title: Varicella zoster virus quantitation in blood from symptomatic and asymptomatic individuals.
abstract: Primary infection with varicella zoster virus (VZV) occurs in immunocompromised and immunocompetent individuals. Clinical and asymptomatic reactivation with shedding of infectious virus and viremia may occur. The prevalence of VZV viremia is unknown. The aim of this study was to detect VZV viremia and quantify VZV DNA using quantitative polymerase chain reaction (qPCR) in blood from different populations. A qPCR-based method using EvaGreen® was used to quantify VZV DNA in 491 samples, including whole blood, plasma and buffy-coat, from patients hospitalized with varicella-associated disease (Group 1, n=10) and three groups with no VZV disease: individuals with a first clinical diagnosis of central nervous system demyelination (Group 2, n=213) with their age and sex-matched controls (Group 3, n=218); and HIV-infected individuals (Group 4, n=50). VZV-specific IgG antibody titres were measured in Group 3. The proportion positive for viremia and mean detectable VZV DNA load (copies/ml) were: Group 1: 100% (10/10) and 4.6 × 10(6) ± 1.4 × 10(7) ; Group 2: 4% (9/213) and 1.5 × 10(3) ± 1.8 × 10(4) ; Group 3: 8% (17/218) and 1.1 × 10(3) ± 7.8 × 10(3) ; Group 4: 12% (6/50) and 7.7 × 10(1) ± 2.8 × 10(2) . VZV DNA load and IgG titres were not significantly correlated (Group 3 only). VZV load in Group 1 was significantly elevated compared to Groups 2-4 (P<0.001); the latter were not significantly different from each other (P=0.05). VZV genotypes from clades 1-5 were identified in Group 1. VZV DNA was detected but at low frequency and viral load in both immunocompetent and immunocompromised individuals asymptomatic for VZV infection, compared to individuals with active VZV infection.
authors.affiliation: Clinical Virology, Centre for Infectious Diseases and Microbiology-Public Health and Laboratory Services, Institute of Clinical Pathology and Medical Research, Westmead Hospital and University of Sydney, Westmead, NSW, Australia. cheryl.toi@swahs.health.nsw.gov.au
authors.forename: Cheryl S
authors.initials: CS
authors.lastname: Toi
authors.forename: Meav-Lang J
authors.initials: ML
authors.lastname: Lay
authors.forename: Robyn
authors.initials: R
authors.lastname: Lucas
authors.forename: Choo Beng
authors.initials: CB
authors.lastname: Chew
authors.forename: Janette
authors.initials: J
authors.lastname: Taylor
authors.forename: Anne-Louise
authors.initials: AL
authors.lastname: Ponsonby
authors.forename: Dominic E
authors.initials: DE
authors.lastname: Dwyer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D001769:Blood / Q000821:virology*; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D005838:Genotype; D006562:Herpes Zoster / Q000821:virology*; D014645:Herpesvirus 3, Human / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction; D019562:Viral Load; D014766:Viremia / Q000821:virology*; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; D007074:Immunoglobulin G