STI: Infections of the Genital Tract Flashcards
Commensal micro-organism
A micro-organism that derives food or other benefits from another organism without hurting or helping it.
Pathogen
A micro-organism that can cause disease
Infection
The invasion of all or part of the body by a micro-organism
What is the difference between a clinical and sub-clinical infection?
- Clinical= symptoms
- Subclinical= no symptoms
Sexually transmissible microbe
- A virus, bacteria or protozoan which can be spread by sexual contact
- Can be commensal or pathogen
Sexually transmitted infection
An infection by a pathogen which is sexually transmissible and which is unlikely to be transmitted by non-sexual means
Sexually transmitted disease
A disorder of structure or function caused by a sexually transmitted pathogen
Give examples of venereal diseases and their causative agent.
- Syphilis (Treponema pallidum pallidum)
- Gonorrhoea (Neisseria gonorhoeae)
- Chancroid (Haemophilus ducreyi)
Give examples of sexually transmitted bacteria in the UK.
- Chlamydia trachomatis
- Klebsiella granulomatis
- Mycoplasma genitalium
Give examples of sexually transmitted viruses in the UK.
- HSV
- HIV
- HPV
- Molluscum contagiosum virus
Give examples of sexually transmitted parasites in the UK.
- Pthirus pubis
- Sarcoptes scabei
- Trichomonas vaginalis
Give examples of infection vs colonisations.
- Mycoplasma hominis
- Ureaplasma urealyticum
- Bacterial vaginosis
- Genital candidosis
What are the features of an STI?
- Transmissible (partner notification
- Asymptomatic (hard to eradicate, requires prevention)
- All manageable but not curable (treatment and prevention complications)
- Avoidable (primary prevention education)
Give examples of sexual contact.
Greatest risk of infection -Group sex -Anal sex -Vaginal sex -Oral sex -Touching someone else's genitals with yours -Mutual masturbation Least risk of infection
What conditions can be transmitted through genital contact alone?
- Pubic lice (Pthirus pubis)
- Scabies (Sarcoptes scabeii)
- Warts (human papilloma virus types 6 &11)
- Herpes (Herpes Simplex Virus types 1 & 2)
What condition is often transmitted through group sex?
Hepatitis C
Why are STIs important?
- Cause morbidity and mortality
- Drain on resources
- They’re common
What systemic symptoms can STIs present with?
- Fever
- Rash
- Lymphadenopathy
- Malaise
- Infertility
What are the possible complications of STIs?
- Cancer
- Adverse pregnancy outcomes
How can we tell if there is change in the number of cases of STIs?
- Average number of infections produced(Ro) is equal to the (likelihood of transmission) (rate of acquiring new partners) (duration of infectivity)
- If Ro >1 then epidemic is sustained, if <1 then epidemic reduced
What 3 things should parents know about preventing cervical cancer?
- HPV vaccination is the best way to prevent many types of cancer
- HPV vaccination is recommended at ages 11-12
- HPV vaccination is reducing HPV disease
How are people’s attitudes to sex changing?
- Increased numbers of partners/person
- Increased concurrent partners
- More people having anal sex
- More men reporting sex with men
- (Also increased condom usage).
Why is more STI testing occurring?
- Greater awareness
- More people asking for tests
- More clinicians considering STIs
What testing methods are used?
- Nucleic acid amplification testing
- Enzyme immunoassays for chlamydia
