Herpes Simplex Virus Type 2: An Update

Nurse Practitioner,  Nov 2003  by Mark, Hayley D,  Hanahan, Ashley P,  Stender, Stacie C

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Most primary practitioners are unaware that many of their sexually active patients are infected with herpes simplex virus type 2 (HSV-2). Approximately 22% of the adult population in the United States is infected.1 It is estimated that about 1.7 million new HSV-2 infections are acquired each year, and over half of new cases are asymptomatic or unrecognized.2 Most cases of genital herpes result from HSV-2 infection, although the incidence of genital herpes caused by herpes simplex virus type 1 (HSV-1) is increasing.3 HSV-1 is the virus that typically causes orolabial disease or "cold sores". Of significant concern is the role that HSV plays in human immunodeficiency virus (HIV) transmission. A recent review of the literature indicates that the risk of acquiring HIV is doubled for HSV-2 infected persons. In addition, genital ulcers facilitate HIV shedding in the genital tract of infected individuals, thereby increasing the likelihood of transmission to HIV-negative partners.4

* Epidemiology

Serum sample collection during the National Health and Nutrition Examination Surveys (NHANES) II and III, showed that among Caucasians in the general population, 15% of men and 20% of women are HSV-2 seropositive. Among African-Americans, 35% of men and 55% of women are seropositive.1 Herpes is more common in women than men, infecting approximately one out of four women and one out of five men. It is common in both rural and urban areas in the United States. Rates of HSV-2 have risen quickly among adolescents and young adults in particular. Over the past two decades, HSV-2 seroprevalence has quintupled in white teenagers and doubled among young adults in their 20s. Between 1976 and 1994, the prevalence of HSV-2 was 5.4% among persons aged 12 to 19 years and 17.2% among persons aged 20 to 29 years.1 Seroprevalence of HSV-2 is virtually nonexistent in persons younger than 12 years of age, peaks by the age of 40, and remains stable thereafter. HSV-1 infection is usually transmitted during childhood and adolescence and, if symptomatic, is commonly characterized by oral or facial lesions.5

* Presentation and Natural History

The physical manifestations of a genital herpes infection range from truly asymptomatic to severe disease. Immunosuppressed individuals or intrapartum-infected neonates are particularly vulnerable to severe consequences of a HSV infection. The most important aspect of clinical presentation for the NP to be aware of is that the "textbook" presentation of genital herpes is rarely seen. Herpes can masquerade as many other disorders, including: gonorrhea, non-gonococcal urethritis, syphilis, erosive lichen sclerosis, candidiasis, folliculitis, bacterial vaginosis, chancre, atopic dermatitis, Behcet's syndrome, human papillomavirus, vaginal fissure, excoriation, and trauma.6,7 Typical symptoms are internal and external itching, nondescriptive vaginal or urethral discomfort, dull perineal pain, or tissue feeling "raw" or irritated. Many women present complaining of "yeast infection" symptoms. Unfortunately, these symptoms are relatively generic and characterize many of the aforementioned disorders. Among the recent advances is the understanding of the extent of subclinical infections. Clinically mild infections that do not bring people to medical attention are common. This occurrence, combined with a low index of suspicion on the part of clinicians, has contributed to the vast underdiagnosis of HSV.8

HSV infection may be primary or nonprimary (see Table: "Type of HSV Infection, Clinical Symptoms, and Antibody at Presentation"). Primary infections are defined as first infection ever with either HSV-1 or HSV-2. Type-specific immune responses can take 8-12 weeks to develop following a primary infection and thus, at presentation, no serum antibody will be present. The characteristic picture of a primary infection includes multiple small, shallow, teardrop-like vesicles that often present in a linear or clustered fashion. These eruptions or ulcers may appear anywhere in the perineal or perianal area, including the urethra, rectum or vagina. Systemic symptoms are often associated with a primary infection and are consistent with a flu-like syndrome, including low-grade fever, myalgias and malaise.

Approximately 25% of patients with a first clinical episode of HSV-2 have had a prior asymptomatic primary infection and type specific antibody to HSV-2 will be present.9 Following primary infection, the virus becomes latent in local sensory ganglia, periodically reactivating to cause symptomatic or lesions, or asymptomatic, but infectious, viral shedding. Viral shedding occurs when there are no apparent symptoms, but virus can be obtained from the genital tract.

The definition of a nonprimary infection is a newly acquired infection with HSV-1 or HSV-2 in an individual previously seropositive for the other virus. Manifestations of nonprimary infections tend to be milder than primary infection. During a recurrent, symptomatic infection, antibody is present when symptoms appear, although the patient may not have been aware of previous episodes. Serologic testing reveals antibodies for HSV and the disease is usually mild and short in duration. Finally, many people have asymptomatic infection when serum antibody is present, but there is no known history of clinical outbreaks.