title: Epidemiology of human herpesvirus 6 (HHV-6) infection in pregnant and nonpregnant women.
abstract: BACKGROUND
  Human herpesvirus 6 (HHV-6) is a ubiquitous virus primarily associated with benign conditions such as febrile syndromes and exanthem subitum (roseola infantum). Sexual, horizontal, and vertical transmission have been suggested. Little information is available regarding HHV-6 infection in women of reproductive age.
  
  
  OBJECTIVE
  Describe epidemiology of HHV-6 infection in pregnant and nonpregnant women.
  
  
  METHODS
  The study sample consisted of 569 women, age 18-45, who attended a university family planning clinic (nonpregnant, n=224) and two obstetrics clinics (pregnant [first trimester], n=345) in San Antonio, TX between October 1995 and May 1998. Blood and a vaginal swab, as well as sociodemographic information, were collected from each participant. Plasma was tested for HHV-6 IgG antibodies using a standard immunofluorescence assay (IFA). Lysed material from vaginal swabs was tested for HHV-6 DNA by polymerase chain reaction (PCR). Products were screened by enzyme-linked immunosorbent assay and positive tests were confirmed by repeat PCR followed by Southern analysis. PCR-positive samples were subtyped using an established method.
  
  
  RESULTS
  All subjects were HHV-6 antibody positive. Geometric mean titers of HHV-6 antibodies were significantly higher among nonpregnant versus pregnant women. Moreover, a higher proportion of nonpregnant versus pregnant women had antibody titers >/=160 and >/=320. This association persisted even after adjusting for a number of sociodemographic and clinical factors. Low rates of HHV-6 shedding in the genital tract were observed for both groups (pregnant, 7/297 [2.0%]; nonpregnant, 8/214 [3.7%]). Of 14 samples subtyped, four (29%) were subtype A.
  
  
  CONCLUSIONS
  The present study showed that 100% of the study sample was infected with HHV-6. Higher HHV-6 antibody titers, however, were noted in nonpregnant women. Both groups shed virus at low rates in the genital tract. HHV-6 subtype A was identified more commonly than previously reported. Further longitudinal studies are required to assess the consequences of maternal HHV-6 infection.
authors.affiliation: Departments of Pediatrics, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, USA.
authors.forename: J
authors.initials: J
authors.lastname: Baillargeon
authors.forename: J
authors.initials: J
authors.lastname: Piper
authors.forename: C T
authors.initials: CT
authors.lastname: Leach
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D004279:DNA, Viral / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006566:Herpesviridae Infections / Q000453:epidemiology* / Q000821:virology; D015654:Herpesvirus 6, Human / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology* / Q000821:virology
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral