Viral gastroenteritis

Question 1

Name some viruses that replicate in the gut.

Answer 1

Poliovirus
Adenovirus (other than 40 and 41)
Hepatitis A

Question 2

What are the 2 groups of viruses that are associated with gastroenteritis.

Answer 2

Norovirus and sapovirus

Rotavirus, adenovirus types 40 & 41 and astrovirus

Question 3

Which group of people does the group of viruses containing rotavirus, adenovirus types 40 & 41 and astrovirus, predominantly effect?

Answer 3

Children under 2
Elderly
Immunocompromised

Question 4

Describe norovirus (family, genetic material and subgroups).

Answer 4

From the Caliciviridae family
Non-enveloped, single stranded RNA
Six norovirus genogroups, three of which affect humans
- GI, GII, GIV

Question 5

What is the most common cause of gastroenteritis outbreaks?

Answer 5

Norovirus

Question 6

Give seven reasons norovirus the most common cause of gastroenteritis.

Answer 6

Very low infectious dose (10-100 virions)
Tough - survives well in the environement.
Variety of transmission routes
- person-to-person (feacal-oral and aerosolised)
- foodborne
- water
Infectious period continues 48hours after symptoms stop
Immunity lasts less than a year
Continuing antigenic variation
All ages are at risk

Question 7

Where do norovirus outbreaks commonly occur?

Answer 7

Hospitals and residential facilities

Question 8

What are the symptoms of a norovirus infection?

Answer 8

Vomiting
Diarrhoea
Nausea
Abdominal cramps
Headache, muscle aches
Fever (minority of cases)
Dehydration in the young and the elderly

Question 9

In which population groups does norovirus become a more serious disease?

Answer 9

Childhood
Those that catch it from a hospital outbreak (lasts longer as well)
The elderly experience more post infection complications
Chronic diarrhoea and virus shedding in both solid organ transplants and bone marrow transplant patients

Question 10

What is the treatment for a norovirus infection?

Answer 10

Symptomatic therapy

• IV/oral fluids
• antispasmodics
• analgesics
• antipyretics

Question 11

What are the three mains ways that norovirus can spread?

Answer 11

Airborne
Faeco-oral
Food contamination

Question 12

How can food become contaminated with norovirus?

Answer 12

Source - shellfish from contaminated water, contaminated water used for irrigation or human faeces used as fertiliser 
Processing
Preparation 
Food handlers
Customers
Insects

Question 13

How is norovirus diagnosed in a lab?

Answer 13

Faceal cultures

- tested by PCR

Question 14

What is the best infection control for norovirus?

Answer 14

Isolation/cohorting
Make sure staff have been symptom free for 48hours
Don’t move patients or admit new patients
Thoroughly clean ward/hotel/bus/etc.
- dilute hypochlorite or hot soapy water
- 48 hours after last symptomatic case
Patient/visitor awareness

Question 15

Whats the most common vector of spreading norovirus?

Answer 15

Contaminated hands = poor hand washing compliance

Question 16

At what age is a rotavirus infection most common?

Answer 16

Under the age of two

- first infection after they have lost the protection of their mothers antibodies

Question 17

Which group of patients have the more severe/persistent symptoms in a rotavirus infection?

Answer 17

The elderly and the immunocompromised

Question 18

Describe a rotavirus (family, genetic material and infectious dose).

Answer 18

Part of the Reoviridae family
Double starnded RNA virsus
- 11 strands gives potential for antigenic variation
Low infectious dose (10-100 virus particles)

Question 19

When are outbreaks of rotavirus most common?

Answer 19

The patients are most infectious when they have the diarrhoea and vomiting.
Outbreaks often occur in paediatric wards

Question 20

What are the symptoms of a rotavirus infection?

Answer 20

Anorexia
Low grade fever
Watery, bloodless diarrhoea
Vomiting 
Abdominal cramps

Question 21

How is rotavirus treated?

Answer 21

There are no antivirals available so patients are kept well hydrated until the symptoms pass

Question 22

Which rotavirus serotypes does the vaccine protect children against?

Answer 22

G1P[8[
G2P[4]
G3P[8]
G4P[8]
G9P[8]
- Over 85% effective at protecting against severe rotavirus gastroenteritis in the first two years of life

Question 23

Adenovirus 40&41 and Astrovirus mainly act like rotavirus, but what is their differentiating factor?

Answer 23

Only the first infection is symptomatic (except in the elderly and immunocompromised)
Nearly everyone has been infected by the age of 5, and not all have symptomatic infections
Outbreaks are rare

Question 24

How are rotavirus, astrovirus (with D&V) and adenoviruses 40&41 infections controlled?

Answer 24

Isolation
Don’t move or admit new patients
Though cleaning of the ward 48 hours after last symptomatic case with a dilute hypochlorite solution
Patient/visitor awareness