Infectious disease 3

Question 1

Chikungunya virus initially replicated where?

Answer 1

Fibroblast of dermis then disseminates

Question 2

Zika virus most infectious when?

Answer 2

first 30 days from symptoms

Question 3

Congenital Zika syndrome features?

Answer 3

Microcephaly + Thin cerebral cortices
Macular scarring
Contractures + hypotonia

Question 4

Dengue virus if infected - immunity last for how long?

Answer 4

2 years

Question 5

Dengue in tropical areas vs cooler areas?

Answer 5

Aegpyti in tropical

Albopictus in cooler climate

Question 6

How Dengue hemorrhagic shock and fever occurs?

Answer 6

Viral protein NS1 - disrupt endothelial glycocalyx so more vascular permeability

Question 7

When to do NS1 antigen to detect dengue?

Answer 7

< day 4

day 5 = dengue serology

Question 8

Platelet transfusion in dengue?

Answer 8

No role - cause more harm - increase length of hospitalization and recovery of platelet counts

Question 9

When to give Dengvaxia vaccine?

Answer 9

Past hx of dengue infection if not - in naive patient - more severe dengue infection and higher rate of hospitalisation

Question 10

How does dengue virus gain entry?

Answer 10

Fc receptor of target cells - macrophage

Question 11

Chronic carrier of thyphoid - tx?

Answer 11

Ciprofloxacin for 4 weeks

Question 12

MDR thyphoid definition?

Answer 12

Resistance to first 3 line abx drugs

• Chlorampenicol
• Ampicillin
• Cotriomaxole

Question 13

XDR thyphoid definition?

Answer 13

Resistance to at least 5 abx

Question 14

Thyphoid from india or SEA - treatment?

Answer 14

Ceftriaxone or Azithromycin

Question 15

Thyphoid from pakistan - treatment?

Answer 15

Carbapenem - bcoz resistant to ceftriaxone

Question 16

Thick screening in Malaria purpose?

Thin screening in malaria purpose?

Answer 16

Thick - screening

Thin - species identification and quantification

Question 17

Why artesunate cause hemolytic anemia?

Answer 17

Produces ROS that kills parasite but in the process cause hemolysis

Question 18

When use Tefanoquine?

Answer 18

P. vivax/ovale but G6PD assay must be > 70%

Question 19

Commonest malaria species ?

Answer 19

P. Falciparum

Question 20

Why glandular fever - sero-conversion period in HIV?

Answer 20

CD8 kills infected CD4 cells

Question 21

What is associated with slower progression to AIDS?

Answer 21

HLAB57

Question 22

Why overtime immune system can’t beat HIV virus?

Answer 22

HIV mutant clones bind poorly to MHC I thus CD8 can’t regconise it

Question 23

Bnabs - broadly neutralizing antibodies not effective in HIV?

Answer 23

Bnabs targets glycoprotein 41/ 120 on virus

virus learns to evade by 20 weeks

Question 24

Why TAF (tenofovir) better than TDF (tenofovir)?

Answer 24

TDF rapidly absorbed in gut and excreted by kidney - so need higher dose but then causes renal toxicity

Question 25

Nevirapine causes what side effect?

Answer 25

Fatal hepatitis

Question 26

PREP : High risk factors for Transgender and MSM?

Answer 26

Last 3 months - Condomless anal intercourse - partner HIV +ve - Methamphetamine use - Rectal chlamydia/gonorrhea/syphilis

Question 27

PREP regimen and test?

Answer 27

``` Tenofovir/Emtricitabine Test UEC+ ACR - every 3 months Syphilis/HIV serology - every 3 months Hep C every 12 months ```

Question 28

PoEP : Non-occupational exposure = Known HIV Lowest risk activity for contracting HIV Highest risk activity for contracting HIV -When to give PoEP and not to give PoEP?

Answer 28

- Receptive/insertive oral intercourse - lowest - RAI - receptive anal intercourse - highest - KNOWN HIV :unknown/detectable viral load or not on treatment = oral intercourse - no need give PoEP - KNOWN HIV : viral load NOT DETECTABLE - no need give PoEP - Everything else give PoEP ( 3 drugs)

Question 29

PoEP : non-occupational exposure = Dunno if got HIV lowest risk activity for contracting HIV? highest risk activity for contracting HIV? -When to give PoEP?

Answer 29

- Needlestick injury/Receptive or oral insertive oral intercourse/ mucous membrane contact but no skin breakage = lowest - NO NEED PoEP - RAI + ejaculation - everything give PoEP ( 2 drugs) except mentioned above

Question 30

PoEP : occupational exposure = HIV source | when to give PoEP?

Answer 30

Give in all scenarios Viral load KNOWN to be undetectable : 2 drugs Unknown/high viral load/not on treatment : 3 drugs

Question 31

What is PoEP regimen?

Answer 31

start within 72 hours from exposure and therapy for 1 month 2 drugs : 2 NRTI - tenofovir + emtricitabine/Lamivudine 3 drugs : 2 NRTI + 1 INSTI drug