Sexually transmitted infections 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
Difference between sub-clinical and clinical infection
sub-clinical has no symptoms but clinical does
Sexually transmissible microbe
A virus, bacteria or protozoan spread by sexual contact
Sexually transmitted infection
An infection by a pathogen which is sexually transmissible and unlikely to be transmitted by non-sexual means
Examples of STI
HPV type 6
Neisseria gonorrhoea
Sexually transmitted disease
a disorder of structure or function caused by a sexually transmitted pathogen
Examples of STD
Pelvic inflammatory disease
genital warts
Venereal diseases of 1916
syphilis
gonorrhoea
chancroid
Other STI’s in the UK - bacteria
bacterial - chlamydia trachomatis, klebsiella granulomatis, mycoplasma genitalium
organism in syphilis
treponema pallidum pallidum
organism in gonorrhoea
Neisseria gonorrhoea
Organism in chancroid
haemophilus ducreyi
STI viruses in UK
HSV, HIV, HPV, molluscum contagiosum
Parasite STI in UK
pthirus pubis
sarcoptes scabei
trichomonas vaginalis
Characteristics of STI
transmissible
asymptomatic?
manageable but not always curable eg HIV,HSV
avoidable
Implications of the characteristics of an STI
partner notification
hard to eradicate - prevention and education
treat and prevent complications
Type of sex from least to most chance of catching an infection
mutual masturbation genitals touching oral sex vaginal sex anal sex group sex
Genital contact only - transmission
pubic lice, scabies, warts and herpes
group sex - transmission
hep C
Systemic symptoms and complications of STI
fever, lymphadenopathy, rash, malaise
infertility, cervical cancer, adverse pregnancy outcomes in syphilis
3 reasons why STI’s are important
can cause morbidity and kill
drain on resources eg IVF, HIV meds, freezing warts
they are common
How many STI’s are acquired a day?
1M
How many people worldwide have genital herpes and HIV?
herpes - 500M
HIV - 37M
WHO STI 2016-2021 aim
zero new infections, STI related complications and deaths and zero discrimination
Changes in diagnoses of STI - 2 reasons why?
true change in number of cases
change in diagnoses `
Change in number of cases reasons
more sex, alcohol, beer goggles formula
Change in number of diagnoses reasons
greater awareness of STI’s - more testing
better tests - NAAT vs enzyme immunoassay
What is meant by a core?
people have sex with similar peope and high prevalence within a subpopulation eg syphilis and HCV
What is meant by a chain of mixing?
some cores are very big and random mixing leads to a low prevalence but wider dissemination along chains
Sexual history questions
last sexual encounter male or female? condoms? contraception type of sex casual vs regular nationality of contact
risk assessment for a man
sexual contact with a man IVDU? Sex with someone who is IVDU, outside UK medical procedures outwith UK sex industry
2 types of partner notification
patient tells - client referral
NHS tells - provider referral
Why offer further STI testing?
most STI’s are risk factors for HIV acquisition and transmission
if have 1 could have another
3 areas of health promotion
condoms (for chlamydia, HIV, gonorrhoea but not for HSV, warts)
oral sex carries risks (fellatio)
alcohol and drugs
How will eradication of STI’s come?
vaccines
