Effect of climatic factors and population density on varicella zoster virus epidemiology within a tropical country.

Lolekha, Somsak; Tanthiphabha, Watcharee; Sornchai, Penpark; Kosuwan, Pensri; Sutra, Sumit; Warachit, Boonyarat; Chup-Upprakarn, Suda; Hutagalung, Yanee; Weil, J.; Bock, Hans L.

doi:10.4269/ajtmh.2001.64.131

Cited by 146 publications

(134 citation statements)

References 12 publications

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“…6, 10 The wide age range of the cases in this outbreak is consistent with this pattern and similar to other tropical South-East Asia countries such as Malaysia, the Philippines and Thailand where more than 90% seroconversion can only be seen in those older than 30 years.…”

supporting

confidence: 61%

Hidden varicella outbreak, Luang Prabang Province, the Lao People’s Democratic Republic, December 2014 to January 2015

Sengkeopraseuth

Bounma²,

Siamong

et al. 2016

WPSAR

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supporting

confidence: 61%

Hidden varicella outbreak, Luang Prabang Province, the Lao People’s Democratic Republic, December 2014 to January 2015

Sengkeopraseuth

Bounma²,

Siamong

et al. 2016

WPSAR

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“…Ninety-two isolates were E1 genotype strains (67 from Australia and 25 from New Zealand), 38 were genotype E2 (30 from Australia and 8 from New Zealand), 15 (Table 2). No BglI Ϫ PstI Ϫ isolates were identified in this study, although a double-negative isolate was described in an earlier study from Australia (3).…”

Section: Resultsmentioning

confidence: 99%

“…Varicella displays a marked seasonality (peaking in late winter or spring) in temperate climates, and infection is nearly ubiquitous by age 20. For reasons that remain unclear, seasonality does not occur in tropical countries, and a larger proportion of people enter adulthood uninfected by VZV (14,15). In addition, several studies have demonstrated a distinctive geographic distribution of the major VZV genotypes aligning with cool versus warm global climates (2,18,28).…”

mentioning

confidence: 99%

Identification of Five Major and Two Minor Genotypes of Varicella-Zoster Virus Strains: a Practical Two-Amplicon Approach Used To Genotype Clinical Isolates in Australia and New Zealand

Loparev

Rubtcova

Boštíková

et al. 2007

J Virol

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Whole genome phylogenetic analysis in this study resolved a total of five major genotypes among the 22 varicella-zoster virus (VZV) strains or isolates for which complete genomic sequences are available. Consistent with earlier publications we have designated these genotypes European 1 (E1), European 2 (E2), Japanese (J), mosaic 1 (M1), and mosaic 2 (M2). Single nucleotide polymorphism (SNP) analysis performed in a whole-genome alignment revealed that VZV isolates of all five genotypes can be accurately genotyped using SNPs from two amplicons: open reading frame 22 (ORF22) and either ORF21 or ORF50. This modified approach identifies all of the genotypes observed using any of the published genotyping protocols. Of 165 clinical varicella and zoster isolates from Australia and New Zealand typed using this approach, 67 of 127 eastern Australian isolates were E1, 30 were E2, 16 were J, 10 were M1, and 4 were M2; 25 of 38 New Zealand isolates were E1, 8 were E2, and 5 were M1. VZV strain diversity in eastern Australia is thus broader than has been described for any other region, including Europe, Africa, and North America. J strains were far more prevalent than previously observed in countries other than Japan. Two-amplicon typing was in complete accord with genotypes derived using SNP in multiple ORFs (ORFs 1, 21, 22, 38, 50, 54, and 62). Two additional minor genotypes, M3 and M4, could also be resolved using two-amplicon typing.Varicella (chickenpox) results from primary infection with varicella-zoster virus (VZV), which characteristically occurs early in life and usually follows a benign course (1). A lifelong latent infection is established on first exposure and can reactivate, typically after age 50, to cause zoster (shingles). VZV can be transmitted to susceptible persons from either disease condition, although zoster carries a significantly lower risk of transmission. Transmission from zoster can reintroduce strains that were circulating decades earlier and, as such, likely contributes to the genetic stability of VZV. The epidemiology of VZV infection varies geographically. Varicella displays a marked seasonality (peaking in late winter or spring) in temperate climates, and infection is nearly ubiquitous by age 20. For reasons that remain unclear, seasonality does not occur in tropical countries, and a larger proportion of people enter adulthood uninfected by VZV (14, 15). In addition, several studies have demonstrated a distinctive geographic distribution of the major VZV genotypes aligning with cool versus warm global climates (2,18,28). It is unclear whether the strain distribution is actually driven primarily by climate or by other factors, such as immigration patterns.A number of methods have been reported for identifying and genotyping VZV strains (4,18,21). Early VZV typing efforts relied on DNA restriction fragment length polymorphism (RFLP) analysis, an approach that first demonstrated the high degree of sequence conservation among VZV strains. Nevertheless, some intrastrain variation among wild-type i...

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“…There is no previous study in this province to compare VZV prevalence in two sexes. However, no difference was found in the VZV seropositivity in other studies in Iran (5) and some other parts of the world (13)(14)(15).…”

Section: Discussionmentioning

confidence: 38%

Seroprevalence of Varicella Zoster Infection at Provincial Level in Iranian Adolescents: The CASPIAN-III Study

Mostafavi

Hoseini

Kelishadi

et al. 2017

Arch Pediatr Infect Dis

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Background: Although primary varicella zoster virus (VZV) infection (chicken pox) is a mild childhood disease, it can cause severe infection with complications in adults. As the disease is preventable by effective vaccination, it is important to determine the level of immunity to VZV in every region to implement proper vaccination strategies. Objectives: The aim of this study was to investigate the seroprevalence of VZV infection in adolescents living in different provinces of Iran. Methods: In a cross-sectional multicentre study, serum samples from 2315 students, aged 10 -18 years, were examined for VZV antibodies (IgM/IgG). Students were selected by multistage cluster sampling during a national surveillance program. Results: Prevalence of VZV antibodies was statistically different in various provinces of Iran (P = 0.001); it ranged from 82.4% in Isfahan, Center of Iran, to 98.5% in Mazandaran, North of the country. The VZV seroprevalence was not significantly different by gender, except for Khuzestan, South of Iran, where antibodies were much more prevalent in girls (92.7%) than in boys (78.3%, P = 0.004). Seroprevalence was not significantly different according to the living area (urban/rural). Conclusions: VZV seroprevalence is different in various provinces of Iran; the susceptibility of adult population to VZV infection is suggested to be high in Ardabil, Isfahan, and Kermanshah; and low in Kerman and Mazandaran. Therefore, different strategies should be implemented in each province to protect high-risk adults from severe varicella infection.

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Effect of climatic factors and population density on varicella zoster virus epidemiology within a tropical country.

Cited by 146 publications

References 12 publications

Hidden varicella outbreak, Luang Prabang Province, the Lao People’s Democratic Republic, December 2014 to January 2015

Hidden varicella outbreak, Luang Prabang Province, the Lao People’s Democratic Republic, December 2014 to January 2015

Identification of Five Major and Two Minor Genotypes of Varicella-Zoster Virus Strains: a Practical Two-Amplicon Approach Used To Genotype Clinical Isolates in Australia and New Zealand

Seroprevalence of Varicella Zoster Infection at Provincial Level in Iranian Adolescents: The CASPIAN-III Study

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