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Herpes simplex virus (HSV-1 and HSV-2) infections are found worldwide, even in remote populations. Nearly all adults have antibodies to HSV-1 by the fifth decade of life, and the seroprevalence of HSV-2 has increased at an alarming rate over the last decade. Herpes simplex virus (HSV) infections occur throughout the year. The incubation period ranges from 1 to 26 days (median 6-8 days). Contact with active ulcerated lesions or asymptomatically excreting persons can result in transmission. The efficiency of transmission is greater during symptomatic periods of viral excretion. HSV has been isolated from nearly all visceral and mucocutaneous sites and is associated with a variety of clinical syndromes including mucocutaneous infections, central nervous system and visceral infections. HSV infections vary widely in severity, from common cold sores to life-threatening infections in infants and immunocompromised hosts. Both viral subtypes, HSV 1 & 2, can cause genital and oral-facial infections. HSV lesions persist 15 to 20 days in primary infections and about 10 days in recurrent infections. HSV lesions progress through several stages from maculopapules, vesicles, pustules, ulcers, and crusted surfaces. The amount of virus present in lesions is a function of the duration of the infection. The earliest lesions, maculopapules through pustules, contain the highest virus titers. Titers of recoverable virus decline precipitously once the epithelial surface ulcerates. Differentiation of HSV-1 from HSV-2 is important prognostically, since genital HSV-2 infection is twice as likely to reactivate and recurs 8-10 times more frequently than genital HSV-1 infections. Likewise, oral-labial HSV-1 infection recurs more frequently than oral-labial HSV-2 infection. Viral culture has been the gold standard for the diagnosis of mucocutaneous lesions. With the introduction of real-time PCR technology, herpes virus detection can be accomplished much more rapidly. Recent studies have shown real-time PCR to be more sensitive and equally specific compared to virus culture for the identification of HSV in genital lesions. Parallel testing of 139 genital specimens received for herpes culture by our virology laboratory had the following results:
In addition to enhanced sensitivity, PCR results are available the same or next day instead of 3 to 5 days required for culture. The charge for PCR is comparable to culture and specimen collection is the same. The CPT code is 87529. The earliest lesions need to be sampled to decrease the incidence of false negatives. Fluid should be aspirated from vesicles with a tuberculin syringe and transferred to viral transport media. If lesions are crusted, remove the crust with a scalpel blade and swab the basal membrane to obtain infected epithelial cells. Dacron, rayon, or cotton swabs should be used and not calcium alginate swabs. Swabs should be immediately placed in viral transport media. All specimens should be refrigerated after collection. |
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