Sexually transmitted diseases

Sexually transmitted diseases (STD) are a special category of direct-contact diseases. This mode of transmission is used by certain pathogens because they are specific for the urogenital system or because the transmission of bodily fluids facilitates entry into a new host. STDs are commonly caused by bacteria and viruses.

STDs in approximate order of most to least common

Disease Pathogen   U.S. Incidence (prevalence)
Genital warts HPV Virus 14.1 million (+79 million)
Chlamydia Chlamydia trachomatis Bacteria 2.86 million (+1.57 million)
Hepatitis Hepatitis B, C, D viruses Virus 1.5 million
Trichomoniasis Trichomonas vaginalis Protozoa 1.09 million (+3.7 million)
Gonorrhea Neisseria gonorrhoeae Bacteria 820,000
Herpes HSV-2 Virus 776,000 (+24 million)
Syphilis Treponema pallidum Bacteria 55,000 (+117,000)
AIDS HIV Virus 41,000 (+900,000)
Mpox Monkeypox virus Virus 29,000
LGV Chlamydia trachomatis Bacteria 300
Granuloma inguinale Klebsiella granulomatis Bacteria 272
Chancroid Haemophilus ducreyi Bacteria 143
Molluscum contagiosum poxvirus Virus common
T-cell lymphoma HTLV Virus rare
CMV inclusion disease CMV Virus ?
Zika infection Zika virus Virus rare