Dan - STIs Flashcards
R0 in regards to STIs
R0 (basic reproduction number) = B (transmission coefficient (efficiency)) * C (mean rate of partner change) * D (mean duration of infectiousness)
Define R0
Number of secondary cases caused by a single case of infection in a population that is totally susceptible with no interventions
Reducing transmission coefficient in STIs
eg Condoms
Reduce mean rate of partner change in STIS
(ie reducing R0 in STI spread)
Education
Reduce mean duration of infectiousness in STIs
Screening and early treatment
Asymptomatic screening
Syphilis vs HSV
Syphilis tends to be painless lesion
Treatment Chacroid
Ceftriaxone IM stat
Azithromycin PO stat
Cipro PO 3/7 or Eryhthromycin PO 7/7
Cannot use cipro if preg/breastfeeding
3 most important causes of genital ulcers
HSV - self limiting, vesicles
Syphilis - usually painless solitary
Chancroid - often painful +/- lymphadenopathy (less common since 1990)
What is syndromic management?
Use of treatment algorithms wi cure common causes of defined clinical syndromes
Advantages of syndromic management
Do not need specialist tests
Treat at first appt
Can potentially reduce mean rate of infectiousness
Quicker symptom relief
Cheap
Disadvantages of syndromic management
Risk of over treatment - drug resistance (using multiple drugs to cover multiple organisms)
Only symptomatic treated - women likely disproportionately disadvantaged
Issues with partner notification
Organism causing chancroid
Haemophilus ducreyi
Gram-negative coccobacilli bacteria
Cause of syphilis
Treponema pallidum
Stages of syphilis
Primary - local - chancre
Secondary - dissemnation, systemic illness
Latent period
Later/tertiary - skin/neuro/cardiac
Diagnosis Syphlis
Non treponemal test (RPR VDRL) - active disease/screening (False +ve SLE, Liver disease, HIV, leprosy)
Treponemal test - TPHRA/TPPA/FTA - exposure (positive for life)
Generally use combination of the two - RDT with both available
Name other spirochetes to syphilis
Borrelia - recurrentis. burgdorferi
Letospira
Yaws - treponema palladium petenue
Bejel T.P. endemic
Pinta - treponema carateum
Congenital syphilis
Poor prognosis neonates - 50% mortality
Range of disease
Chronic disease corresponds to tertiary syphilis in the adult
Syphilis screening in pregnancy
Gential Herpes
HSV - usually type 2
Incubation 2-7 days
Painful ulcers
Lifelong infection with recurrences
Neonatal herpes possible
PCR swab
Treat Acyclovir 5-10 days
Chancroid
Haemophilis duchy
Core groups - Africa/Asia/Central and S America
Incubation >10 days
Painful genital ulceration
Can get lymph avolvementL
Gram smear, culture
PCR
Azithro stat (generally penicillin/doxy resistant) resistance
Lympho Granuloma Venereum LGV
Clymadia trachomitis L1,2,3
Primary - painless genital ulcer
Secondary - lymphadenopathy, proctitis
Tertiary - chronic complications, lymphoedema
Culture
Serology
PCR
21/7 Doxy
Donovanosis
Klebsiella granulomatous
India PNG Carribean
Beefy red genital/anal ulcers usually painless
Lymphoedema, fibrosis, autoamputation of penis
Tissue smear Donovan bodies
Azithro or Doxy
Chlamydia Trachomatis
Intraceullar bacterium
Cervicitis and urethritis in females –> pelvic inflammation disease and infertility
Neonatal conjunctivitis/pneumonia in neonates
Urethritis in males
NAAT
Culture/serology
Doxy 7/7
Neisseria gonnohrea
Difficult to grow w gram negative diplococcus
urethritis males
Urethritis and cervicitis leading to PID/infertility in females
Microscopt
Culture
PCR
Ceftriaxone and azithro
Increasing ‘super gonorrhoea’
Neonatal conjunctivitis
Gonorrhoea
Chlamydiay
Eryhromycin or tetracycline ointmnet
Trichomonas Vaginalis
Commonest sexually transmitted pathogen
Asymptomatic
Thin green discharge
Microscopy - mobile protozoa
Culture
PCR
Antigen test
Metronidazole
Serotypes HPV
16 and 18 cervicogenic
6 and 11 most genital warts
Vacc now quadvalent boys and girls
