How many STIs are there and what are their names?

The number of STIs (sexually transmitted infections) will vary depending on what is counted as an STI and whether sexually transmissible infections are counted. The Medical Institute uses a list of STIs that is adapted from chapter headings in a standard STI textbook1. This list, which appears below in alphabetical order, has 27 different infections.

Bacterial:
1. bacterial vaginosis
2. chancroid
3. chlamydia
4. donovanosis
5. gonorrhea
6. lymphogranuloma venereum
7. mycoplasma, genital
8. syphilis
9. treponematosis, endemic

Ectoparasitic:
10. lice, pubic
11. scabies
12. candidiasis, vulvovaginal

Protozoal:
13. amebiasis
14. cryptosporidium
15. giardiasis
16. trichomoniasis

Viral:
17. cytomegalovirus
18. Epstein Barr virus
19. hepatitis A
20. hepatitis B
21. hepatitis C
22. hepaptitis D
23. herpes simplex virus (HSV-1 and HSV-2)
24. human immunodeficiency virus (HIV)
25. human papillomavirus (HPV)
26. human T-cell lymphotropic virus (HTLV-1)
27. molluscum contagiosum

Reference:
1. Holmes KK, Sparling PF, Stamm WE, et al. Sexually Transmitted Diseases, 4th Ed. New York, NY: McGraw Hill Medical; 2008.

Reviewed: June 29, 2012.