Public Health

• Sexually transmissible infections (STIs)

  Infections that are transmitted via sexual contact including vaginal, oral and anal sex
• Bacteria, viruses and parasites that can be transmitted through sexual contact


  • Over 30 different (some listed on next slide)
• Commonest curable STIs


  • Chlamydia
  • Gonorrhoea
  • Trichomoniasis
  • Syphilis
• Commonest viral STIs


  • Hepatitis B
  • Herpes simplex virus
  • HIV
  • Human papillomavirus (HPV)
• STIs can also be spread via blood or blood products (Hep B and HIV) and some from mother to child during pregnancy and childbirth (syphilis, hepatitis B, HIV, chlamydia, gonorrhoea, herpes and HPV)
• STIs are a major cause for concern in Australia
• Complications of untreated STIs

  • In adults: Tubal infertility, pelvic inflammatory disease, ectopic pregnancy, epididymo-orchitis
  • In infants: Congenital syphilis, neonatal sepsis
• STIs increase the risk of HIV transmission


  As they disrupt the genital mucosal membrane through ulceration and inflammation
• A majority of STIs are asymptomatic which reinforces the need for early diagnosis and treatment
• Bacterial STI infections can infect the prostate, urethra and testes in men, and the cervix, uterus and pelvis in women
• Bacterial STI infections are largely asymptomatic
• If left untreated, bacterial STI infections can lead to inflammation of the upper genital tract, infertility in men, pelvic inflammatory disease, ectopic pregnancies, chronic pelvic pain and infertility in women
• Bacterial STI infections can be treated with antibiotics
• Chlamydia is the most frequently reported notifiable STI in Australia in 2022, with 93,777 new notifications, 70% of which were in 15-29 year olds and half in females
• Gonorrhoea


  Highly infectious bacterial STI that can be asymptomatic, but common symptoms include penile discharge, burning urination and testicular swelling in men, and vaginal discharge, burning urination and bleeding between periods in women. Untreated can lead to infertility, but can be cured by antibiotics, though drug resistant strains are emerging.
• Syphilis


  Causes chancres (painless ulcers) on genitals, cervix and mouth, and consists of 3 stages (primary, secondary and tertiary) which can be asymptomatic (latent phase). If left untreated can lead to irreversible damage to the brain, spinal cord and other organs (tertiary syphilis), but responds to penicillin.
• Syphilis is a notifiable disease in Australia, with 6,036 new cases of infectious syphilis in 2022, the majority in males (82%)
• Monkeypox


  Until recently was not considered an STI, but is an endemic viral zoonotic disease (transmitted from animals to humans) in Central and West Africa, that has now caused a major outbreak outside of known endemic regions, with most cases in males between 18-44 years old.
• Groups at higher risk of STIs

  • Males: Gonorrhoea, syphilis
  • Adolescents & young people: 70% of chlamydia notifications in 15-29 year olds
  • Indigenous population: Higher notifications of chlamydia, gonorrhoea, syphilis
  • Those in rural vs metropolitan areas
• Behavioral determinants of STIs

  • Early sexual debut
  • Higher number of sexual partners
  • Concurrent (overlapping) and non-monogamous sex partners
  • Technology enabled social networking
  • Substance use and misuse
  • Experience of sexual and physical violence
  • Inconsistent condom use
• Social determinants of STIs

  • Income inequality and poverty
  • Education level
  • Discrimination and experienced stigma
  • Access to health services
  • Gender inequalities
• STIs are preventable, but prevention/control continue to fail worldwide and in Australia despite many interventions
• Strategies for prevention and control


  • Determine which populations are at greatest risk
  • Determine what behaviours or circumstances put these populations at risk
  • Determine the best approaches and interventions to break the chain of transmission
  • Prioritize, scale up and sustain the interventions
• Priority areas for action in Australia

  • Education and prevention
  • Testing and treatment
  • Equitable access and coordination of care
  • Workforce training and capacity building
  • Addressing stigma
  • Data, surveillance, research, evaluation