5.2 Gastrointestinal viruses Flashcards
What are the general features of viruses that cause acute gastroenteritis?
Small but very tough - non enveloped, resistant to drying and hard to disinfect
Rapid disease course - incubation down to 24 hours and symptoms from 24 hours to 7 days
Spectacular replication - low minimal infectious dose and massive yield
What kinds of viruses are rota, noro and adenovirus?
rotavirus: double stranded RNA virus
Norovirus: single stranded RNA virus
Adenovirus: DNA virus
How many types of rotavirus are there and which causes infantile diarrhoea?
Seven (A-G) with A being the major cause of infantile diarrhoea
What is the typical course of rotavirus?
3 days of vomiting that starts first and 5 days of diarrhoea that overlaps
What are the pathological changes in rotavirus?
Direct viral damage to enterocytes at the tips of the vili and shortening of the vili, malabsorption and secretion
What virus protein is thought to play a role in rotavirus and how?
NSP4
mess with IC Ca
Direct impact on tight junctions
interacts with the CNS
What is the transmission of rotavirus?
Fecal-oral, environmental contamination
What is the rotavirus structure?
genome in 11 segments with VP4 and VP7 encoding the major surface proteins G and P giving rise to the serotypes
What are the most common serotypes of rotavirus?
G1-4 and now G9
What are the vaccinations for rotavirus?
Live attenuated vaccine
Rotarix: single genotype
Rotateq: collection covering G1-4 and P1
How can you minimise the risk from rotavirus immunisation?
Stick to schedule, don’t vaccinate risk groups (immunocomprimised or ill), vigilance, advise parents of side effects
What is the structure of norovirus?
Capsid composed of one major and one minor protein with the major capsid protein (VP1) forming virus like particles
What is the genome of norovirus?
single stranded RNA with 3 open reading frames
What is the role of the open reading frame 1 (ORF1)?
polyprotein that encodes the proteinase to cleave this into active units
What is the replication strategy for norovirus?
‘hit and run’ massive replication before the innate immunity kicks in
