Genital Herpes Virus Can Repeatedly Reactivate in Genital Tract
By Nancy Fowler Larson
Medscape Medical News
January 27, 2010 — Herpes simplex virus type 2 (HSV-2) can regularly reactivate throughout the genital tract, a finding that may affect treatment and prevention, according to a study published online January 20 and in the February 15 print edition of the Journal of Infectious Diseases.
"Longitudinal studies in HSV-2–seropositive persons have shown that HSV reactivates in the genital tract in >90% of persons," write Christine Johnston, MD, MPH, and colleagues at the University of Washington and the Fred Hutchinson Cancer Research Center in Seattle. "Anatomic patterns of genital HSV-2 reactivation have not been intensively studied."
Researchers examined 4 HSV-2–seropositive women with a history of symptomatic genital herpes. The primary infection occurred a median of 1 year before the study. Participants were observed every day for 30 days, and samples were collected from 7 different genital locations each time. To detect antibodies to HSV-1 and HSV-2, serum was assayed by HSV Western blot. DNA from swab samples underwent quantitative HSV polymerase chain reaction. The participants took no antiviral medication during the trial.
The findings were documented as follows:
HSV was found on 136 (16%) of 840 swab samples from 44 (37%) of the 120 patient days.
Lesions were recorded on 35 (29%) of the 120 days.
HSV was discovered at more than 1 anatomic site on 25 (57%) of 44 days in which there was HSV shedding (median, 2 sites; range, 1 - 7) and was noted on both sides of the body on 20 (80%) of the 25 days.
Visible lesions had a significant relationship with documented HSV from any genital location (incident rate ratio [IRR], 5.41; 95% confidence interval [CI], 1.24 - 23.50; P = .02) and with the number of positive sites (IRR, 1.19; 95% CI, 1.01 - 1.40; P = .03).
The maximum HSV copy number found was related to the number of positive sites (IRR, 1.62; 95% CI, 1.44 - 1.82; P < .001).
"These results demonstrate that genital HSV reactivation may occur simultaneously from multiple sacral ganglia; the mechanism behind these observations requires further investigation," the authors write.
Limits to the study included the small number of participants and some of their specific characteristics. In 3 of the 4 subjects, the initial infection occurred within a year of the study's initiation. Their relatively new infections raised the probability that both viral reactivation and lesions numbers would be high. Furthermore, the 2 women who had most recently contracted herpes accounted for most of the lesion days. The authors acknowledged the value of a more diverse cohort.
"Whether widespread subclinical reactivation occurs in HSV-2–seropositive persons without a clinical history of HSV-2, or in persons with long-standing HSV-2 infection, requires further study," the authors write.
In an editorial published with the findings, Edward Hook III, MD, from the University of Alabama at Birmingham and Jefferson County Department of Health, notes that 1 in 5 Americans has genital herpes but only about 10% are diagnosed. Dr. Hook called for a national campaign for serological testing of those at high risk to provide the basis for better prevention. He also advocated suppressive therapy for sexually active men and women who have HSV-2 infection but whose partners are not known to be infected.
"This would not be a simple task. Clinicians would need to reconceptualize their approach to diagnosis and management," Dr. Hook said. "In addition, there would be a need to portray genital herpes not as a 'scarlet letter' but rather as a widespread untoward consequence of human sexuality, the impact of which on personal and public health could be reduced through broader testing and more aggressive treatment."
The National Institutes of Health/National Institute of Allergy and Infectious Diseases supported the study. Several study authors have received funding from or have consulted for the National Institutes of Health, GlaxoSmithKline, Antigenics, Astellas, Aicuris, and/or Immune Design Corporation. One coauthor directs the University of Washington Virology Laboratory, which has been instrumental in diagnosing HSV infections. A full list of disclosures is available at the end of the journal article.
J Infect Dis. Published online January 20, 2010. Print publication February 15, 2010;201:486-487, 499-504.
