Causative Agents
In 2009, the top 5 sexually-transmitted infections (STIs) diagnosed in Singapore were: Chlamydia trachomatis (infection of the urethra, cervix, pharynx and rectum), Neisseria gonorrhoeae (infection of the urethra, cervix, pharynx and rectum), non- gonococcal urethritis (NGU), herpes simplex virus (HSV): types 1 and 2 (ano- genital herpes), and human papilloma virus (HPV) (ano-genital warts). Other important STIs are Treponema pallidum (syphilis), Trichomonas vaginalis (trichomoniasis), and human immunodeficiency virus infection (HIV).
Incubation Period
Chlamydia : 5 - 14 days
Gonorrhoea : 3 - 5 days
Ano-genital herpes : 2 - 14 days
Ano-genital warts :1- 6 months (mean 3 months)
Syphilis : 10 - 90 days (mean 21 days)
Trichomoniasis : a few days
HIV : mean of 1 month to acute HIV infection, mean of 5 to 8 years to AIDS if untreated
Infectious Period
Gonorrhoea, chlamydia : active infection, symptomatic or asymptomatic Ano-genital herpes : presence of vesicles and erosions; asymptomatic
viral shedding is also an important route of transmission
Ano-genital warts : higher with presence of active lesions;
subclinical infections common
Syphilis : during primary and secondary stages
Trichomoniasis : active infection, symptomatic or asymptomatic
HIV infection : infectious from early on till demise if untreated