Viral gastroenteritis Flashcards
Name some viruses that replicate in the gut.
Poliovirus
Adenovirus (other than 40 and 41)
Hepatitis A
What are the 2 groups of viruses that are associated with gastroenteritis.
Norovirus and sapovirus
Rotavirus, adenovirus types 40 & 41 and astrovirus
Which group of people does the group of viruses containing rotavirus, adenovirus types 40 & 41 and astrovirus, predominantly effect?
Children under 2
Elderly
Immunocompromised
Describe norovirus (family, genetic material and subgroups).
From the Caliciviridae family
Non-enveloped, single stranded RNA
Six norovirus genogroups, three of which affect humans
- GI, GII, GIV
What is the most common cause of gastroenteritis outbreaks?
Norovirus
Give seven reasons norovirus the most common cause of gastroenteritis.
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
Where do norovirus outbreaks commonly occur?
Hospitals and residential facilities
What are the symptoms of a norovirus infection?
Vomiting Diarrhoea Nausea Abdominal cramps Headache, muscle aches Fever (minority of cases) Dehydration in the young and the elderly
In which population groups does norovirus become a more serious disease?
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
What is the treatment for a norovirus infection?
Symptomatic therapy
- IV/oral fluids
- antispasmodics
- analgesics
- antipyretics
What are the three mains ways that norovirus can spread?
Airborne
Faeco-oral
Food contamination
How can food become contaminated with norovirus?
Source - shellfish from contaminated water, contaminated water used for irrigation or human faeces used as fertiliser Processing Preparation Food handlers Customers Insects
How is norovirus diagnosed in a lab?
Faceal cultures
- tested by PCR
What is the best infection control for norovirus?
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
Whats the most common vector of spreading norovirus?
Contaminated hands = poor hand washing compliance
At what age is a rotavirus infection most common?
Under the age of two
- first infection after they have lost the protection of their mothers antibodies
Which group of patients have the more severe/persistent symptoms in a rotavirus infection?
The elderly and the immunocompromised
Describe a rotavirus (family, genetic material and infectious dose).
Part of the Reoviridae family
Double starnded RNA virsus
- 11 strands gives potential for antigenic variation
Low infectious dose (10-100 virus particles)
When are outbreaks of rotavirus most common?
The patients are most infectious when they have the diarrhoea and vomiting.
Outbreaks often occur in paediatric wards
What are the symptoms of a rotavirus infection?
Anorexia Low grade fever Watery, bloodless diarrhoea Vomiting Abdominal cramps
How is rotavirus treated?
There are no antivirals available so patients are kept well hydrated until the symptoms pass
Which rotavirus serotypes does the vaccine protect children against?
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
Adenovirus 40&41 and Astrovirus mainly act like rotavirus, but what is their differentiating factor?
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
How are rotavirus, astrovirus (with D&V) and adenoviruses 40&41 infections controlled?
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
