Viruses Of The Gastointestinal Tract Flashcards
What are symptoms of acute viral gastroenteritis?
Diarrhoea
Vomiting
Abdominal discomfort
Fever
Rotavirus, norovirus, enteric adenovirus, astrovirus, calcivirus
What is epidemic gastroenteritis caused by?
Norovirus
What is sporadic gastroenteritis in very young people caused by?
Rotavirus
What is sporadic acute gastroenteritis caused by?
Calicivirus
Rotavirus
Astrovirus
Adenovirus
What is the difference in immunity for norovirus?
Immunity is shortlived and occurrence is outbreak, so can kee getting the same strain
How do people transmit GI viruses?
Can be transferred to food via ill worker or ingested orally by new host from food or water which contains virus
What are the biggest cause of norovirus?
Shellfish
What is rotavirus morphology?
A genus within the family reoviridae, resembles a wheel hence rota
Non enveloped
What is the rota virus genome?
dsRNA segmented
Structural viral proteins
Outer capsids
Core proteins
Non structural proteins
What is rotavirus classification?
Group A - significant diarrhoea illness in the young, more important , vaccines are made to sterotypes within this group
Group B - annual epidemics in adults especially in china
Group C - sporadic child cases, also in outbreaks
Group D, E and F - in animals, thus far
What are the four most common strains of rotavirus?
P8G1, P8G3, P8G4, P4G2
How are strains named of rotavirus
VP4 antigen: P (protease-cleaved protein)
Serotype; 8 human viruses
Therefore p8G1
What is pathogenesis of rotavirus?
Infect upper two third of duodenal epithelial cell
Infectious particles are released to intestinal lumen and undergo further replication in distal areas
What happens to microvilli in rotavirus?
End up with problems with microvilli becoming shortened , they can’t absorb nutrients like normal
What happens to epithelia in rotavirus?
Increased paracellular permeability by weakening tight junctions between cells
What is diagnosis and treatment for rotavirus?
Antigen enzyme immunoassay (EIA) of stool specimens
RT-PCR
Non-specific treatment: oral rehydration therapy to prevent dehydration
Intravenous fluid is required in several infant cases
Immunisation by vaccines
What is the rotashield vaccine?
Three viruses contain 10 genes from simian strain RRV and gene segment 9 (vp7) from human strains G1, G2, or G4
The fourth virus is simian strain RRV (whose vp7 is similar to human G3)
What was the risk of rotashield?
Intussusception, this is inversion of the intestines with one another , was taken off the market despite it being a good vaccine
What is rotarix?
Derived from one strain - P8G1
Relies on cross reactivity - not so effective on P4G2 strains
What is rotateq?
Derived from bovine-human recombinant by reassormtnet
Grows less well int he human gut requires multiple doses
But has P8 G1-G4
What is hyperemesis hiemis?
Winter vomiting disease
