Background:
Genital herpes increases the transmission of HIV. During a syphilis epidemic, it is likely that testing for herpes increases due to increased evaluation of genital ulcer disease. HSV1 can be clinically difficult to distinguish from HSV2, but has implications for patient counseling.

Objective:
To describe HSV culture testing at San Francisco's STD clinic from 1995-2005, and to compare the number and proportion of all HSV and HSV1 positive cultures at the beginning and end of this period.

Method:
Total HSV cultures performed at the STD clinic, and the results by type were assessed from 1995-2005. The proportion of positive HSV and HSV1 cultures were compared for two years: 1995 and 2005

Result:
From 1995-2005, 6128 HSV cultures were performed. A total of 303 tests were sent in 1995, with gradual increases until 2000 (473 cultures). Testing then markedly increased for the next four years, with a peak of 837 cultures in 2004. Of all cultures performed in 1995, 164 (54%) were HSV positive, while in 2005 this number was 235 (35%) (p<0.001). The proportion of HSV positive specimens that were HSV1 rather than HSV2 increased from 20.7% (34/165) in 1995 to 37.0% (87/235) in 2005 (p<0.001).

Conclusion:
HSV culture testing greatly increased during a period of epidemic syphilis in San Francisco. While the proportion of positive tests decreased in 2005 compared to 1995, the absolute number of positive cultures increased. The proportion of HSV1 positive cultures was greater in 2005 compared to 1995.

Implications:
Increased testing identified more cases of HSV, and these individuals must be counseled about their increased HIV transmission or acquisition risk. An increasing proportion of HSV genital ulcer disease in our clinic is caused by HSV1. We anticipate a newly implemented protocol for HSV PCR, replacing culture, will further improve our diagnostic ability.