Detection of herpes simplex virus in genital specimens by type-specific polymerase chain reaction

Diagnostics for Herpes Simplex Virus

Herpes simplex virus (HSV) is one of the most common, yet frequently overlooked, sexually transmitted infections. Since the type of HSV infection affects prognosis and subsequent counseling, type-specific testing to distinguish HSV-1 from HSV-2 is recommended. Although PCR has been the diagnostic standard for HSV infections of the central nervous system, until now viral culture has been the test of choice for HSV genital infection. However, HSV PCR, with its consistently and substantially higher rate of HSV detection, will likely replace viral culture as the gold standard for the diagnosis of genital herpes in people with active mucocutaneous lesions, regardless of anatomic location or viral type. Alternatively, type-specific serologic tests based on glycoprotein G should be the test of choice to establish the diagnosis of HSV infection when no active lesion is present. Given the difficulty in making the clinical diagnosis of HSV, the growing worldwide prevalence of genital herpes and the availability of effective antiviral therapy, there is an increased demand for rapid, accurate laboratory diagnosis of patients with HSV.

The laboratory diagnosis of herpes simplex virus infections

Herpes simplex virus (HSV) types 1 and 2 cause genital herpes infections and are the most common cause of genital ulcer disease in industrialized nations. Although these infections are very common, the majority of them remain underdiagnosed because they are asymptomatic or unrecognized. A clinical diagnosis of genital herpes should always be confirmed by laboratory testing; this can be accomplished through the use of direct tests for viral isolation, the detection of antigen or, more recently, the detection of HSV DNA using molecular diagnostic techniques. Testing for serotypes is recommended because of the different prognostic and counselling implications. Type-specific HSV serology is becoming more readily available and will enhance the ability to make the diagnosis and guide clinical management in select patients.

The diagnosis of genital herpes - beyond culture: An evidence-based guide for the utilization of polymerase chain reaction and herpes simplex virus type-specific serology

Accurate identification of persons with genital herpes is necessary for optimal patient management and prevention of transmission. Because of inherent inaccuracies, clinical diagnosis of genital herpes should be confirmed by laboratory testing for the causative agents herpes simplex virus type 1 (HSV-1) and HSV type 2 (HSV-2). Further identification of the HSV type is valuable for counselling on the natural history of infection and risk of transmission. Laboratory methods include antigen detection, culture, polymerase chain reaction (PCR) and conventional and type-specific serology (TSS). PCR has, by far, the greater sensitivity and should be the test of choice for symptomatic cases. HSV-2 TSS is indicated for patients with genital lesions in whom antigen detection, culture or PCR fail to detect HSV, and for patients who are asymptomatic but have a history suggestive of genital herpes. HSV-2 TSS is further indicated for patients infected with HIV. HSV-2 TSS along with HSV-1 TSS may be considered, as appropriate, in evaluating infection and/or immune status in couples discordant for genital herpes, women who develop their first clinical episode of genital herpes during pregnancy, asymptomatic pregnant women whose partners have a history of genital herpes or HIV infection, and women contemplating pregnancy or considering sexual partnership with those with a history of genital herpes. The above should be performed in conjunction with counselling of infected persons and their sex partners.

Rapid polymerase chain reaction assay to detect herpes simplex virus in the genital tract of women in labor

OBJECTIVE

To develop a rapid quantitative real-time polymerase chain reaction (PCR) to detect herpes simplex virus (HSV) in the genital secretions of women that may be used in labor.

METHODS

Samples of genital secretions from women in labor, swabs of active genital lesions, and swabs of buffer solution were analyzed using a newly developed rapid HSV PCR assay to detect HSV glycoprotein B gene and quantitate virion copy number. A previously validated TaqMan PCR to detect HSV glycoprotein B gene was performed as the comparator gold standard. Positivity determination that optimized sensitivity and specificity was determined with receiver operating characteristic curves.

RESULTS

The median time to result for rapid HSV PCR was 2 hours (range 1.5-3.5 hours). A positivity determination rule that required both wells of the rapid test to detect 150 copies or greater of HSV per milliliter maximized specificity (96.7%) without appreciable loss of sensitivity (99.6%). Among positive samples, the correlation between the rapid test and TaqMan for the quantity of HSV isolated was excellent (R=0.96, P<.001). The rapid test had a positive predictive value of 96.7% and a negative predictive value of 99.6% in a population with HSV shedding prevalence of 10.8%, based on the prevalence of genital HSV previously found among HSV-2 seropositive women in labor.

CONCLUSION

Rapid HSV PCR provides results with excellent sensitivity and specificity within a timeframe that could inform clinical decision making for identifying neonates at risk of neonatal HSV infection.

LEVEL OF EVIDENCE

II.

Interactions and management issues in HSV and HIV coinfection

Significant synergistic interactions have been observed between HIV and herpes simplex virus (HSV). HIV-induced immune compromise can cause frequent and persistent HSV disease, while poorly controlled HSV replication may influence HIV pathogenicity and transmission. HSV-2 seroprevalence is high in HIV-infected cohorts worldwide, with rates of over 80% for HSV-1 and ranging from 33% to more than 80% for HSV-2. As seen in HIV-negative individuals, HSV-2 coinfection is associated with female gender, older age and black ethnicity. HSV infection is commonly under-diagnosed in HIV-infected individuals, although the use of PCR for HSV detection in mucocutaneous swabs and HSV type-specific serology can improve the diagnostic yield. In HIV-1-infected patients with frequent clinical episodes of HSV reactivation, suppressive antiviral therapy may prove beneficial in controlling HSV disease while also reducing HSV-mediated promotion of HIV replication. Antiretroviral therapy leads to a gradual recovery of HSV-specific T-cell responses and a reduction in HSV-related morbidity, indicating that successful management of coinfection should target both HIV and HSV replication. The aim of this review is to address the more speculative issues surrounding the management of HSV/HIV coinfection and to summarize the data that inform them.

Increasing relative prevalence of HSV-2 infection among men with genital ulcers from a mining community in South Africa

OBJECTIVES

To determine the aetiology of genital ulcer disease (GUD) and its association with HIV infection in the mining community of Carletonville, South Africa, from two cross sectional surveys of consecutive men presenting with genital lesions during October 1993 to January 1994 and July to November 1998.

METHODS

A multiplex polymerase chain reaction (M-PCR) assay combined with amplicon detection was used to identify DNA specific sequences of Treponema pallidum, herpes simplex virus (HSV), and Haemophilus ducreyi. A real time PCR assay was used to differentiate between HSV-1 and HSV-2.

RESULTS

M-PCR detected T pallidum, HSV, and H ducreyi in 10.3%, 17.2%, and 69.4% of 232 GUD patients during 1993-4 and in 12.4%, 36.0%, and 50.5% of 186 GUD patients in 1998. The proportion of patients with more than one agent increased significantly from 7.3% (17/232) in 1993-4 to 16.7% (31/186) in 1998 (p <0.01). HSV-2 was detected in a higher proportion of ulcer specimens from HIV infected patients than in specimens from HIV uninfected patients during both time periods (1993-4: 26.2% v 6.7%, p <0.001; 1998: 42.1% v 29.6%, p >0.09).

CONCLUSIONS

Based on two cross sectional surveys, 4 years apart, chancroid remained the leading cause of GUD in men who presented at the STD clinic with genital ulcers in the mining community of Carletonville, South Africa. The relative prevalence of primary syphilis has remained low. However, HSV-2 has emerged as a more significant cause of GUD and the proportion of GUD patients infected with more than one agent also increased significantly. HSV-2 DNA was detected in a significantly higher proportion of ulcer specimens from HIV positive patients than from HIV negative patients. No association was found between HIV infection status and the relative prevalence of chancroid or syphilis.

[Herpes and skin lesions: what's new?]

The spectrum of clinical lesions of herpes has grown, since the research of viruses by PCR permitted to bind to their etiology discrete or atypical lesions, and even, to display periods of asymptomatic viral excretion. These variable clinical aspects depend on the balance between, on the one hand, the qualitative and quantitative virulence of HSV and, on the other hand, the quality of the immunological defenses of the patient. So, "herpetic primary infection" and "herpetic recurrences" are serological definitions; the clinical aspects of the different stages can be interchangeable. Cultures or PCR and type-specific serologies also showed the increased frequency of HSV1 in genitals, explained by the increased oro-genital sex, since the beginning of AIDS.

Using the evidence base on genital herpes: optimising the use of diagnostic tests and information provision

There have been several important advances in the range of available diagnostic tests for genital herpes simplex virus (HSV) infection in recent years; polymerase chain reaction (PCR) is emerging in routine clinical use and the potential role of type specific serological tests is currently under debate. Several large trials of prophylactic vaccines, subsequently proved to be ineffective, have expanded knowledge of the transmission and epidemiology of HSV infection. This article discusses optimal application of recent research evidence to clinical care, structured around the key issues for patients and their partners. These include acquisition and transmission of genital HSV-1 and HSV-2 infection, the natural history of genital herpes, and the role of partner notification.

Polymerase chain reaction for diagnosis of genital herpes in a genitourinary medicine clinic

BACKGROUND

Polymerase chain reaction (PCR) has well established advantages over culture for diagnosis of herpes viruses, but its technical complexity has limited its widespread application. However, recent methodological advances have rendered PCR more applicable to routine practice.

AIM

To compare automated PCR with viral culture for diagnosis of genital herpes.

METHODS

We studied 236 patients presenting with clinical features suggestive of genital herpes at an inner city genitourinary medicine clinic. Two swabs were taken from each patient. Cell culture and typing were performed by standard methods. Automated PCR was performed using the LightCycler instrument and the infecting viral type was determined by restriction endonuclease digestion of amplicons.

RESULTS

109 patients (46%) had a positive test for herpes simplex virus (HSV). In 88, both PCR and culture were positive; in 21 PCR only was positive. With both detection methods, lesion duration and morphology were associated with HSV detection. Compared with culture alone, use of PCR increased sensitivity by 13.3% in specimens from vesicular lesions, by 27.4% from ulcerative lesions, and by 20.0% from crusting lesions.

CONCLUSIONS

We advocate adoption of automated PCR as an efficient HSV detection and typing method for diagnosis of genital herpes in routine clinical practice. PCR allowed rapid laboratory confirmation of the diagnosis and increased the overall HSV detection rate by 24%.