Important: STDs/STIs are extremely common and many people have no symptoms at all. Testing, treatment, vaccines, and safer sex practices help protect your health and future fertility.

Quick Jump — 20 Common STDs/STIs

• Chlamydia
• Gonorrhea
• Syphilis
• HIV
• HPV
• Genital Herpes (HSV)
• Hepatitis B
• Hepatitis C
• Trichomoniasis
• Pubic Lice
• Scabies
• Molluscum Contagiosum
• Mycoplasma Genitalium
• Chancroid
• LGV
• Granuloma Inguinale
• Ureaplasma
• Pelvic Inflammatory Disease
• Bacterial Vaginosis
• Yeast Infection

• Many STIs have NO symptoms.
• Condoms reduce risk but do not prevent every STI.
• Vaccines exist for HPV and Hepatitis B.
• Early treatment helps prevent complications.
• Testing is part of normal healthcare.
• Untreated STIs can affect fertility, pregnancy, and long-term health.

CDC – STI Prevention

Chlamydia is one of the most common bacterial STIs, especially in teens and young adults.

• Symptoms: burning urination, discharge, pelvic pain, or no symptoms.
• Spread: vaginal, anal, or oral sex.
• Treatment: antibiotics.
• Risk: untreated infections can affect fertility.

CDC – Chlamydia
MedlinePlus – Chlamydia

Gonorrhea is a bacterial STI that can infect the genitals, throat, and rectum.

• Symptoms: discharge, burning urination, pelvic pain, sore throat.
• Treatment: antibiotics.
• Important: antibiotic-resistant gonorrhea is increasing.

CDC – Gonorrhea
Mayo Clinic – Gonorrhea

Syphilis is a bacterial infection that develops in stages and can become very serious if untreated.

• Early sign: painless sore (chancre).
• Later symptoms: rash, fever, nerve damage.
• Treatment: penicillin antibiotics.

CDC – Syphilis
NHS – Syphilis

HIV attacks the immune system. Treatment allows many people with HIV to live long healthy lives.

• Symptoms: flu-like illness early on, or no symptoms.
• Treatment: antiretroviral therapy (ART).
• Prevention: condoms, testing, PrEP.

CDC – HIV
NIH HIV Info

HPV is the most common STI in the world.

• Symptoms: often none.
• Can cause: genital warts and some cancers.
• Protection: HPV vaccine.

CDC – HPV
FDA – HPV Vaccine

Herpes is a viral STI that causes outbreaks of sores or blisters.

• Symptoms: painful blisters or sores.
• Spread: skin-to-skin contact.
• Treatment: antiviral medicine helps reduce outbreaks.

CDC – Herpes
WebMD – Genital Herpes

Hepatitis B is a viral infection affecting the liver.

• Symptoms: fatigue, jaundice, nausea.
• Spread: blood, semen, body fluids.
• Prevention: vaccine.

CDC – Hepatitis B
MedlinePlus – Hepatitis B

Hepatitis C mainly spreads through blood contact and can damage the liver.

• Symptoms: often none for years.
• Treatment: antiviral medications can cure many cases.

CDC – Hepatitis C
Mayo Clinic – Hepatitis C

Trichomoniasis is caused by a parasite.

• Symptoms: itching, discharge, odor, burning.
• Treatment: prescription antibiotics.

CDC – Trichomoniasis
MedlinePlus – Trichomoniasis

Pubic lice are tiny insects that attach to pubic hair.

• Symptoms: itching and visible lice or eggs.
• Treatment: medicated lotions or shampoos.

CDC – Pubic Lice

Scabies is caused by tiny mites that burrow into the skin.

• Symptoms: intense itching and rash.
• Spread: close skin contact.
• Treatment: prescription creams.

CDC – Scabies

Molluscum contagiosum is a viral skin infection.

• Symptoms: small raised bumps.
• Spread: skin contact.
• Treatment: sometimes resolves on its own.

CDC – Molluscum Contagiosum

Mycoplasma genitalium is a bacterial STI linked to urethritis and pelvic infections.

• Symptoms: burning, discharge, pelvic pain.
• Treatment: specific antibiotics.

CDC – Mycoplasma Genitalium

Chancroid is a bacterial STI that causes painful sores.

• Symptoms: genital ulcers and swollen lymph nodes.
• Treatment: antibiotics.

CDC – Chancroid

LGV is a rare type of chlamydia infection.

• Symptoms: sores, swollen lymph nodes, rectal symptoms.
• Treatment: antibiotics.

CDC – LGV

This rare bacterial STI causes progressive genital sores.

• Symptoms: painless beefy-red sores.
• Treatment: antibiotics.

CDC – Donovanosis

Ureaplasma bacteria may sometimes contribute to urinary or genital symptoms.

• Symptoms: irritation, discharge, pelvic discomfort.
• Treatment: antibiotics when needed.

MedlinePlus

PID is a serious infection of female reproductive organs, often caused by untreated STIs.

• Symptoms: pelvic pain, fever, discharge.
• Risk: infertility if untreated.

CDC – PID
Mayo Clinic – PID

BV is caused by an imbalance of normal vaginal bacteria.

• Symptoms: odor, discharge, irritation.
• Treatment: antibiotics.

CDC – Bacterial Vaginosis

Yeast infections are fungal infections that are not always sexually transmitted but can occur after sex or antibiotic use.

• Symptoms: itching, thick white discharge, irritation.
• Treatment: antifungal medication.

MedlinePlus – Yeast Infections

1. What does STI stand for?
   Answer: Sexually Transmitted Infection.
2. Can someone have an STI without symptoms?
   Answer: Yes.
3. Which STI is the most common worldwide?
   Answer: HPV.
4. What protects against many STIs?
   Answer: Condoms.
5. Which STI can be prevented with a vaccine?
   Answer: HPV and Hepatitis B.
6. What bacteria causes chlamydia?
   Answer: Chlamydia trachomatis.
7. What STI can cause genital warts?
   Answer: HPV.
8. Can HIV be treated?
   Answer: Yes.
9. What organ does hepatitis affect?
   Answer: The liver.
10. What STI commonly causes painful blisters?
    Answer: Herpes.
11. Can untreated STIs affect fertility?
    Answer: Yes.
12. What parasite causes trichomoniasis?
    Answer: Trichomonas vaginalis.
13. What STI may cause a painless sore?
    Answer: Syphilis.
14. Can oral sex spread STIs?
    Answer: Yes.
15. What does PID stand for?
    Answer: Pelvic Inflammatory Disease.
16. Can condoms reduce HIV risk?
    Answer: Yes.
17. What STI is known as “crabs”?
    Answer: Pubic lice.
18. Can gonorrhea infect the throat?
    Answer: Yes.
19. What STI attacks the immune system?
    Answer: HIV.
20. Can bacterial STIs usually be cured?
    Answer: Many can with antibiotics.
21. What STI is caused by mites?
    Answer: Scabies.
22. What STI often has no symptoms in women?
    Answer: Chlamydia.
23. What medicine type treats fungal infections?
    Answer: Antifungal medication.
24. Can teens get STIs?
    Answer: Yes.
25. Should sexual partners be tested too?
    Answer: Yes.
26. Can STI testing be part of routine healthcare?
    Answer: Yes.
27. What is PrEP used for?
    Answer: HIV prevention.
28. What STI can increase cancer risk?
    Answer: HPV.
29. Can early treatment help prevent complications?
    Answer: Yes.
30. Is getting tested something to feel ashamed about?
    Answer: No.

Trusted STD/STI Resources

CDC STD Resource Center
MedlinePlus – STDs
Mayo Clinic
WebMD Sexual Health
NHS Sexual Health
National Institutes of Health (NIH)
FDA