sexual health Flashcards
(34 cards)
define commensal micro-organism
micro-organism derives food or other benefits from another organism without hurting or helping it
define pathogen
micro-organism that can cause disease
define 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
define sexually transmissible organism
a virus, bacteria, protozoan, insect or arthropod which can be spread by sexual contact
- can be commensal or pathogen
define sexually transmitted infection
infection by a pathogen which is sexually transmissible and which is unlikely to be transmitted by non-sexual means
- neisseria gonorrhoeae
- HPV type 6
define sexually transmitted disease
disorder of structure or function caused by a sexually transmitted pathogen
- pelvic inflammatory disease
- genital warts
give examples of venereal diseases and their causative agent.
- syphilis (Treponema pallidum pallidum)
- gonorrhoea (Neisseria gonorhoeae)
- chancroid (Haemophilus ducreyi)
give examples of other sexually transmitted organisms in the UK.
bacteria
- chlamydia trachomatis
- klebsiella granulomatis
- mycoplasma genitalium
viruses
- HSV
- HIV
- HPV
- molluscum contagiosum virus
parasites
- pthirus pubis
- sarcoptes scabei
- trichomonas vaginalis
give examples of sexual contact
- group sex
- anal sex
- vaginal sex
- oral sex
- touching someone else’s genitals with yours
- mutual masturbation
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 symptoms can STIs present with?
- ulceration
- lumps
- genital discharge
- non genital discharge
- rashes
- systemic symptoms: fever, rash, lymphadenopathy, malaise, infertility
What are the possible complications of STIs?
- infertility (chlamydia)
- cancer
- adverse pregnancy outcomes
why do diagnoses of STIs change over time
a difference in the number of cases
- transmissibility
- rate of acquiring new partners
change in the number of diagnoses but no change in cases
- greater awareness of STI = more testing
- better tests
- more clinicians considering STIs
how can we tell if there is change in the number of cases of STIs?
Ro = bcd
Ro (reproductive number) = average number of infections produced
b = likelihood of transmission per encounter
c = rate of acquiring new partners
d = duration of infectivity
Ro = bcd
Ro >1 then epidemic is sustained
Ro <1 then epidemic reduced
what testing methods are used?
- nucleic acid amplification testing
- enzyme immunoassays for chlamydia
modelling and mapping the spread of STIs
cores and assortative mixing
- some people have sex with people like them = high prevalence within a subpopulation
chains and random mixing
- random mixing = lower prevalence but wider dissemination along ‘chains’
what are the principles of management for someone presenting with symptoms suggestive of STI?
good history
partner notification: client referral, provider referral
HIV testing
health promotion: condoms, vaccination, hazardous drug use
genital symptoms
- lumps and swellings
- discharge from an orifice
- pain
- rashes
- cuts, sores, ulcers
- itching
- change in appearance
cause of genital symptoms
- STD
- microbial problem
- non-microbial problem
what microbial conditions of the genitals are not regarded as STDs?
- vulvovaginal candidosis
- bacterial vaginosis
- balanoposthitis – anaerobic/candidal
- tinea cruris
- erythrasma
- infected sebaceous glands
- impetigo
- cellulitis
vulvovaginal candidosis
- 90% Candida albicans (can be C. glabrata et al)
- usually acquired from bowel
- asymptomatic, if symptomatic: thrush, itch, discharge
- risk factors: diabetes, oral steroids, immune suppression, pregnancy, reproductive age group
- diagnosis: gram stained preparation, culture
- treatment: antifungal azoles (clotrimazole, fluconazole)
