source: Novan’s notes, by George Novan, MD, and Joanna Breems, MD
Last update: September 2023
The terms STIs (sexually transmitted infections) and STDs (sexually transmitted diseases) are nterchangeable. However, more authors now favor using STI because not all “infections” are manifest as “disease”—that is, they are not clinically evident or symptomatic.
A note on terminology. One preventative method that applies to all STIs discussed here is “safer sex” which refers to risk-reduction methods that persons can take to reduce the chances of acquiring or transmitting an STI. While risk-reduction will be different for each person’s circumstance, in general, this refers to: use of barrier methods (condoms – male, female, oral), sharing of sexual health history between new partners, avoiding intoxication with drugs/alcohol, avoid douching after sex for females, regular self-exam and STI screens, and exploring sexual activities other than vaginal, anal, and oral sex that do not involve exchange of body fluids.
Definition of Sexually Transmitted Infections
STIs are Infections transmitted through (typically) sexual acts involving contact of skin/mucosal surfaces of the penis, vagina, rectum and oropharynx or exchange of body fluids at these sites.
STI syndromes and associated pathogens
SYNDROME ORGANISM
GENITAL ULCERS
Genital herpes Herpes simplex
Syphilis Treponema pallidum
Chancroid Haemophilus ducreyi
Lymphogranuloma venereum Chlamydia trachomatis serovar L1-L3
Granuloma inguinale (Donovanosis) Klebsiella granulomatis
EPITHELIAL CELL INFECTIONS
Genital warts Human papillomavirus
Cervical neoplasia Human papillomavirus types 16 and 18
URETHRITIS
Gonococcal Neisseria gonorrhoeae
Nongonococcal Chlamydia trachomatis
Trichomonas vaginalis
Herpes simplex (primary infection)
FEMALE GENITAL DISCHARGE
Cervicitis Neisseria gonorrhoeae
Chlamydia trachomatis
Trichomonas vaginalis
Herpes simplex
Bacterial vaginosis Gardnerella vaginalis, anaerobes
Vaginitis Trichomonas vaginalis
Candida albicans
Modified from Table 269-1. Swygard H, Cohen MS. Approach to the Patient with a Sexually Transmitted Infection. In: Goldman L, Schafer AI, eds. Goldman-
Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020. pp. 1841-1845.e2
STIs caused by ectoparasites that are not covered in the large-group teaching sessions are: genital scabies and pubic lice.
Genital Herpes: Herpes Simplex Virus (HSV-2, HSV-1)
see session on Herpes Viruses in FMS502 for review here.
Table: HSV-1 and HSV-2
Designation Common Name Transmission Primary Infection
Site
Disease Latent Infection
Site
HHV-1 Herpes simplex
virus 1 (HSV-1)
Close contact Mucoepithelial
cells
Oral (fever blisters),
ocular lesions;
encephalitis
Nerve ganglia
HHV-2 Herpes simplex
virus 2 (HSV-2)
Close contact
Sexual
transmission
Mucoepithelial
cells
Genital, anal lesions;
severe neonatal
infections; meningitis
Nerve ganglia