Lecture 12: STIs

Question 1

STIs require ____ contact for transmission and ____ ____ to allow for occasional opportunities for transmission. They may remain as ____ infections or may ____. They can be an important cause of ____ disease

Answer 1

intimate, persistent infection, local, disseminate, neonatal

Question 2

Bacterial STI

Answer 2

chlamydia, gonorrhoea, syphilis

Question 3

Viral STI

Answer 3

HPV, herpes, HIV

Question 4

Fungal STI

Answer 4

candidiasis

Question 5

Protozoal STI

Answer 5

trichomoniasis

Question 6

more than ____ STIs are aquired every day worldwide. Each year there is an estimated ____ million new infections with ____ of ____ curable STIs: chlamydia, gonorrhoea, syphilis and trichnomiasis. More than ____ million 15-49 year old estimated to have genital infectin with HSV

Answer 6

one million, 376, one of four, 500

Question 7

What are some common symptoms of STIs

Answer 7

1. Urethritis - can be purulent
2. Cervicitis - can be purulent
3. Epididymitis - chronic pain, infertility, hypogonadism, defective hormone production

Question 8

What are some complications of untreated symptoms?

Answer 8

PID - uterus, fallopian tubes, ovaries
can lead to ectopic pregancy, infertility and chronic pelvic pain

Question 9

Chlamydia is caused by the bacterium ____ ____. ____ serovars are classified by prominent outer membrane protein ____

Answer 9

Chlamydia thrachomatis, a-k, OmpA (virulence factor)

Question 10

What is the function of serovars in chlamydia?

Answer 10

A-C infect conjunctival epithelial cells - blindness.
D-K infect genital tract epithelial cells - pelvic inflammatory disease, ectopic pregnancy, and sterility
L1-L3 infect epithelial cells and macrophages, causing an invasive infection.

Question 11

Lymphgranuloma venereum (LGV) can infect ____ and spreads through ____. it is predominantely found in ____. It causes ____ in the groin and ____ which is inflammation of the colon and rectum

Answer 11

macrophages, lymph nodes, men who have sex with men, buboes, proctocolitis

Question 12

gential serovars transmission

Answer 12

transmitted vaginally, orally and anally
can be passed to baby during childbirth
> 70% women asymptomatic
~ 25% men asymptomatic
can be cured with AB

Question 13

if genital serovars are left untreated they can lead to ____ , which manifests as ____ ____ and ____ .

Answer 13

PID, chronic pelvic pain, ectopic pregnancy, infertility

Question 14

genital serovars can lead to ____ ____ and ____ in babies born vaginally to infected women. In untreated men can lead to pain, swelling and inflammation of the ____ and ____ , ____ , ____ and ____

Answer 14

Neonatal, conjunctivitis, pneumonia, epididymis, testes, urethritis, reactive arthritis, infertility

Question 15

how many people are infected with Chlamydia in nz per year? how is this data acquired

Answer 15

28,000, voluntary provision of data
(almost double rates of UK and Australia)

Question 16

incidence of chlamydia is highest in which demographic?

Answer 16

20-24 y/olds

Question 17

how is chlamydia diagnosed?

Answer 17

culture from swab or urine
PCR amplification of DNA
Antigen detection by microscopy or ELISA

Question 18

____ and ____ are not effective in treating chlamydia. A single dose of ____ is currently the recommended first line treatment and is effective in 94% of patients but is less effective in treating ____ chlamydia. BPAC recommend ____, 100 mg twice a day for seven days

Answer 18

penicillin, cephalosporins, azithromycin, rectal, doxycyline

Question 19

What is the EB in chlamydia infection?

Answer 19

elementary body - metabolically inactive but highly infectious

Question 20

What is RB in chlamydia infection?

Answer 20

Reticulate body - metabolically active and replicative form

Question 21

Explain the pathogenesis of chlamydia

Answer 21

1. EB enters cell, transforms IB and then RB
2. RB begins to divide within inclusion memrbane, T3SS needles penetrate IM to secrete effectors
3. RBs begin to differentiate back into EBs
4. Infectious EB escape by cell lysis or extrusion to initiate new infection

Question 22

Gonorrhoea is caused by bacterium ____ ____ and ____ most prevalent bacterial STI

Answer 22

Neisseria gonorrhoeae, second

Question 23

gonorrhoea is transmitted during ____ sex. Female to male = ____% / episode, male to female = ____ % /episode. Can be passed to baby during childbirth.

Answer 23

vaginal, oral, anal, 20%, 50%

Question 24

Gonorrhoea symptoms and what happens if left untreated?

Answer 24

• pain and inflammation/buring during urination
• systemic dissemination

Question 25

Gonorrhoea became a notifiable disease under the health act in 2017. ____/100000 population.

Answer 25

75

Question 26

Incidence of gonorrhoea is higher in?

Answer 26

males than females
(98 vs 66 cases per 100,000)

Question 27

What age demographic is most affected by gonorrhoea

Answer 27

20-24 y olds

Question 28

Treatment for gonorrhoea

Answer 28

penicillin initially effective (MIC <0.01mg/L) - now accumulation of mutations in porins, aquisition of gene for new transpeptidase. MIC now 1 mg/L. Then plasmid with gene for beta-lactamase - MIC now > 64 ml/L

so now intramuscular ciprofloxacin treatment with oral azithromycin (attacks chlamydia too)

Question 29

Syphilis caused by ____ ____

Answer 29

treponema pallidum

Question 30

In syphilis the infection is ____ with a visible ____. a painless ulcer that heals spontaneously

Answer 30

local, chancre

Question 31

if syphilis is left untreated, it leads to secodary disease in ____ weeks resulting in ____ ____ which is a widespread rash

Answer 31

2-8 weeks
bacteriaemic dissemination

Question 32

Symptoms of syphilis include

Answer 32

rash, fever, malaise, aseptic meningitis, hepatitis

Question 33

If syphilis is left untreated it can lead to teritaty disease years later and manifests as ___ ___ _ . inflammation of blood vessles affecting the brain and artery

Answer 33

small vessel vasculits

Question 34

In pregnant women, untreated syphilis leads to ____ or ____ in half of pregnancies.

Answer 34

miscarriage, still birth

Question 35

What is the treatment for syphilis?

Answer 35

penicillin - no resistance