Genital warts in females Gall Figure 1 Location of genital warts in women now the most commonly diagnosed STD in genitourinary medicine clinics10. RISK FACTORS ASSOCIATED WITH HUMAN PAPILLOMAVIRUS INFECTIONS Two factors that clearly influence the incidence of genital HPV infection are age and sexual behavior. As is the case with other sexually transmitted infec- tions, prevalence is reported to be highest in sexually active young adults between 18 and 25 years of age8. Sexual behavior also has an influence on the potential risk of being infected with HPV. Women with five or more partners in the previous 5 years are over seven times more likely to have an episode of genital warts and are over 12 times more likely to have recurrent genital warts, compared with women with one sexual partner in this time11. Other risk factors reported in this study were a history of any other STDs, a history of oral herpes or a history of allergies11. There is conflicting evidence about whether smoking and use of oral contraceptives are also risk factors for genital warts11–15. Human immunodeficiency virus (HIV) infec- tion is an additional determining factor for infec- tion with other STDs, including genital warts. In one study, HIV-positive women were found to be over six times more likely to have genital warts, and over three times more likely to test positive for oncogenic HPV than HIV-negative women16. This study reported an annual incidence rate for genital warts in HIV-positive women of 11.4%, compared with 1.4% in HIV-negative women16. Furthermore, the host’s immune status is also a factor that is important in controlling HPV infec- tions and the development of HPV lesions such as genital warts. This is supported by the observation that patients who are immunosuppressed have an increased incidence of HPV-associated lesions17. Activation of the specific humoral and cellular immunity pathways is reported to be important in HPV-infected individuals for spontaneous regres- sion of genital warts18. HUMAN PAPILLOMAVIRUS AND ANOGENITAL CANCER Although genital warts are considered to be a benign condition, an association between HPV infection and squamous cell carcinoma (SCC) of the anogenital tract has been identified15. Cervical cancer is the most common type of anogenital cancer; however, vulvar, vaginal and anal cancer are also associated with HPV19. HPV prevalence, in particular ‘high risk’ HPV types 16 and 18, is greater than 99% in cervical carcinomas20. Other HPV types that are associated with anogenital cancer are HPV 31, 33, 35 and 45 (Table 1)21. The increasing incidence of cervical intra- epithelial neoplasias (CIN) in younger women22 is of concern because of their malignant potential. For example, over 30% of CIN3 lesions progress to SCC within 1–10 years22. The progression from low-grade lesion to high-grade lesion or SCC is also reported to occur in approximately a third of cases22. The outcome of low-grade cervical neoplasia is influenced by a number of factors, including the oncogenicity of infecting HPV type, sexual behavior, infection of the cervical epithelium with other viral/bacterial agents, ciga- rette smoking, oral contraceptive usage and host immunosuppression22. TRANSMISSION OF GENITAL WARTS An important issue for women with genital warts is the concern about transmission of HPV and genital warts to their sexual partners. Transmission is believed to be predominantly through sexual intercourse, as genital HPV is absent in the major- ity of women who have not had sexual intercourse. 150 INFECTIOUS DISEASES IN OBSTETRICS AND GYNECOLOGY