B5.007 Acute Infection Diarrhea: Viral and Protozoal Causes

Question 1

clinically significant diarrhea

Answer 1

> 3 episodes within 24 hrs

Question 2

toxigenic diarrhea characteristics

Answer 2

incubation- <6 h
symptom duration- 24 h
vomiting- +++
fever- - 
leukocytes- -
RBCs- -

Question 3

viral diarrhea characteristics

Answer 3

incubation- 1-2 days
symptom duration- 1-4 days
vomiting- ++
fever- +/-
leukocytes- -
RBCs- -

Question 4

bacterial diarrhea characteristics

Answer 4

incubation- 1-2 days
symptom duration- 5-7 days
vomiting- -
fever- +/-
leukocytes- +/-
RBCs- +/-

Question 5

protozoal diarrhea characteristics

Answer 5

incubation- days/weeks
symptom duration- weeks-months
vomiting- -
fever- - 
leukocytes- - (except Eh)
RBCs- - (except Eh)

Question 6

when do you test diarrhea?

Answer 6

hospitalized > 3 days
severe symptoms or high risk
> 7 days duration

Question 7

enveloped virus

Answer 7

picks up host membrane (lipid bilayer when budding)

not environmentally hardy (sensitive to heat, disinfectants, alcohol)

Question 8

nonenveloped virus

Answer 8

exit cell by lysis or vacuole (exocytosis)
protein coat
environmentally hardy
most transmitted fecal oral

Question 9

norovirus pathogenesis

Answer 9

infects cell in small intestine
broadening and blunting of villi
transient malabsorption of sugars and fats
decreased activity of brush border enzymes

Question 10

host factors affecting norovirus pathogenesis

Answer 10

NoV receptor
ABO blood type- O > A > B = AB
secretor status- expression of FUT2 allele on histo blood group antigens also expressed on mucosal epithelial cells

Question 11

advantages of syndromic based testing for diarrhea

Answer 11

single orderable test
increased detection for difficult to culture/ detect organisms
rapid turn around 1-2 h

Question 12

limitations of syndromic based testing for diarrhea

Answer 12

too much info
limited epidemiological and treatment info
susceptibility testing requires additional time/culture
costly