Literature review > Issue_5 > Review on Ndjoyi-Mbiguino et al. 

Several studies have noted the synergistic interaction between HIV and HSV-2, and interventional trials that try to define the causality of infections with these two viruses are in progress. Recent development and commercialization of type-specific HSV-2 antibody tests have helped to assess the prevalence and incidence of HSV-2 infection in various populations and are the main tests on which epidemiologic studies have been based. However, the need for tests to detect viral shedding in the genital track remains, as it is the viral replication in the epithelium and not latent virus in the ganglia that is the likely contributor to the HIV-HSV-2 interaction.

Ndjoyi-Mbiguino et al. compared the yield of 2 specimen collection methods for HSV-2 in the female genital track: a dry swab of the endocervical canal vs. cervico-vaginal wash (lavage). The samples were then processed by real-time PCR with a lower limit of detection of 400 copies/ml of wash or 400 copies/?g of swab sample. Among 188 HSV-2 seropositive, HIV-seronegative women, the frequency of HSV detection was 6.9% in cervical samples and 13.3% in cervicovaginal lavage samples. No sample was positive by swabbing only. The amount of HSV DNA in the swabs that were found to be positive by both methods was closely correlated, r=0.87, P<.0001. The authors conclude that the cevicovaginal method is preferred for detection of HSV DNA in genital secretions. The paper is a welcomed addition to growing literature on the clinical and virologic manifestations of HSV infection among developing countries populations in whom the natural history of genital herpes has been poorly characterized.

However, several issues are not addressed adequately in this study. First, the study population is not well described; we learn that the women were free of genital ulcer disease or genital inflammation, although a large number presented with vaginal discharge. More precise characterization of their work-up would have been useful, especially given the recent observations of interactions between HSV-2 and bacterial vaginosis. Second, HSV is a virus that reactivates over a large aspect of the genital area. Unlike gonorrhea, chlamydia, or HIV, the pathogen is not concentrated in the cervical secretions. Clinical involvement of the cervix is mostly limited to initial infection, and vaginal wall infection with HSV is distinctly unusual. The most common place for HSV reactivation in women is vulva and the perianal area [1]. This is especially true for women with established infection in whom cervical shedding becomes infrequent. The authors recognize that the wide area of sampling is likely to account for higher yield of the lavage vs. endocervical swab. However, the yield may have been even higher if the swab was also rolled over the vulva and the perianal area. Third, the sampling of the cervix only makes these results difficult to compare with results of other studies that sampled a wider genital region [2]. This also becomes important when we try to extend the findings to men, in whom a lavage is not possible, yet in whom we believe HSV-2 also plays an important role.

References:

1. Wald A, Zeh J, Selke S, Ashley RL, Corey L. Virologic characteristics of subclinical and symptomatic genital herpes infections. N Engl J Med 1995;333:770-5.

2. Baeten JM, McClelland RS, Corey L, Overbaugh J, Lavreys L, Richardson BA, et al. Vitamin A supplementation and genital shedding of herpes simplex virus among HIV-1-infected women: a randomized clinical trial. J Infect Dis 2004;189(8):1466-71.

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