List of Major sexually transmitted diseases and their causative agents

The number of sexually transmitted microorganisms (eg, bacteria, virus, fungi and parasites) and the spectrum of clinical syndromes or diseases associated with these agents are expanding with the nature of changing sexual orientations of people and increasing number of immunosuppressive population (people with HIV/AIDS, under immunosuppressive therapy, cancer conditions) etc.

While developed countries have access to testing methods both at medical institutions and via at home STD test options with lab processing of the results, many populations in developing countries do not have access to STI information, testing or preventative measures.  Due to the asymptomatic nature of many STDs, those without this knowledge and access to medical testing and care, are at higher risk of contracting and transmitting these infections.

Multiple pathogens can cause one particular disease e.g. vaginitis can be caused by Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis etc.

This blog post lists some of the selected sexually transmitted diseases and pathogen mostly associated with that particular disease.

1. Acquired Immunodeficiency Syndrome (AIDS): Human immunodeficiency virus (HIV)
2. Bacterial vaginosis: Gardnerella vaginalis
3. Chancroid: Haemophilus ducreyi
4. Chlamydia trachomatis infections (such as cervicitis, urethritis, prepubertal vaginitis, proctitis, endometritis etc) : Chlamydia trachomatis
5. Chlamydial lymphogranuloma: Chlamydia trachomatis serovars L1, L2 and L3
6. Genital Herpes: Herpes Simplex Virus type 2
7. Gonorrhea: Neisseria gonorrhoeae
8. Lymphogranuloma venereum: C. trachomatis
9. Neonatal sepsis and meningitis: Streptococcus agalactiae
10. Nongonococcal urethritis: C. trachomatis, Ureaplasma urealyticum or Trichomonas vaginalis
11. Pelvic inflammatory disease: N. gonorrhoeae or C. trachomatis
12. Syphilis: Treponema pallidum
13. Trichomoniasis: Trichomonas vaginalis
14. Vulvovaginal candidiasis: Candida albicans

Testing of Sexually Transmitted Infections (STIs)

Laboratory diagnosis of some STIs require expensive technologies or the facilities of a specialist laboratory while others can be diagnosed at home or at district/general laboratories.

STIs like gonorrhoea, syphilis, trichomoniasis, candidiasis, G.vaginalis bacterial vaginosis etc can be diagnosed using appropriate microscopy and staining techniques. Diseases like gonorrhoea, chancroid can be diagnosed by culture using selective enriched medium. Immunological methods (e.g. ELISA, ICT based tests) are now available for the diagnosis of chlamydial infections, HIV, Genital herpes infection, syphilis etc.  PCR and molecular technologies have also been developed to diagnose some STIs like HIV.