Is ultra-violet radiation the main force shaping molecular evolution of varicella-zoster virus?

The global disease burden of varicella-zoster virus infection from 1990 to 2019

Data of global epidemiology of varicella-zoster virus infection (VZVI) is limited. This study aimed to investigate the burden of VZVI based on the Global Burden of Disease Study 2019 data. The age-standardized rates, including the incidence, death, disability-adjusted life years (DALYs), and the estimated annual percentage changes (EAPC) of VZVI were calculated to evaluate the disease burden of VZVI. The global numbers of incident and death cases due to VZVI were 83,963,744 and 14,553, respectively. The age-standardized incidence rate of VZVI increased slightly all over the world, while the age-standardized death and DALYs rate decreased from 1990 to 2019 (EAPC = -2.31 and -1.61, respectively). The younger age (<5 years old) and older groups had the highest VZVI burden. The high sociodemographic index (SDI) region had the highest age-standardized incidence rates in 2019 (1236.28/100,000, 95% UI: 1156.66-1335.50) and the low SDI region had the lowest incidence (1111.24/100,000, 95% UI: 1040.46-1209.55). The age-standardized death and DALYs rate of VZVI decreased with the increase of SDI. Amongst the 21 geographical regions, the high-income Asia Pacific (1269.08/100,000) region had the highest age-standardized incidence rate in 2019, while Sub-Saharan Africa had the highest age-standardized death and DALYs rate. The global incidence of VZVI has continued to increase in the past three decades, while the age-standardized death and DALYs rates have decreased. More attention should be paid to the younger and older population, as well as low SDI regions. This article is protected by copyright. All rights reserved.

Targeted Genome Sequencing Reveals Varicella-Zoster Virus Open Reading Frame 12 Deletion

The neurotropic herpesvirus varicella-zoster virus (VZV) establishes a lifelong latent infection in humans following primary infection. The low abundance of VZV nucleic acids in human neurons has hindered an understanding of the mechanisms that regulate viral gene transcription during latency. To overcome this critical barrier, we optimized a targeted capture protocol to enrich VZV DNA and cDNA prior to whole-genome/transcriptome sequence analysis. Since the VZV genome is remarkably stable, it was surprising to detect that VZV32, a VZV laboratory strain with no discernible growth defect in tissue culture, contained a 2,158-bp deletion in open reading frame (ORF) 12. Consequently, ORF 12 and 13 protein expression was abolished and Akt phosphorylation was inhibited. The discovery of the ORF 12 deletion, revealed through targeted genome sequencing analysis, points to the need to authenticate the VZV genome when the virus is propagated in tissue culture.IMPORTANCE Viruses isolated from clinical samples often undergo genetic modifications when cultured in the laboratory. Historically, VZV is among the most genetically stable herpesviruses, a notion supported by more than 60 complete genome sequences from multiple isolates and following multiple in vitro passages. However, application of enrichment protocols to targeted genome sequencing revealed the unexpected deletion of a significant portion of VZV ORF 12 following propagation in cultured human fibroblast cells. While the enrichment protocol did not introduce bias in either the virus genome or transcriptome, the findings indicate the need for authentication of VZV by sequencing when the virus is propagated in tissue culture.

Radiation-Induced Oral Mucositis

Radiation-induced oral mucositis (RIOM) is a major dose-limiting toxicity in head and neck cancer patients. It is a normal tissue injury caused by radiation/radiotherapy (RT), which has marked adverse effects on patient quality of life and cancer therapy continuity. It is a challenge for radiation oncologists since it leads to cancer therapy interruption, poor local tumor control, and changes in dose fractionation. RIOM occurs in 100% of altered fractionation radiotherapy head and neck cancer patients. In the United Sates, its economic cost was estimated to reach 17,000.00 USD per patient with head and neck cancers. This review will discuss RIOM definition, epidemiology, impact and side effects, pathogenesis, scoring scales, diagnosis, differential diagnosis, prevention, and treatment.

Varicella-Zoster Virus in Perth, Western Australia: Seasonality and Reactivation

Background

Identification of the factors affecting reactivation of varicella-zoster virus (VZV) largely remains an open question. Exposure to solar ultra violet (UV) radiation is speculated to facilitate reactivation. Should the role of UV in reactivation be significant, VZV reactivation patterns would generally be expected to be synchronous with seasonal UV profiles in temperate climates.

Methods

We analysed age and gender specific VZV notification time series data from Perth, Western Australia (WA). This city has more daily sunshine hours than any other major Australian city. Using the cosinor and generalized linear models, we tested these data for seasonality and correlation with UV and temperature.

Results

We established significant seasonality of varicella notifications and showed that while herpes-zoster (HZ) was not seasonal it had a more stable seasonal component in males over 60 than in any other subpopulation tested. We also detected significant association between HZ notifications and UV for the entire Perth population as well as for females and males separately. In most cases, temperature proved to be a significant factor as well.

Conclusions

Our findings suggest that UV radiation may be important for VZV reactivation, under the assumption that notification data represent an acceptably accurate qualitative measure of true VZV incidence.

Solar radiation and water vapor pressure to forecast chickenpox epidemics

The clear seasonality of varicella infections in temperate regions suggests the influence of meteorologic conditions. However, there are very few data on this association. The aim of this study was to determine the seasonal pattern of varicella infections on the Mediterranean island of Mallorca (Spain), and its association with meteorologic conditions and schooling. Data on the number of cases of varicella were obtained from the Network of Epidemiologic Surveillance, which is composed of primary care physicians who notify varicella cases on a compulsory basis. From 1995 to 2012, varicella cases were correlated to temperature, humidity, rainfall, water vapor pressure, atmospheric pressure, wind speed, and solar radiation using regression and time-series models. The influence of schooling was also analyzed. A total of 68,379 cases of varicella were notified during the study period. Cases occurred all year round, with a peak incidence in June. Varicella cases increased with the decrease in water vapor pressure and/or the increase of solar radiation, 3 and 4 weeks prior to reporting, respectively. An inverse association was also observed between varicella cases and school holidays. Using these variables, the best fitting autoregressive moving average with exogenous variables (ARMAX) model could predict 95 % of varicella cases. In conclusion, varicella in our region had a clear seasonality, which was mainly determined by solar radiation and water vapor pressure.

Epidemiology of varicella in Mexico

BACKGROUND

The epidemiological patterns of varicella-zoster virus (VZV) infection, which are strongly associated with climate, are characterized by more frequent infections occurring among children in temperate regions than in the tropics. In temperate regions, varicella exhibits a seasonal cyclic behavior in which the number of cases increases significantly during the winter and spring seasons, further supporting the role of environmental factors in disease transmission. However, the underlying mechanisms responsible for this distinctive behavior are not fully understood. In Mexico, information regarding the epidemiology of varicella is scarce, and the distribution of VZV infection has not been analyzed.

OBJECTIVES

In this article we investigate the epidemiological patterns of varicella in Mexico and their relationship with different environmental and demographic factors.

STUDY DESIGN

A retrospective study was conducted using the data reported by the National Center of Epidemiological Surveillance and Disease Control. The overall varicella incidence was calculated and associated with temperature, overcrowding, age, gender and population density.

RESULTS

The epidemiology of varicella showed an intriguing pattern, in which warmer regions were characterized by higher incidences than in temperate regions. Young children were the most affected age group. There was no correlation between varicella incidence and overcrowding or population density.

CONCLUSIONS

The epidemiology of varicella in Mexico significantly departs from the characteristic patterns observed in other tropical latitudes, with some features resembling those commonly associated with temperate regions.