Infection

Question 1

What is gastroenteritis?

Answer 1

Diarrhoea +/- vomiting due to enteric infection with viruses, bacteria or parasites.

Question 2

What are the two most common causes of gastroenteritis?

Answer 2

1. Viral - norovirus

2. Bacterial - campylobacter

Question 3

What are the two common viral causes of gastroenteritis and what is the format of their genetic material?

Answer 3

1. Norovirus - ssRNA

2. Rotavirus - dsRNA

Question 4

What is the difference between incubation period and length of illness for norovirus and rotavirus causing gastroenteritis?

Answer 4

1. Norovirus - 12-48h after exposure lasting 24-72h

2. Rotavirus - 48h after exposure, lasting 3-8d

Question 5

What are the eight most common bacterial causes of gastroenteritis and what type of bacteria are they?

Answer 5

1. Salmonella: gram -ve anaerobe
2. Campylobacter: gram -ve rod
3. E. coli: gram -ve anaerobe
4. Shigella: gram -ve anaerobe
5. Clostridium perfringens: gram +ve anaerobe
6. Clostridium difficile
7. Listeria
8. Bacillus cereus

Question 6

What bacterial causes of gastroenteritis also cause bloody diarrhoea?

Answer 6

1. Campylobacter
2. E. coli (if Shiga-toxin producing)
3. Shigella

Question 7

Which parasites cause gastroenteritis?

Answer 7

1. Giardia

2. Cryptosporidium

Question 8

What is the most common cause of traveller’s diarrhoea?

Answer 8

Enterotoxigenic E. coli

Question 9

What is the treatment for traveller’s diarrhoea?

Answer 9

1. Oral rehydration - Dioralyte

2. Antimotility agents - loperamide (avoid in bloody diarrhoea)

Question 10

What is the most likely cause of persistent diarrhoea (>14 days/dysentery)?

Answer 10

Giardia