Prevalence and typing of human papilloma virus (HPV) among female sex workers and outpatient women in southern Thailand

Abstract

Thai sex workers (SW) have high rates of sexually transmitted infections (STIs); however, detection and treatment is often complicated by accessibility to sensitive and accurate diagnostic tests. Self-sampling of women combined with molecular amplification techniques could help in accurate diagnosis, treatment and follow-up of such women. Detection of persistent high-risk human papilloma virus (HPV) in such populations could also be beneficial in identifying women who may need more frequent follow-up for cervical cytology screening. The current study aimed to examine the prevalence of HPV in this population and compare this with the lower-risk outpatient women (OPW) in Thailand. Four hundred and thirty OPW and 524 Thai SW were sampled by a self-administered tampon collection. Cells were extracted from tampons and, subsequently, women underwent routine vaginal examination for detection of other STIs. Detection of HPV was performed by polymerase chain reaction (PCR) using the L1 consensus primers, followed by L1 consensus probe using an in-house PCR-enzyme-linked immunosorbent assay (ELISA). All positive samples were typed using PCR-ELISA and type-specific oligonucleotide probes. Overall, HPV was detected in 20/430 (4.6%) and 120/524 (22.9%) in OPW and SW respectively. Over 98% of samples produced a beta-globin signal, indicating adequately collected samples. Human papilloma virus typing probes detected HPV16 or 18 in 14% and 26% of the positive samples from OPW and SW respectively. HPV31, 33, 35 or 39 were detected in 19% and 12% and HPV45, 51 or 52 in 9.5% and 4% of positive OPW and SW patients respectively. Low risk HPV6 or 11 were detected in 1% and 4.9% of OPW and SW respectively. There was a significantly higher HPV prevalence in Thai SW than OPW, with the majority (21%) of positive samples containing the oncogenic HPV16 or 18 DNA. The results indicate that PCR could serve as a rapid and easy method for identification of women who require more frequent screening for cervical cancer.