HSV-2 can reactivate throughout the genital tract

Genital herpes caused by a reactivation of herpes simplex virus type 2 (HSV-2) is generally treated as a lesion in one specific area of the genital region. A new study, however, finds that the virus can frequently reactivate throughout the genital tract, an important new concept that could help guide both HSV-2 treatment and prevention. Now available online (http://www.journals.uchicago.edu/doi/abs/10.1086/650302), the study appears in the Feb. 15 issue of the Journal of Infectious Diseases.

In the study, Christine Johnston, MD, MPH, and colleagues at the University of Washington and the Fred Hutchinson Cancer Research Center in Seattle collected daily samples during a 30-day period from seven separate genital sites in four women infected with HSV-2. HSV-2 was detected from more than one anatomic site on 56 percent of days when there was viral shedding-and on genital surfaces on both sides of the participants' bodies on most days when virus was detected at more than one site.

Using a detailed sampling method and a sensitive assay, the authors showed that both symptomatic and asymptomatic HSV-2 reactivations often occurred at widely spaced regions throughout the genital tract. These reactivations were often on both sides of the body, even though clinical lesions typically emanate from one anatomic spot. The study's findings illustrate an important new concept in HSV-2 pathogenesis, the authors wrote, and may help in developing comprehensive treatment that both suppresses and limits the transmission of HSV-2 infection.

The authors also noted limitations of their study, including a small sample size and the unique features of the study's subjects. For example, all participants had a history of symptomatic genital herpes, and three of the four had acquired HSV-2 infection within the past year, increasing the chances of high viral reactivation and lesion rates. Additionally, although there were a high proportion of days with lesions during the study period, two of the participants who had recently acquired genital herpes contributed the majority of lesion days.

In an accompanying editorial, Edward W. Hook III, MD, of the University of Alabama at Birmingham, called the study's findings "of great potential importance, as they further challenge widely held beliefs regarding genital herpes and, by extension, its management." Many clinicians treat patients with newly diagnosed herpes episodically, managing the signs and symptoms of periodic symptomatic recurrences, Dr. Hook wrote. "From a personal and public health perspective, the biology of the infection suggests that a national campaign for serological testing of those at risk would provide the foundation for more effective efforts to control HSV transmission to others, and that for most sexually active persons with HSV-2 whose sex partners are not known to also be infected, suppressive therapy should be the preferred approach."