Viral Gastroenteritis Flashcards
(21 cards)
Define viral gastroenteritis
Inflammation of the stomach and intestines caused by viruses and characterised by diarrhoea and vomiting
Who is at higher risk of viral gastroenteritis?
- children under 5
- old age (esp if living in a nursing home)
- immunocompromised
List the viruses that cause gastroenteritis
- norovirus and sapovirus (calciviridae)
- rotavirus
- adenovirus 40 and 41
- astrovirus
What individuals are affected by norovirus/sapovirus?
- all ages + healthy individuals
- young + elderly can have serious infection
What individuals are affected by rotavirus/adenovirus/astrovirus
Mainly:
- children under 2
- elderly
- immunocompromised
(Because immunity is built up over time in immunocompetent + adults)
Describe the structure of norovirus
- calciviridae family
- non-enveloped, single stranded RNA virus
- 3 (of 10) genogroups affect humans = GI, GII, GIV
- GII-4 most common
Describe the features of transmission of norovirus
- person-person (faecal-oral, aerosolised)
- food-borne
- water
- infectious dose very small
- stable + can remain viable for long time in environment
- 24-48 hrs incubation
- can shed for up to 3 weeks after infection
Describe the clinical features of norovirus
- asymptomatic but most have symptoms
- vomiting
- non-bloody diarrhoea
- nausea
- abdominal cramps
- headaches, muscle aches
- low-grade fever
- dehydration in young and elderly
(Usually lasts 12-60 hours)
Describe the complications of norovirus
- childhood hospitalisation
- illness in hospital outbreaks last longer + have increased risk of mortality
- (because patients are usually more frail and have an underlying illness)
- chronic diarrhoea + virus shedding (up to 2 years) in organ transplant patients + bone marrow patients
List the possible treatments for norovirus
Symptomatic therapy:
- oral and/or IV fluids
- antispasmodics
- analgesics
- antipyretics
Describe the immunity period associated with norovirus infection
- 6-14 weeks
- a vaccine has not been able to be created due to issues with culturing and limited understanding of immunity
How can norovirus infection be kept under control in the hospital setting
- isolation/cohorting
- exclude symptomatic staff until symptom free for 48 hours
- do not move or admit new patients (until last case asymptomatic for 48 hrs)
- thorough cleaning with dilute hypochlorite/hot soapy water
- patient/visitor awareness
Describe the structural features of rotavirus
- reoviridae family
- double stranded, non-enveloped RNA virus
- 5 predominant strains G1-4, G9
- virus contains 11 strands of RNA so has the potential for antigenic variation (replicative changes)
- stable in environment and fairly resistant to hand washing
Describe the transmission of rotavirus
- low infectious dose
- person-person (faecal-oral, fomites)
- food + water spread possible
- viral shedding up to 10 days after in stool (can be longer in immunocompromised)
Describe the clinical features of rotavirus
- incubation period 1-3 days
- manifestation depends on if 1st infection or reinfection (1st more severe)
- watery diarrhoea, abdominal pain, vomiting, loss of electrolytes (dehydration)
- symptoms can last 3-7 days
List the possible complications of rotavirus
- severe chronic diarrhoea
- dehydration
- electrolyte imbalance (due to fluid loss)
- metabolic acidosis
- immunodeficient children can have more severe or persistent disease
Describe how immunity is generated in rotavirus
- antibodies against VP7, VP4 and secretory IgA (viral proteins)
- 1st infection does not lead to permanent immunity
- each subsequent infection leads to further reductions in severity
Rotavirus vaccine
- derived from a virus which was isolated and attenuated by serial cell culture passage (to not cause illness but induce immunity)
- part of childhood immunisation schedule
Describe the features of adenovirus
- adenoviridae family
- double stranded DNA virus
- > 50 serotypes that cause disease (40 and 41 cause gastroenteritis)
- symptoms: fever + watery diarrhoea
- supportive treatment
Describe features of astrovirus
- astroviridae family
- single stranded, non-enveloped RNA virus
- causes less severe gastroenteritis
- usually causes sporadic cases (outbreaks usually in young children)
Describe the process of diagnosing viral gastroenteritis
PCR which detects the DNA/RNA in a vomit or stool sample
