202/203: Reproductive Impact and Microbiology of STIs Flashcards
Which organisms are most commonly associated with urethritis in people with a vagina? (5)
- Chlamydia
- Gonorrhea
- HSV
- Trichomonas vaginalis
- Gardeneralla
Which pathogens can be transmitted to a neonate via breastmilk? (2)
HIV
HBV
Which of the following maternal and neonatal outcomes is NOT increased by maternal infection with clamydia?
- Ectopic pregnancy
- Spontaneous abortion
- Chronic pelvic pain
- Infertility
- Neonatal pneumonitis
b. Spontaneous abortion
All of the following may cause lesions on the genitalia except:
- HSV
- Treponema pallidum
- Haemophilus ducreyi
- Nesseria gonorrhoeae
- HPV
d. Nesseria gonorrhoeae
All others cause legions
Notably, treponema (syphilis) and HPV will be painless, HSV and ducreyi will be super painful
How does hormonal status affect chlamydia transmission?
Chlamydia target cells = endocervical cells
- Younger women tend to have more endocervical cells due to increased estrogen/progesterone
Name a parasite (1) and a bacteria (1) likely to cause vaginitis
Parasite: Trichomonas vaginalis
Bacteria: Gardenerella vaginella
What is the most important determinant in whether an HIV(+) mother will transmit HIV to the fetus?
How can risk of transmission be reduced?
Maternal viral load
HAART is highly effective in reducing transmission
C-section also plays a role, if mother has high viral load
Remember, HIV can be tranmitted transplacentlaly but also transvaginally during birth
Is chlamydia more likelty to be asymptomatic (and therefore undiagnosed) in men or women?
Women
Rank the following STIs in order from most to fewest new cases/year
- HPV (most)
- Chlamydia
- HIV
Why are women more susceptible to the acquisition of HIV than men through receptive vaginal/penile intercourse?
Women are exposed to more body fluids over a greater surface area for a long period of time
Young women are more likely to have a cervical ectropion -> target cells are more exposed to HIV
(Cervical ectropion = columnar cervical epithelium is present on the ectocervix)
Which STI is most strongly associated with cervical, vaginal, and vulvar cancer?
HPV
(High-risk = HPV-16, 18, 31, 33)
6 and 11 are low risk, cause genital warts
Which STI can be transmitted both transvaginally and transplacentally during gestation?
HIV
- Chlamydia, HSV, HBV are only transvaginal*
- Syphilis, Zika are only transplacental*
How is syphilis (treponema) diagnosed?
BOTH of the following tests:
- Non-trepomenal serologic assay (VRDL)
- Measures things associated with syphilis infection
- Sensitive, but not specific
- Treponemal serologic test (FTA-ABS)
- Detects treponema
- Specific
How has the strategy behind STI prevention efforts changed?
(Think “then vs. now”)
- Then: Aimed at reducing shared body fluids
- Abstinence
- Condom use
- Generally, relies on behavior change and not very successful
- Now: Goal is to reduce infectivity of infected individuals
- Test and treat
- PreP
- PeP
- Microbicides (ex: tenovofir gel)
- Circumcision (Fewer Langerhans cells on penis -> fewer target cells for HIV)
Which STI is most likley to present with swollen, painful joints and a sore throat?
Gonorrhea
(Especially if acquired through oral-genital contact)
What factors increase liklihood of HIV infection following an exposure? (3)
-
More virus particles introduced to the lumen
- Semen has the most HIV particles of any body fluid
-
More target cells (Langerhans cells = specific type of macrophage that have HIV coreceptor)
- There will be more of these cells if there is an existing STI
-
Disrupted epithelial surface
- Vaginal and anal epithelium are at baseline most susceptible to infection
- Progesterone and spermicide (nonoxyol-9) can increase breaks in mucosa
Perinatal infections that are transmitted transplacentally must cross which barrier to reach the fetus?
Must cross syncytiotrophoblasts
- STIs
- HIV
- Syphilis
- Zika
- Non-STIs
- HSV
- CMV
- Toxo
Which STIs can cause neonatal conjunctivis after perinatal transmission? (2)
- Chlamydia
- Delayed, milky discharge
- Gonorrhea
- Very soon after birth, thick/waxy discharge
Which STI can cause neonatal pneumonia and conjunctivitis?
Chlamydia
Gonorrhea can cause conjunctivitis but not pneumonia
What factors influence a person’s “rate of partner change” (3)
Context:
Rate of spread = efficiency of transmission * rate of partner change * duration of infectiousness
- Total number of partners
- Prevalence of infection in one’s social network
- Multiple concurrent partners (vs. one after the other)
Which cells are targeted by gonorrhoeae and chlamydia?
Columnar epithelial cells
- Reproductive tract
- Anal epithelium
What percentage of new STIs occur in young people?
50%
What sequelae can occur due to gonorrhea or clamydia infection in the female reproductive tract?
- Ascending infection -> Pelvic Inflammatory Disease
-
Results in tubal scarring
- -> Tuboovarian abscess -> sepsis -> death
- -> Ectopic pregnancy -> hemorrhage -> death
According to trend data, which demographic accounts for 75% of newly diagnosed primary and/or secondary syphilis cases?
Men who have sex with men (MSM)
Which STI can cause intrauterine growth restriction (IUGR) when passed transplacentally?
Syphilis
Which organisms are commonly associated with urethritis in people with a penis? (3)
- Chlamydia
- Gonorrhea
- HSV
All three of these are common in people with a vagina as well
Describe the process of HIV transmission
(Which cells are infected? How does it spread?)
- HIV targets mononuclear cells with the HIV coreceptor (CXCR4, CCR5)
- Macrophages, T cells
- More of these cells will be present if there is an existing infection or inflammation
- These cells are programmed to migrate to lymph nodes
- In the lymph nodes, virus is transmitted to other cells
Which non-STIs can cause intrauterine growth restriction (IUGR) when passed transplacentally?
Toxoplasmosis
Also: CMV, Rubella but Dr. Garcia said we only have to know toxoplasmosis
Perinatal infections that are transmitted transvaginally must cross which barrier to reach the fetus?
Chorioamnion
- STIs
- HIV
- Chlamydia
- HSV
- HBV
- Non-STIs
- Group B Strep
- Zika?
Why is somebody with an active gonorrhea infection more likely to acquire HIV?
Genital tract inflammation -> more inflammatory cells -> more target cells that HIV can infect
This is true for any inflammation from syphilis, bacterial vaginosis, chlamydia, gonorrhea
What is the equation for rate of spread of an STI?
Rate of spread = beta * c * d
- beta = efficiency of transmission
- c = rate of partner change
- d = duration of infectiousness
