STIs A–Z
Overviews for every condition we screen for — organized by name and category.
This content is for general educational purposes and is not a substitute for diagnosis, treatment, or personalized medical advice from a qualified healthcare professional.
Chlamydia
Chlamydia is a common bacterial STI caused by Chlamydia trachomatis. Many people with chlamydia have no symptoms, which is why testing matters.
Gonorrhea
Gonorrhea is a bacterial STI caused by Neisseria gonorrhoeae. It can infect the genitals, rectum, and throat.
Hepatitis B
Hepatitis B is a viral infection affecting the liver. Vaccines are widely available.
Hepatitis C
Hepatitis C is a viral infection affecting the liver. Modern treatment can cure most cases.
Herpes (HSV-1 / HSV-2)
Herpes simplex virus can cause oral or genital sores. Many people carry the virus without symptoms.
HIV
HIV (human immunodeficiency virus) affects the immune system. Modern testing and treatment make HIV highly manageable when identified early.
HPV (Human Papillomavirus)
HPV is a common viral infection with many strains. Vaccines and screening are available.
Mycoplasma genitalium
Mycoplasma genitalium is an increasingly recognized bacterial STI.
Syphilis
Syphilis is a bacterial STI that progresses in stages. Early testing and treatment are effective.
Trichomoniasis
Trichomoniasis is a common parasitic infection caused by Trichomonas vaginalis.