Exam 4 - STDs

Question 1

What three pathogens can cause sexually transmitted infections? What are the 8 most common pathogens that fall in these categories? Are they curable?

Answer 1

bacterial: syphilis, gonorrhea, and chlamydia
- curable

parasitic: trichomoniasis
- curable

viral: hepatitis B, herpes simplex virus, HIV, and human papillomavirus
- incurable

Question 2

What is the difference between a sexually transmitted infection and disease?

Answer 2

• most diseases begin with infections (but not all)
• infections may progress into diseases
• infection occurs when sexually transmitted pathogens first enter the body and begin multiplying (can be asymptomatic)
• disease occurs when the pathogen officially disrupts the body’s normal functions and processes

Question 3

How can STIs be transmitted?

Answer 3

predominantly by sexual contact, but some also through non-sexual means such as via blood or blood-products (HIV, Zika, Ebola)

many STIs can also be transmitted from mother to child during pregnancy and childbirth (syphilis, hep B, HIV, chlamydia, gonorrhea, herpes, and HPV)

Question 4

Why are untreated STIs and STDs a major health concern?

Answer 4

mother to child transmission can cause stillbirth, neonatal death, low birth weight, prematurity, sepsis, pneumonia, neonatal conjunctivitis, and congenital deformities
In 2016, 1 million pregnanct women had untreated syphilis, resulting in 350,000 adverse birth outcomes including 200,000 stillbirths or neonatal deaths

otherwise…
increase risk of another STI (having an STI increase risk of HIV)
cancer and death (HPV infection causing cervical cancer)
infertility (pelvic inflammatory disease, etc.)

Question 5

What is the difference between incidence and prevalence?

Answer 5

prevalence: number of infections (new or existing) in a given time

incidence: estimated number of new cases (diagnosed or undiagnosed)

prevalence is greater than incidence when an STD can be treated but not cured

Question 6

What are the symptoms of syphilis?

Answer 6

both men and women experience 4 stages

Primary: 3 weeks after infection, one or more chancre appear at original site of infection on mouth, sex organs, or anus; highly contagious
Secondary: Rash covers entire body, may be accompanied by flu-like symptoms; highly contagious
Latent: No symptoms, although lesions may appear on internal organs and tissues; not contagious
Tertiary: Heart disease, nerve damage, tissue death (necrosis), or mental defect

Question 7

What are the symptoms of chlamydia?

Answer 7

women:
May be asymptomatic in 65% of women
Unusual vaginal discharge
Burning while urinating
Lower abdominal pain
Bleeding between periods
Low fever

men:
May be asymptomatic in
25% of men
Discharge from penis
Burning while urinating
Pain and swelling of testicles

Question 8

Which age groups, sexes, and races are most affected by STDs?

Answer 8

Age group 20-24 have highest numbers of chlamydia and syphilis

More women diagnosed with chlamydia
More men diagnosed with syphilis

Black/AA men and women have highest rates of chlamydia
Black/AA, AI/AN men have highest rates of syphilis but AI/AN women have highest rates of syphilis

Question 9

What body fluids and tissues can be used to diagnose STIs?

Answer 9

blood, urine, oral swab, and vaginal swabs can be used

Question 10

What is tested to diagnose chlamydia and syphilis?

Answer 10

chlamydia: swab and urine test, preferred is nucleic acid amplification test (NAAT) that detects genetic material of Chlamydia trachomatis

syphilis: blood test, detects antibodies produced in response to Treponema pallidum infection

Question 11

Which STDs are nationally reportable and why is that data collected?

Answer 11

Chancroid, Chlamydia, Gonorrhea, Hepatitis B, HIV, Syphilis

permits identification of disease trends, tracking of outbreaks, and contact tracing

Question 12

What are treatment options for bacterial, parasitic, and viral STDs?

Answer 12

Antibiotics
– Three bacterial STIs (chlamydia, gonorrhoea and syphilis) and one parasitic STI (trichomoniasis) are generally curable with single-dose regimens of antibiotics

Anti-virals
– For herpes and HIV, the most effective medications
available are antivirals that can modulate the course of the disease, though they cannot cure the disease
– For hepatitis B, antiviral medications can help to fight the virus and slow damage to the liver

Question 13

What are the 6 methods to prevent STIs?

Answer 13

sexual education
abstinence
decrease risky behaviors (alcohol, drugs, multiple sexual partners)
condoms (for intercourse related transmission)
vaccines (HPV, Hep B)
male circumcision (reduces heterosexually acquired HIV by approx. 60%)

Question 14

Describe the anatomy of the penis. Which structures are made of which type of epithelium?

Answer 14

Foreskin is a continuation of the skin of the shaft of the penis that covers the glans and the urethral meatus. The frenulum is a thin band that connects the foreskin tot he ventral aspect of the glans.

Inner lining of foreskin, frenulum, and urethral
meatus are mucosal epithelium, which is thin, moist and susceptible to abrasion.
Glans and shaft are covered with keratinized
epithelium, which provides protection against
friction, microbial invasion and desiccation.

Question 15

What penile structures are altered during circumcision?

Answer 15

foreskin is removed

Question 16

How can HIV be transmitted?

How can circumcision decrease risk of HIV based on the penile anatomy?

Answer 16

1. Mucosal epithelium of inner foreskin has a high concentration of Langerhan’s cells, CD4+ helper lymphocytes, macrophages and dendritic cells (targets for HIV infection). When foreskin is pulled back during intercourse, that surface is exposed to vaginal secretions. Glans is keratinized and distal urethra has less Langerhan’s cells, so they are less susceptible.
2. Highly vascularized frenulum is susceptible to
   micro-abrasion trauma during intercourse.
3. Ulcerating lesions associated with other STDs
4. Foreskin sac may serve as a reservoir for HIV containing secretions resulting in prolonged contact time after exposure to secretions

Question 17

Why might circumcision not decrease the risk of HIV for men in the US?

Answer 17

In the US, most HIV transmission occurs among men having sex with men (MSW). Only 15% of men with HIV acquire it through male-female sex. Rectal mucosal secretions have a higher concentration of HIV than vaginal or cervical secretions, so the viral excess outweighs the positive effect of being circumcised.