of the 42 collected VZV isolates could be grouped into genotype J or J1. Only one VZV isolate was identified as genotype A1 or M2. No new substitutions in the sequenced fragments were found in the collected VZV isolates. The results of the present study provided a preliminary genetic characterization of the VZV strains in the Yunnan province of Southwestern China.

Genotype analysis of varicella-zoster virus isolates from suburban Shanghai Municipal Province, China.

To determine the predominant genotype of the varicella-zoster virus (VZV) in suburban Shanghai Municipal Province, specimens were collected from the lesions of 95 outpatients clinically diagnosed with varicella or herpes zoster. Of these, 69 patients (72.6%) were positive for VZV DNA. The 69 isolates were all genotyped as the genotype J1/clade 2. Based on sequencing of the 447 bp sequence in ORF22, 66 isolates were identified as genotype J/clade 2 strains and three were identified as type M2/clade 4 strains. To confirm the classification of these three strains, we determined the presence of 27 single-nucleotide polymorphisms (SNPs) and found that isolates 1270/1450 shared seven SNPs that differed from those of clade 2, in which three SNPs were unique to clade 3 and another three were unique to clade 4. Isolate 1456 had two markers of clade 4 that differed from clade 2. The phylogenetic tree showed that our isolates clustered primarily with clade 2 and that the three M2/J1 strains clustered between clades 2 and 4. It is likely that isolates 1270/1450/1446 may represent a new subclade of either clade 2 or 4, or some recombinant events. In addition, our isolates were WT strains. We also observed significant inter-strain variations.

Ramsay-Hunt syndrome in the differential diagnosis of stroke

An 82-year-old man with a medical history of diabetes, hypertension, and right hemispheric stroke 4 years previously, presented to the emergency department complaining of pain in the right ear, otorrhea, and hypoacusis for 5 days. His spouse also mentioned symptoms of drooling and aggravation of previous defi cits, namely dysarthria, facial asymmetry, and left hemiparesis. Due to the suspicion of a new stroke event, a neurological evaluation was requested, which revealed right peripheral facial palsy (Figure A), ipsilateral hypoacusis, and spastic left hemiparesis with impaired deambulation without support. An ear inspection revealed various blistering lesions and cicatricial tissue on the right external auditory canal (Figure B). Routine blood analysis was normal, and cerebral computed tomography showed no recent lesions, particularly ischemic or hemorrhagic lesions. The cerebrospinal fluid investigation revealed pleocytosis (75 cells, 95% of which were mononuclear), normal glucose and protein values, and negative results for the microbiological investigation, including unsuccessful isolation of varicella zoster virus (VZV). The patient was treated with acyclovir (800mg 5 times daily) and REFERENCES

Varicella-Zoster Viruses Associated with Post-Herpetic Neuralgia Induce Sodium Current Density Increases in the ND7-23 Nav-1.8 Neuroblastoma Cell Line

Post-herpetic neuralgia (PHN) is the most significant complication of herpes zoster caused by reactivation of latent Varicella-Zoster virus (VZV). We undertook a heterologous infection in vitro study to determine whether PHN-associated VZV isolates induce changes in sodium ion channel currents known to be associated with neuropathic pain. Twenty VZV isolates were studied blind from 11 PHN and 9 non-PHN subjects. Viruses were propagated in the MeWo cell line from which cell-free virus was harvested and applied to the ND7/23-Nav1.8 rat DRG x mouse neuroblastoma hybrid cell line which showed constitutive expression of the exogenous Nav 1.8, and endogenous expression of Nav 1.6 and Nav 1.7 genes all encoding sodium ion channels the dysregulation of which is associated with a range of neuropathic pain syndromes. After 72 hrs all three classes of VZV gene transcripts were detected in the absence of infectious virus. Single cell sodium ion channel recording was performed after 72 hr by voltage-clamping. PHN-associated VZV significantly increased sodium current amplitude in the cell line when compared with non-PHN VZV, wild-type (Dumas) or vaccine VZV strains ((POka, Merck and GSK). These sodium current increases were unaffected by acyclovir pre-treatment but were abolished by exposure to Tetrodotoxin (TTX) which blocks the TTX-sensitive fast Nav 1.6 and Nav 1.7 channels but not the TTX-resistant slow Nav 1.8 channel. PHN-associated VZV sodium current increases were therefore mediated in part by the Nav 1.6 and Nav 1.7 sodium ion channels. An additional observation was a modest increase in message levels of both Nav1.6 and Nav1.7 mRNA but not Nav 1.8 in PHN virally infected cells.

Genetic Analysis of Clinical VZV Isolates Collected in China Reveals a More Homologous Profile

Forty-four varicella-zoster virus (VZV) isolates from China were genotyped by using a scattered single nucleotide polymorphism (SNP) method, including open reading frames (ORFs) 1, 22, 31, 37, 60, 62, 67, and 68. Based on the analysis of the polymorphic markers in the 8 ORFs, all of the 44 isolates can be placed in genotype J defined by the SNP profiles in ORF22 or clade B defined by the SNP profiles in ORFs 31, 37, 60, 62, 67, and 68. The three consecutive nucleotide (CGG) in-frame insertions in ORF 1 were found in 8 (18.2%) isolates, which has not been described in VZV strains from any other part of the world. A novel synonymous A>G substitution in ORF60 was revealed in 4 (9.1%) of the isolates. In addition, a previously described three consecutive nucleotide (ATC) insertion in ORF 60 was found in all the Chinese isolates but not in the US isolate MLS. The results showed all the 44 strains that belong to genotype J/clade B with significantly high homogeneity, and phylogenetic analysis suggested that the 44 Chinese isolates consist of 4 clusters, but interstrain variations also exist. Overall, VZV isolates obtained in China showed significantly higher genetic homogeneity than isolates reported from other countries.

Research on the genotypes of clinical varicella-zoster virus isolates in Tibet

Objective To analyze the genotypes of clinical varicella-zoster virus(VZV) isolates in Tibet.Methods The samples of vesicular fluid from patients with chickenpox or zoster were collected to isolate VZV in human embryonic fibroblast cells.Furtherly,the isolated VZV were identified by indirect immunofluorescence assay and the positive ones were continuely cultured in vitro to get their genome DNAs.Then,PCR and nucleotide sequencing were performed on the part of open reading frames 1,21,50,54.To confirm the genotypes of isolated virus strains,the gene sequences obtained from PCR products were compared with that in GenBank of VZV Dumas strains,and their restriction enzyme sites were analyzed via Primer 5.0.Results Ten clinical isolates of VZV were obtained from sixteen specimens,the positive isolation rate was 62.5％.Gene analysis showed that among all the ten clinical isolates of VZV in Tibet,three strains are genotype A1,four are genotype A2 and the other three are genotype J1.Conclusion The VZV genotype distribution in Tibet was tightly related to their special geographic locations. Key words: Varicella-zoster virus ; Single nucleotide polymorphism ; Genotype ; Tibet area

Molecular characterization of varicella‐zoster virus clinical isolates from 2006 to 2008 in a tertiary care hospital, Dublin, Ireland, using different genotyping methods

Varicella-zoster virus (VZV), a herpesvirus, is a ubiquitous organism that causes considerable morbidity worldwide and can cause severe complications on reactivation. Phylogenetic analysis was performed on 19 clinical VZV isolates (16 zoster and 3 varicella) found in Ireland, between December 2006 and November 2008, in order to determine whether previously reported viral heterogeneity was still present and whether viral recombination was evident. Open reading-frames (ORFs) from genes 1, 21, 50, and 54, were sequenced. Clades 1, 2, 3, and 5 were identified. Four putative recombinant isolates were detected (three clade 3/1 and one clade 5/3/1). Further sequencing and examination of ORF 22 and 21/50, did not elucidate the putative recombinant genotypes further. These two previously published genotyping schemes were examined in light of the new consensus genotyping scheme proposed in 2010. Remarkable VZV heterogeneity remains prevalent in Ireland. This is the first evidence of putative VZV recombination found in Ireland.

Resistance testing of clinical varicella-zoster virus strains

Acyclovir resistance of varicella-zoster virus (VZV) has been reported in rare cases of immunocompromised patients. In this study, the natural polymorphism of the thymidine kinase (TK) and DNA polymerase (pol) genes was examined in 51 clinical VZV isolates sensitive to acyclovir (ACV). In addition, 16 VZV strains with clinical resistance to ACV were analyzed. None of the ACV-sensitive strains of the clades 1, 3 and 5 showed gene polymorphism of the TK. By contrast, the DNA pol gene exhibited polymorphism-related substitutions as a function of the VZV clade. The novel substitutions M286I, E824Q, R984H and H1089Y were detected in strains of clades 3 and 5. In the TK gene of 7 VZV strains with clinical ACV resistance, the novel substitutions L73I, A163stop, W225R, T256M, N334stop and the deletion of nucleotides 19–223 were found to be associated most likely with resistance. In one strain showing the substitution W225R, ACV resistance could be confirmed by the viral phenotype. In the DNA pol gene, the novel amino acid substitutions T237K and A955T could be detected, but their significance remains unclear. In conclusion, the characterization of resistance using genetic analysis of the TK and DNA pol genes has to be considered the method of choice for the determination of VZV resistance to antiviral drugs. In a considerable number of patients with clinical ACV-resistant VZV infections, resistance cannot be verified by virological methods.

Assessment of transcriptomal analysis of varicella-zoster-virus gene expression in patients with and without post-herpetic neuralgia

Varicella-Zoster virus (VZV) is a human herpes virus that reactivates from a latent state in human trigeminal and dorsal root ganglia to cause herpes zoster (shingles) which is a painful vesicular dermatomal skin eruption. The major complication of herpes zoster is post-herpetic neuralgia (PHN) which is a serious condition occurring especially in individuals over 50 years. PHN is extremely painful, may be permanent, and is frequently very refractory to all treatment. The ability to identify those patients with herpes zoster who are likely to develop PHN would be highly beneficial as it would allow pre-emptive anti-viral therapy. We have assessed the potential of using long oligonucleotide VZV microarrays to determine whether MeWo cells infected with VZV isolates obtained from 13 patients with zoster who had subsequently developed PHN showed significant transcriptomal differences from MeWo cells infected with viruses isolated from ten zoster patients who had not developed PHN. We found that viral gene expression from sample to sample within a group (PHN patients or non-PHN patients) varied as much, or more, than the viral gene expression between those groups. Quantitative real-time polymerase chain reaction studies carried out on 11 open reading frames on four representative viral infected MeWo cell lines (two from each group) confirmed the transcriptomal heterogeneity between the two groups. Growth curve analyses of ten representative infected cell lines (five from each group) showed that PHN and non-PHN-associated viruses replicated equally efficiently. Taken together, these findings suggest that viral microarray-based transcriptomal measurements are unlikely to prove of clinical utility in predicting the incidence of PHN.

The Parental Strain of the Attenuated Virus (vOka) Used in the Varicella Vaccine Is Circulating in China: Implications for Vaccine Surveillance

Varicella-zoster virus (VZV) is the etiological agent of both varicella (chickenpox) and herpes zoster (shingles). Primary infection with VZV causes varicella, which usually occurs in childhood. Reactivation of VZV in previously infected individuals results in a herpes zoster that occurs most commonly in the elderly. In 1974, a live-attenuated VZV strain was established and subsequently licensed for vaccination in Japan (1). Comparison of the complete DNA sequences of the Oka vaccine strain (vOka) and the parental Oka strain (pOka) revealed there were only 42 nucleotide substitutions along the whole 125-kbp viral genome, 15 of which were located in the major transactivator ORF62 region (2). The high sequence homology between vOka and pOka increases the difficulty of distinguishing vOka from clinical isolates with the pOka genotype. The pOka-like wild-type strain constitutes 20–30% of all VZV isolates in Japan (3). In contrast, it seems a rare genotype in other countries such as the U.S. and Australia (4,5). In this study we report a case of herpes zoster infected by the pOka-like wild-type strain in a Chinese woman. A 27-year-old woman who was 8 months pregnant presented to the First Affiliated Hospital of Anhui Medical University (Hefei, China) with vesicle skin lesions. The diagnosis of zoster was made mainly based on the history and features of the rash. The zoster rashes had developed on the right side of her abdomen, and she had no post-herpetic neuralgia. VZV was isolated in human embryonic lung fibroblasts from vesicle fluid taken from the patient on day 2 after the onset of zoster and was identified by immunocytochemistry with monoclonal antibodies to VZV glycoprotein E (Biodesign International ® , Saco, Maine, USA). This strain is hereafter designated as ZW strain. Serologic assay by fluorescent antibody to the membrane antigen (FAMA) test revealed a specific VZV IgG antibody titer of 1:8 in the serum colleted on day 2, and 1:256 in the second serum specimen obtained 16 days after the onset of symptoms. Viral DNA was extracted from the fluid of the rash vesicles

Simultaneous Cocirculation of Both European Varicella-Zoster Virus Genotypes (E1 and E2) in Mexico City

Full-length genome analysis of varicella-zoster virus (VZV) has shown that viral strains can be classified into seven different genotypes: European (E), Mosaic (M), and Japanese (J), and the E and M genotypes can be further subclassified into E1, E2, and M1 through 4, respectively. The distribution of the main VZV genotypes in Mexico was described earlier, demonstrating the predominance of E genotype, although other genotypes (M1 and M4) were also identified. However, no information regarding the circulation of either E genotype in the country is available. In the present study, we confirm the presence of both E1 and E2 genotypes in the country and explore the possibility of coinfection as the triggering factor for increased virulence among severe cases. A total of 61 different European VZV isolates collected in the Mexico City metropolitan area from 2005 to 2006 were typed by using a PCR method based on genotype-specific primer amplification. Fifty isolates belonged to the E1 genotype, and the eleven remaining samples were classified as E2 genotypes. No coinfection with both E genotypes was identified among these specimens. We provide here new information on the distribution of VZV genotypes circulating in Mexico City.

Genetic analysis of clinical varicella-zoster virus isolates collected in China

To study the genetic characteristics of vaccine and varicella-zoster virus (VZV) strains isolated from patients with chickenpox or zoster by molecular analysis. SNP based VZV genetic characteristics were analyzed in 19 VZV isolates using the restriction fragment length polymorphisms analysis of DNA fragments of the open reading frames 6, 38, 62 and sequence alignment of the open reading frames 1, 31, 51, 62. All vaccine strains were revealed AluI(-) PstI(-) SmaI(+) BssHII(+) NaeI(+), 96% clinical isolates were revealed AluI(+) PstI(+) SmaI(-) BssHII(-) NaeI(-), 2% clinical isolates were revealed AluI(-) PstI(-) SmaI(+) BssHII(+), 2% clinical isolates were revealed AluI(+) PstI(-) SmaI(-) BssHII(-) NaeI(-) by restriction fragment length polymorphisms analysis and sequence alignment revealed the mutations also presented in this four vaccine strains. Use the restriction fragment length polymorphisms analysis of DNA fragments of the open reading, frames 6 and 62 could be distinguished VZV wild-type strains and vaccine strain in clinical isolates in China. In order to find the adverse effect caused by vaccine from certain company's, analysis on the SNPs in ORFs 1, 31, 51 and 62 is needed.