Literature review > Issue_6 > Review on Page et al. 

Genital herpes simplex virus (HSV) infection is a significant public health disease worldwide causing substantial morbidity and transmission potential. It is important that an accurate diagnosis be made by clinicians, as this has a major psychological, social, as well as sexual impact on patients and their sexual partners. A number of new type-specific serology tests were introduced in 2001 that can effectively distinguish HSV-1 and HSV-2 with high sensitivities and specificities. They can differentiate antibody responses to both HSV1 and HSV2 and are based on either western blot or glycoprotein G assays [1].

This study by Page et al. compares the performance of HSV-1 and HSV-2 IgM antibody detection using type-specific serology testing (TSST) with clinical diagnosis in patients presenting with first episode genital herpes. A number of points pertaining to the study design need to be addressed. The TSST used for the detection of HSV-2 IgG antibodies was an "in house" indirect ELISA test, whereas HSV-1 IgG, HSV-1 IgM and HSV-2 IgM antibodies were detected using western blot. It may have been simpler and more cost effective to use the HerpeSelect® ELISA test from Focus Technologies, which is FDA approved and shown to have high specificities and sensitivities for the detection of both HSV-1 and HSV-2 antibodies. This data could then be compared with other studies using similar FDA approved test kits.

Patients recruited into the study presented within 4 weeks of the onset of genital symptoms. In view of the limited time frame regarding the serological presence of IgM antibodies, it may have been better to recruit patients who only presented between 1 and 3 weeks from the onset of symptoms. Therefore, the 18 patients need not have been excluded from analysis due to "unreliable serology". However this presents limitations to the practical usage of the TSST for IgM antibodies in patients presenting with first episode genital herpes. Of the 157 patients recruited into the study, 31 patients were excluded and it may have been better for the overall analysis of the TSST significance tests to include these. Two of these were patients with virus isolated although with no serological evidence after 4 weeks; such patients are relevant to the study and should not have been excluded.

Virus isolation in cell culture is the currently used "gold standard" diagnostic test for genital herpes simplex virus infection. However this test is limited by being slow and labour intensive and its sensitivity declines according to the lesion duration at the time of sampling [2]. Clinical diagnosis has also been shown in several studies not to be accurate as a diagnostic tool. A study using a multiplex PCR method found varicella zoster virus in nearly 3% of specimens taken from patients with presumed genital herpes infection [3]. Polymerase chain reaction (PCR) has been proven to be a more rapid and sensitive diagnostic tool for genital HSV infection [4, 5].

This study using IgM serology in the management of patients with first episode genital herpes has shown an acceptable sensitivity and specificity of TSST. It would be interesting if future studies were conducted comparing the TSST with PCR, rather than clinical diagnosis with virus culture, in order to examine the value of these diagnostic kits. However, in clinical practice, all of these tests are expensive and their cost effectiveness in the setting of sexual health clinics must be considered in future work.

References:

1. Scoular A. Using the evidence base on genital herpes: optimizing the use of diagnostic tests and information provision. Sex Trans Inf 2003 June; 78(3):160-65.

2. Corey L, Adams HG, Brown ZA, et al. Genital herpes simplex virus infections: clinical manifestations, course and complications. Ann Intern Med 1983; 98:958-72.

3. Birch CJ, Druce JD, Catton MC, Macgregor L, Read T. Detection of varicella zoster virus in genital specimens using a multiplex polymerase chain reaction. Sex Transm Infect 2003 Aug; 79(4):298-300.

4. Scoular A, Gillespie G, Carman WF. Polymerase chain reaction for diagnosis of genital herpes in a genitourinary medicine clinic. Sex Transm Infect 2002 Feb; 78(1):21-5.

5. Marshall DS, Linfert DR, Draghi ABS, et al. Indentification of herpes simplex virus genital infection: comparison of a multiplex PCR assay and traditional virus isolation techniques. Modern Pathology 2001; 14:152-6.

about SDI | newsletters | grants | publications | literature reviews

WHO Home - WHO Search - TDR Home - SDI Home - SDI Contact us
(c) WHO/OMS 2001