Infectious diarrhea

Question 1

What agent is the leading cause of prolonged infectious diarrhea, dehydration from diarrhea, hospitalization diarrhea, and death from diarrhea?

Is there a vaccine for this agent?

Answer 1

Rotavirus.

There is a live attenuated oral vaccine. Yes, there is a vaccine. Cases in the US are almost 0, but the efficacy in developing countries is not so goo.

Question 2

Rotavirus is a disease mostly of (children or adults)? What is the mode of transmission? What is the duration of illness?

Answer 2

Children under 5

Fecal-oral route

5-8 days duration.

Question 3

This virus affects family and community epidemics in the winter, and typically affects all age ranges. What is the transmission? What is the duration of illness?

Answer 3

Norovirus

Fecal-oral epidemics.

1-2 day duration.

Question 4

If a child gets sick and the family doesn’t, that is more likely to be (norovirus or rotavirus)?

If the whole family gets sick?

Answer 4

Child–> rotavirus

Family–> norovirus.

Question 5

What is a classic presentation of Giardia?

Answer 5

Patient presents with diarrhea, fatigue, borborygmy, malodorous stool (steatorrhea), cramps and flatulence.

Question 6

Name the non-inflammatory diarrheas touched on in class.

Answer 6

Rotavirus
Norovirus
Giardia
Cholera
ETEC

Question 7

Name the agents producing inflammatory diarrhea.

Answer 7

C. jejuni
Salmonella sp.
Shigella sp.
EHEC
E. histolytica

Question 8

Would you see fecal leukocytes in a non-inflammatory diarrhea?

Answer 8

No. Antibiotics will not be effective.

Fecal leukocytes are seen in the inflammatory diarrheal diseases, so abx are more likely to be effective.

Question 9

What is hemorrhagic colitis?

Answer 9

Stool with gross blood.

Question 10

Is there a benefit of treating susceptible E coli 0157:H7 with antibiotics?

Answer 10

No. First of all, you lyse the orgamisms releasing a wave of toxins. You also may ramp up toxin production, or throw off the microbiome in favor of the infecting organism.

Question 11

Verotoxin Shiga-like toxin (SLT-I/II)
Binds especially to human renal endothelial cells
Inhibits protein synthesis

What bug is associated with this toxin?

Answer 11

E. coli 0157.H7

Question 12

What are the symptoms of C. difficile overgrowth?

Answer 12

Symptoms may be mild diarrhea, watery or bloody, or may have fever, leukocytosis with severe colitis

Question 13

C. diff is a _____ (gram, morphology)?

Answer 13

Gram positive rod.

Question 14

What is a major risk of C. diff?

Answer 14

Death from diarrhea.

BUt recurrence is a big problem. Hence the fecal transplany to avoid abx use.

Question 15

College student goes to Mexico for the summer, develops acute, non inflammatory diarrhea (watery, no blood, no fever).

Answer 15

ETEC

Question 16

Ceviche in peru, acute abd pain, profuce 20x/day watery diarrhea. No fever, no blood. Several others ill. What could it be?

Answer 16

Could be noro.

Could be V. cholerae

Question 17

Trekker in Nepal develops gas, bloating, diarrhea, does not respond to quinolones. Loses 10 lbs.

Answer 17

Giardia lamblia

Doesn’t cause pathology…just lots of diarrhea.

Question 18

What is visible on histologic exam of the small bowel of a cholera patient?

Answer 18

No bleeding, ulceration, villous blunting, etc.

No overt pathology. Purely a physiological mechanism.

Question 19

The toxin of this bacterium is very similar to V. cholerae, but not as severe. cAMP mediated, 2 part toxin, etc.

Answer 19

ETEC (Enterotoxigenic E. coli)

Question 20

What is the second leading cause of death worldwide due to infectious causes?

Answer 20

1) pneumonia

2) Diarrhea. (tied with HIV)