Sexually Transmitted Diseases

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Introduction

Sexually transmitted infections are infections primarily spread through sexual contact, including vaginal, anal, and oral intercourse. These infections may be caused by:

  • Bacteria
  • Viruses
  • Fungi
  • Parasites

Sexually transmitted diseases (STDs), also known as sexually transmitted infections (STIs), remain a major global public health problem affecting millions of people each year.

Many STDs may remain asymptomatic, especially during early stages, leading to continued transmission and delayed treatment. If untreated, they can cause serious complications such as:

  • Infertility
  • Pelvic inflammatory disease
  • Pregnancy complications
  • Cancer
  • Neurological disorders
  • Increased risk of HIV transmission

Causative Organisms

Bacterial STDs

Disease Organism
Syphilis Treponema pallidum
Gonorrhea Neisseria gonorrhoeae
Chlamydia Chlamydia trachomatis

Viral STDs

Disease Virus
Human Immunodeficiency Virus Infection HIV
Genital Herpes HSV-2 / HSV-1
Human Papillomavirus Infection HPV
Hepatitis B HBV

Parasitic and Fungal STDs

Disease Organism
Trichomoniasis Trichomonas vaginalis
Candidiasis Candida albicans

Modes of Transmission

STDs spread through:

  • Unprotected sexual intercourse
  • Multiple sexual partners
  • Infected blood transfusion
  • Needle sharing
  • Mother-to-child transmission during pregnancy or delivery

Risk factors include:

  • Poor sexual hygiene
  • Lack of awareness
  • Early sexual activity
  • Immunosuppression

Clinical Features

Symptoms vary depending on the infection.

Common manifestations include:

  • Genital ulcers or sores
  • Abnormal genital discharge
  • Burning micturition
  • Lower abdominal pain
  • Rash involving palms and soles (syphilis)
  • Itching and irritation
  • Fever and malaise
  • Pain during intercourse

Some individuals remain completely asymptomatic.

Sexually Transmitted Diseases

1. Syphilis

  • Caused by Treponema pallidum
  • Characterized by:
    • Painless chancre
    • Rash involving palms and soles
    • Latent and tertiary stages

Diagnosis

  • VDRL
  • TPHA
  • FTA-ABS

Treatment

  • Penicillin G

2. Gonorrhea

  • Caused by Neisseria gonorrhoeae
  • Features:
    • Purulent discharge
    • Dysuria
    • Cervicitis

Diagnosis

  • Gram stain
  • Culture
  • NAAT

Treatment

  • Ceftriaxone

3. Chlamydia

  • Caused by Chlamydia trachomatis
  • Often asymptomatic

Features

  • Urethritis
  • Cervicitis
  • Pelvic inflammatory disease

Treatment

  • Azithromycin or doxycycline

4. Genital Herpes

  • Caused by HSV-2 mainly
  • Painful vesicular genital lesions
  • Recurrent infection common

Treatment

  • Acyclovir

5. HIV/AIDS

  • Caused by Human Immunodeficiency Virus (HIV)
  • Attacks CD4 T lymphocytes

Features

  • Immunodeficiency
  • Opportunistic infections
  • Weight loss

Treatment

  • Antiretroviral therapy (ART)

Laboratory Diagnosis

Accurate laboratory diagnosis is important for early treatment, prevention of transmission, and reduction of complications.

1. Specimen Collection

Depending on the disease, specimens include:

  • Urethral swab
  • Cervical swab
  • Vaginal swab
  • Blood sample
  • Urine sample
  • Lesion or ulcer exudate

2. Microscopy

Used for rapid preliminary diagnosis.

Examples:

  • Gram stain for Gonorrhea
    • Shows intracellular Gram-negative diplococci
  • Dark-field microscopy for Syphilis
    • Demonstrates motile spirochetes

3. Culture

Useful for bacterial infections.

Common culture methods:

  • Thayer–Martin medium → Neisseria gonorrhoeae
  • Viral culture for herpes (less commonly used now)

4. Serological Tests

Important examples:

  • VDRL / RPR → screening for syphilis
  • TPHA / FTA-ABS → confirmatory tests for syphilis
  • ELISA → HIV and hepatitis detection

5. Molecular Tests

NAAT / PCR

Highly sensitive and specific.

Used for:

  • Gonorrhea
  • Chlamydia
  • HIV
  • Herpes virus infections

6. Rapid Diagnostic Tests

Rapid kits are available for:

  • HIV
  • Syphilis
  • Hepatitis B

Useful in screening programs and emergency settings.

Complications of STDs

Untreated STDs can lead to serious local and systemic complications.

1. Reproductive Complications

  • Infertility
  • Pelvic inflammatory disease (PID)
  • Epididymitis
  • Chronic pelvic pain
  • Ectopic pregnancy

2. Pregnancy and Neonatal Complications

  • Congenital infections
  • Miscarriage
  • Stillbirth
  • Premature delivery

Example:

  • Congenital syphilis
  • Neonatal gonococcal conjunctivitis

3. Malignancy

  • Persistent Human Papillomavirus Infection may lead to:
    • Cervical cancer
    • Anal cancer
    • Penile cancer

4. Neurological and Cardiovascular Complications

Seen especially in untreated syphilis:

  • Neurosyphilis
  • Dementia
  • Aortic aneurysm

5. Increased HIV Transmission

The presence of genital ulcers and inflammation increases susceptibility to HIV infection.

Prevention of STDs

Prevention is the most effective strategy in controlling STDs.

1. Safe Sexual Practices

  • Consistent and correct condom use
  • Avoid multiple sexual partners
  • Mutual monogamous relationship

2. Health Education

  • Public awareness regarding transmission and prevention
  • Sex education programs

3. Early Diagnosis and Treatment

  • Prompt treatment reduces complications and spread
  • Simultaneous treatment of sexual partners

4. Screening Programs

Routine screening for:

  • HIV
  • Syphilis
  • Hepatitis B
  • Chlamydia in high-risk groups

5. Vaccination

Vaccines available for:

  • Human Papillomavirus Infection
  • Hepatitis B

6. Avoid Sharing Needles

Important in prevention of:

  • HIV
  • Hepatitis B
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