STIs Flashcards
Define commensal micro-organism
Micro-organism that derives food/benefits from another organism without harming or benefiting it
Define pathogen
A micro-organism that causes disease
Define infection
Invasion/multiplication of the body by an organism that is not usually found on it
Define sexually transmissible micro-organism
Virus, bacteria, parasite which is spread by means of sexual contact (can be commensal or pathogenic)
Define STI
An infection caused by a pathogen which is spread by sexual contact and is unlikely to be spread by other means
Define STD
Disease resulting from an STI e.g. genital warts, PID
What bacteria are considered STIs?
Neisseria gonorrhoea Chlamydia trachomatis Klebsiella granulomatis Mycoplasma genitalium Treponema pallidum
What viruses are considered STIs?
Molluscum contagiosum
HSV
HIV
HPV
What parasites are considered STIs?
Pthirus pubis
Sacroptes scabei
Trichomonas vaginalis
What are some common features of STIs?
Transmissible, manageable, often asymptomatic and avoidable
List the different types of sexual contact from highest risk of catching an STI to lowest risk
Fisting/traumatic sex Group sex Anal sex Vaginal sex Oral sex Touching someone's genitals with your own Mutual masturbation
What can be spread from genital contact only?
Pthirus pubis (public lice)
Scabies (sacroptes scabeii)
Warts (HPV 6 and 11)
HSV types 1 and 2
What tends to be spread through blood transmission/group sex?
Hep C
Why are STIs important?
They can kill, cause unpleasant symptoms, psychological distress and are costly and v. common
What are symptoms of STIs?
Ulceration (syphilis, herpes, chancroid)
Lumps (HPV 6 and 11)
Discharge (penis, rectum, vagina, eye)
Rashes (itchy/non-itchy, genital or trunk in HIV)
Systemic symptoms: fever, rash, lymphadenopathy, malaise, infertility, cervical cancer, adverse pregnancy outcomes
Why do diagnoses of STIs change over time?
- true change in no of cases (e.g. more condom use, more MSM, more sex and more partners, vaccination)
- change in no of diagnoses without change in no of cases (more awareness –> more tests –> more diagnoses) & better tests
Explain cores and assertive mixing
Some people have sex only with people similar to them
–> high prevalence in a certain group but limited spread
E.g. syphilis in those who exchange sex for drugs
Explain chains and random mixing
Some groups are v. large, e.g. heterosexual men and woman –> low prevalence but wider dissemination along chains
What is important to do in managing STIs?
Partner notification
Diagnosis and treatment
Health promotion
What are the two forms of partner notification?
Patient tells contact - client referral (preferred)
NHS tells contact - provider referral