Sexually transmitted infections (STIs) may be caused by bacteria, viruses or parsite acquired through sexual contact.
Sexually transmitted infections (STIs) are those caused by the introduction of infectious micro-organisms during sexual intercourse, anal sex, oral sex, and/or other forms of sexual intimacy where exchange of fluids (semen, vaginal fluid, blood, other body fluids) containing infectious organisms can occur.
The World Health Organization (WHO) estimated in 2003 that more than 330,000,000 curable sexually transmitted infections occur each year worldwide. In addition, 40,000,000 new HIV/AIDS infection occur each year worldwide. In the U.S. alone, approximately 19,000,000 new sexually transmitted infections occur each year.
Sexually transmitted infections are caused by a variety of organisms: viruses, bacteria and parasites.
Viruses:
- human papillomavirus [HPV],
- herpes simplex virus [HSV-2 (genital herpes), HSV-1],
- hepatitis B virus [HBV]
- hepatitis C virus [HCV]
- human immunodeficiency virus [HIV/AIDS].
Bacteria:
- Chlamydia trachomatis [chlamydia],
- Neisseria gonorrhoeae [gonorrhea],
- Treponema pallidum [syphilis],
- bacterial vaginosis [BV]),
- Haemophilus ducreyi [chancroid],
- Chlamydia trachomatis (serovars L1, L2, or L3) [lymphogranuloma venereum],
- Calymmatobacterium granulomatis [granuloma inguinale/donovanosis].
Parasites:
- Trichomonas vaginalis [trichomoniasis],
- Pediculosis pubis [pubic lice],
- Sarcoptes scabiei [scabies].
Frequency of sexually transmitted infections
The World Health Organization (WHO) estimated in 2003 that 333,000,000 curable sexually transmitted infections occur each year worldwide, with an additional 40,000,000 HIV/AIDS infections.
In the United States, 19,000,000 sexually transmitted infections occur each year, with almost half of them in the 15 to 24 age group.
- 2,800,000 million new cases of chlamydia each year (less than half of which are reported),
- 718,000 new cases of gonorrhea each year (only about half of which are reported),
- > 8,700 new cases of syphilis,
- > 45,000,000 people (ages 12 and older), or 1 in 5 adolescents and adults have had genital herpes,
- 20,000,000 people infected with HPV with 6,200,000 new infections each year (at least 50% of sexually active men and women acquire genital HPV infection during their lifetime: > 80% of women will have had HPV infection by age 50),
- 7,400,000 new cases of trichomoniasis each year,
- 1 in 20 people have been infected with HBV during their lifetime (approximately 60,000 new cases in 2004),
- > 1,000,000 people infected with HIV with > 40,000 new cases each year.
Symptoms of sexually transmitted infection:
- unusual vaginal discharge,
- penis discharge,
- burning or painful urination,
- burning or pain following sex,
- genital or anal sores,
- genital or anal itching,
- rash,
- flu-like symptoms (e.g. HBV, HCV, HIV),
- swollen glands in groin area.
Many sexually transmitted infections are easily treated, and treatment is organism-specific.
Read more about sexually transmitted diseases:
STI: Risk factors, prevention and treatment
Human papillomavirus: The Silent Infection
Trichomonas vaginalis Parasite
Bloodborne Pathogens: Associated Risks
PID: Risk Factors and Prevention
Pelvic Inflammatory Disease: What is it?
