Prevalence of herpes simplex virus infection in patients suspected of genital herpes; and virus typing by type specific fluorescent monoclonal antibodies.

During the period between April 1994 and February 1996, a total of 154 female patients who attended the Clinic of Female Sexually Transmitted Diseases, Siriraj Hospital with clinical symptoms suspected of genital herpes were investigated for herpes simplex virus (HSV) infection by the virus isolation method in Vero cell cultures. Swabs from external genital lesions and the cervix from each patient were collected separately and used as the clinical specimens for isolation of HSV. The virus isolates were identified by indirect immunofluorescence (IIF) staining of the infected cell cultures using polyclonal HSV-2 specific antiserum which was reactive to common HSV antigens for both types of viruses. Typing of HSV was performed by direct IF using monoclonal antibody specific to HSV-1 or HSV-2. HSV was isolated from 78.6 per cent (121 of 154) of the cases studied; and among the infected cases, there were 47.9 per cent (58 of 121) in whom the infection involved both external genital lesions and cervixes, and 50.4 per cent (61) in whom the infection was limited to external genital lesions only. There were 2 cases (1.7%) in whom HSV was isolated from cervixes but not external genital lesions. Seventy-five HSV isolates were further subjected to typing. The present study showed that HSV-1 was accounted for 18.7 per cent (14 isolates), while HSV-2 took the remaining part of 81.3 per cent (61 isolates). The data demonstrated an increase in the prevalence of HSV-1 in genital herpes in our people.