Lecture 15: STI's Flashcards
Incidence
First time infected/finite time
Prevalence
General level/time
Rate
Frequency (#of events/size of population) ex. attack rate
Do condoms work to eliminate HPV?
NO, just lower chances
Most common age for STI’s
15-24
3 factors determining rate of spread of STI’s
a) rate of exposure of susceptible ppl
b) efficiency of transmission per exposure
c) duration of infectivity of those infected
HPV
Major cause of human disease. Rate very high. Can cause cancer. Could get it, it lies dormant, and suddenly in your 40’s you have cervical cancer
STI transmission + acquiring
- Sex (vag/anal)
- Oral-gen
- I.V drugs (sharing needles)
- Congenital transmission (mom->baby)
- Women tend to be more bio prone to STI’s
Harm reduction strategies for preventing STI acquisition
- Abstinence (dumb)
- Practice safe sex
- Monogamous relationship (dumb)
- Reduce the # number of sexual partners
- Vaccination (HPV)
Bacteria STI’s
- Treponema pallidum
- Chlamydia trachomatis
- Neisseria gonorrhea
Viruses STI’s
- Human immunodeficiency virus
- Human Pappiloma Virus (HPV)
- Herpes Simplex Virus (HSV)
Parasites STI
Trichomonas vaginalis
Syphilis
- Caused by Treponema palladum
- Less common STI but on the rise
- Doesn’t produce painful sores
- Can be treated with penicillin
- Can be asymp
- Diagnoses: Treponemal Tests (IgG and IgM) as well as testing for non-syphilis specific proteins non-treponemal test
Stage 1 Syphilis
Shanker (non painful @ first sign of contact) -> then randomly dissolves
Stage 2 Syphilis
Develops a rash -> on palms and soles of feet
Rash is hard to see with freckles or dark skin then disappears
Stage 3 Syphilis
Can activate in brain, heart, etc causing severe complications
Can make you go mad
CNS involvement can lead to personality changes, emotional instability, memory impairment, etc
Chlamydia trachomatis
- Common, caused by intracellular bacteria called Chlamydia trachomatis
- Transmitted via sex (any kind), or from mom-baby
- Occurs worldwide
- Common in females vs males
- Incubation is 1-3 weeks
- Can ascend up gen tract leading to ectopic preg, and PID in women
Chlamydia trachomatis: 3 specific entities based on anatomical site
- Trachoma: ocular and leading cause of blindness
- Lymphogranuloma venereum: causes infection in rectal mucosa
- Genital infection: Inflammation of reproductive tract
Chlamydia trachomatis Types
- Trachoma: Ocular trachoma Serovar A, B, Ba, and C
- Lymphogranuloma venereum: Serovar L1, L2, and L3
- Genital Infection: D-K serotypes most commonly E, F, D
Chlamydia trachomatis diagnosis
Urine sample for both genders
40% of females who have Chlamydia trachomatis also have gonorrhea
Science of Chlamydia trachomatis (pathogenesis)
- Infects columnar epithelial cells, increases risk in adolescent females since these extend further into ectocervix in adolescents
- Epithelial cells as a result of infection recruit neutrophils to region which then lead to an inflammatory response
Chlamydia trachomatis symptoms MEN
- Itchiness
- Pain
- Discharge
- Swelling
1/2 will be asymp
Chlamydia trachomatis symptoms FEMALE
- Burning
- Vag discharge
- Bleeding
- Pain
- Lower back or ab pain
- Possible fevers and chills
- Itchiness
Lab detection of Chlamydia trachomatis
- Swabs are least traumatic method of collection for diagnosis
- Avoid cotton swabs
- Also test for gonorrhoea
- Cervical specimens can be collected
- Send the swabs for PCR for the detection of CT and NG
Neisseria gonorrhoea
- Always considered pathogenic and is not a notifiable disease
- Gram -‘ve cocci
- Humans are the only host for the pathogen
- 2nd most common bacterial STI
- Infects the mucous membrane in body including gen tract, rectum, pharynx, eyes
- Can lead to ectopic pregnancies
- Sex acquires or from mom to baby
- Rapidly developing multi-drug resistance
- 15-24 yr olds
- Incubation period of 2-8 days
How is Neisseria gonorrhoea diagnosed
With a swab as it needs to be cultured to determine how to treat it
Complications of Neisseria gonorrhoea
Potential systematic infections
- Arthritis
- endocarditis
-meningitis
Epidemiology and Transmission of Neisseria gonorrhoea
- Majority occur in 15-24 year olds
- Incubation period is 2-8 days
- 10% men and 50% women are minimally symptomatic or asymptomatic
- most cases will resolve in several weeks
- ALWAYS SEEK TREATMENT
Neisseria gonorrhoea and resistance
- Increasing resistance
- Associated with treatment failure “untreatable gonococcal infection”
- One of the WHO list priority organisms for emerging resistance over the next 10 yrs
Diagnosis of Neisseria gonorrhoeae
- Swab 2cm and rotate anterior portion of meal urethra
- Samples should be obtained after removal of mucous
- Dacron and Rayon swabs
- Send for PCR and Culture
STI Summary
- Highly prevalent especially in 15-24 year olds
- Significant proportion of individuals are asymptomatic
- ALWAYS seek medical treatment
- Emerging resistance is a problem with some such as (Neisseria gonorrhoeae) and not others (Treponema palladum)
