Varicella zoster viral disease

Increase in the genetic polymorphism of varicella-zoster virus after passaging in in vitro cell culture

Primary infections with the varicella-zoster virus (VZV) result in varicella, while latent reactivation leads to herpes zoster. Both varicella and zoster can be prevented by live attenuated vaccines. There have been reports suggesting that both clinical VZV strains and those in vaccine preparations are genetically polymorphic, containing mixtures of both wild-type and vaccine-type sequences at certain vaccine-specific sites. In this study, the genetic polymorphism of the VZV genome was examined by analyzing the frequencies of minor alleles at each nucleotide position. Next-generation sequencing of the clinical VZV strain YC02 passaged in an in vitro cell culture was used to identify genetically polymorphic sites (GPS), where the minor allele frequency (MAF) exceeded 5%. The number of GPS increased by 7.3-fold at high passages (p100) when compared to low passages (p17), although the average MAF remained similar. GPS were found in 6 open reading frames (ORFs) in p17, 35, and 54 ORFs in p60 and p100, respectively. GPS were found more frequently in the dispensable gene group than the essential gene group, but the average MAF was greater in the essential gene group. The most common two major/minor base pairs were A/g and T/c. GPS were found in all three passages at 16 positions, all located in the reiterated (R) region. The population diversity as measured by Shannon entropy increased in p60 and p100. However, the entropy remained unchanged in the R regions.

Herpes zoster incidence in a multicenter cohort of solid organ transplant recipients

BACKGROUND

Immunosuppressed patients are at increased risk for herpes zoster (HZ), but incidence in solid organ transplant (SOT) recipients has varied in multiple studies. To assess incidence of HZ, we examined patients who underwent SOT and received follow-up care within the large multicenter US Department of Veteran's Affairs healthcare system.

METHODS

Incident cases of HZ were determined using ICD-9 coding from administrative databases. A multivariable Cox proportional hazards model, adjusted for a priori risk factors, was used to assess demographic factors associated with development of HZ.

RESULTS

Among the 1077 eligible SOT recipients, the cohort-specific incidence rate of HZ was 22.2 per 1000 patient-years (95% confidence interval [CI], 18.1-27.4). African Americans (37.6 per 1000 [95% CI, 25.0-56.6]) and heart transplants recipients (40.0 per 1000 [95% CI, 23.2-68.9]) had the highest incidence of HZ. Patients transplanted between 2005 and 2007 had the lowest incidence (15.3 per 1000 [95% CI, 8.2-28.3]). In a multivariable model, African Americans (hazard ratio [HR] 1.88; 95% CI: 1.12, 3.17) and older transplant recipients (HR 1.13; 95% CI: 1.01, 1.27 [per 5-year increment]) had increased relative hazards of HZ.

CONCLUSIONS

These data demonstrate that HZ is a common infectious complication following SOT. Future studies focused on HZ prevention are needed in this high-risk population.

Horner's syndrome with an ipsilateral X nerve palsy following presumed shingles

Herpes zoster is a common clinical problem but its complications, apart from post-herpetic neuralgia, are comparatively rare. We describe a case of Horner's syndrome and ipsilateral vagal paresis following likely herpes zoster of the third and fourth cervical roots. This unusual combination has not, to our knowledge, been previously described.

[Varicella-zoster virus infections]

The primary infection with varicella-zoster virus (VZV) is manifest clinically as varicella. It is a common very contagious disease, normally appearing in childhood. VZV is a ubiquitous virus with a high prevalence. Clinically it is characterized by pleomorphic skin lesions. Normally antiviral therapy is necessary only in severe cases, in adults or in immunosuppressed patients. Herpes zoster, also caused by (VZV), is a neurodermal disease representing the endogenous relapse of the primary varicella infection. Herpes zoster is characterized by lesions concentrated in the innervation region of a cranial or spinal nerve. One of the most feared manifestations of herpes zoster is pain. Several antiviral drugs are approved and many studies have shown that antiviral therapy, started early in the course of disease, can significantly reduce risk and duration of postherpetic neuralgia in elderly patients. Therefore, antiviral therapy in combination with an adequate pain management should be given to all elderly patients as soon as herpes zoster is diagnosed.

The consistency of shingles and its significance for health monitoring

Accurate estimation of monitored populations is essential for epidemiological study. Many countries do not have systems of patient registration and routine disease surveillance is thereby hindered. We studied the incidence of shingles over time and investigated the hypothesis that the incidence is consistent and could be used as a proxy for estimating the monitored population. Annual incidence rates of shingles reported in the Weekly Returns Service (WRS) since 1970 and in the Dutch Sentinel Network (DSN) over the period 1998--2001 were studied. Gender specific annual rates (1998--2001) were compared after standardising for age. The population in the DSN was estimated by applying the WRS incidence rates to the numbers of DSN incident cases. The incidence of shingles was annually and seasonally consistent. Incidence in males was similar in both networks and in females approximately 18% greater in the WRS: in age groups 15-64 years, incidence was similar in both networks, but in children 0-14 years and in persons 65 years and over, it was higher in the WRS. The total populations in the DSN estimated from average age/gender specific rates in the WRS were within 12% of the observed in each of the 4 years surveyed. The incidence of shingles in the two countries was sufficiently close to estimate the surveyed population aged 15-64 years from knowledge of incident cases in the community. Routine monitoring of shingles in sentinel practice networks is commended as a method of assuring recording quality and as a means of estimating the survey population where the registered population is not known.

Roscovitine, a cyclin-dependent kinase inhibitor, prevents replication of varicella-zoster virus

Understanding the interactions between varicella-zoster virus (VZV) and host cells can be addressed by using small molecule inhibitors of cellular enzymes. Roscovitine (Rosco) is a purine derivative that inhibits cyclin-dependent kinase 1 (cdk1), cdk2, cdk5, cdk7, and cdk9, which are key regulators of the cell cycle and transcription. Herpesviruses are known to interact with cell cycle proteins; thus, the antiviral effects of Rosco on VZV growth were evaluated. In a plaque reduction assay, 25 micro M Rosco prevented VZV replication, and the antiviral effect was reversible for at least up to 24 h posttreatment. Rosco also reduced expression of the major transactivator, IE62, over 48 h. Confocal microscopy studies indicated that Rosco caused the immediate-early proteins ORF4 and IE62 to abnormally localize in infected cells and prevented cell-cell spread of VZV over 48 h. Rosco was found to inhibit VZV DNA synthesis as measured by real-time PCR, and this technique was used to estimate the 50% effective concentration (EC(50)) of 14 micro M. This value was close to the EC(50) estimate of 12 micro M determined from plaque reduction assays. At 25 micro M, Rosco was not cytotoxic over 48 h in a neutral red uptake assay, and proliferation was slowed as the cells accumulated in a G(2)-like state. These results demonstrate the importance of cdk's in VZV replication and suggest that cdk inhibitors could serve as useful VZV antivirals.

Detection of varicella zoster virus in genital specimens using a multiplex polymerase chain reaction

OBJECTIVE

To compare the relative proportions of varicella zoster virus (VZV) and herpes simplex viruses in specimens obtained from the genital lesions of adults presenting with presumed genital herpes infection.

METHODS

Swabs of genital lesions from 6210 patients attending general practices, infectious diseases clinics within hospitals, or sexual health centres for treatment of their genital lesions were tested using polymerase chain reaction (PCR) technology. The multiplexed PCR was capable of detecting herpes simplex virus types 1 and 2 (HSV-1, HSV-2), VZV, and cytomegalovirus in a single sample.

RESULTS

A total of 2225 patients had viruses detected by PCR. HSV-1 was detected in 36%, HSV-2 in 61%, and VZV in 2.9% of PCR positive samples. Of the 65 patients with VZV genital infection, many were thought to have HSV infection before laboratory testing.

CONCLUSIONS

The finding of VZV in nearly 3% of virus positive genital specimens demonstrates that this virus needs to be considered as a differential diagnosis for genital herpetic lesions. Advice provided to patients with VZV genital infection regarding the source of infection, likelihood of recurrence, and potential for transmission of the virus will be different from that given to patients with HSV infection.