Rotavirus is a dsRNA viruses Genome is only 18555 nucleotides in total Most common cause of diarrhoeal disease in infants and young children

micro 5 Flashcards by Niamh Walsh

what was the 8th leading cause of mortality in 2016?

diarrhoea

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what is diarrhoea also known as?

gastroenteritis

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what is gastroenteritis?

Inflammation of the GI tract (particularly the stomach and small intestine
Other things can inflame the GI tract but we are talking about microorganisms here)

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what is travlers diahorrea?

Inflammation of the GI tract (particularly the stomach and small intestine
Other things can inflame the GI tract but we are talking about microorganisms here)

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what is the most common cause of travlers dihorrea?

e.coli (etec)

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what is travelers diarrhea usually associated with?

Traditionally associated with food borne diseases

* Classically water •More commonly poor sanitation/ hygiene practices

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what is norovirus?

•Very infectious (<100 virus particles)

- can cayse diarohoeea

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how many subgroupes and genotypes does the norovirus have?

At least 6 different genogroups(I to VI) and >40 genotypes

* GII causes the most human infections

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what season is norovirus most common around?

winter

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what is noroviruses structure?

Single stranded RNA virus
Approx. 8Kb long
Has 2 structural proteins;•VP1: The dominant protein
VP2: Role not known

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what is VP1 subdivided into?

180 copies form a t=3 icosahedral viron (explanation here)
Made up of 2 domains;•P (protruding) domain•P1 binds P2 and S domains •P2 involved in antigenicity and cell attachment•S (shell) domain highly conserved

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how many vp2’s are present in noroviruses?

1/2 copies

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how many non-surgical protieins are present in norovirus?

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what is rotavirus?

Rotavirus is a dsRNA viruses
Genome is only 18555 nucleotides in total
Most common cause of diarrhoeal disease in infants and young children

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how many rotavirus particles are neede to cause disease?

<100 virus particles may cause disease

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how many species are there of rotavirus?

8 species of rotavirus

* Classified A-H •Humans primarily infected by A-C•A causes >90% of infections in humans

how can you further clasify rotavirus group a ?

based on serotype of 2 viral surface proteins
•G protein
•P protein

how is rotavirus usually transmitted?

Transmission mainly via faecal-oral route

* Improved sanitation/hygiene practices do not decrease prevalence

when is the virus contageous?

•Virus may start shedding before symptom onset and continue to be shed after symptoms have been resolved

what is the rota virus’ structure?

6 structural and 6 non-structural proteins

what are the 6 structural proteins in the rota virus? and what do they do?

VP1: RNA polymerase
VP2: Inner core layer binds RNA genome
VP3: Capping enzyme (guanylyl transferase; protects viral mRNA from nucleases)
VP4: Surface spike. Involved in binding to target. Determines P-type.•Determines how virulent the virus is
VP6: Major capsid protein. Used to lab identify rotavirus A.
VP7: Glycoprotein, makes up outer surface of the virus. Used to determine G-type

what are the two main non- structural proteins in the rotavirus and what do they do?

NSP1: Interferon antagonist

* NSP4: Viral enterotoxin (induces diarrhoea)•Secreted form causes ↑Ca2+ in host cells

how do you treat the rota and the nora virus?

No specific treatments available for Rotavirus and Norovirus infections
Focus on management of symptoms
Particularly dehydration due to fluid los

when are antivirals used for treatment?

•Antivirals are not used for Rotavirus and Norovirus treatment

which virus is there a vaccine available for?

Vaccine available for Rotavirus but not Norovirus

how is the rota virus made up?

the vaccine varries depending on where you are

what does the rota virus vaccine protect againts?

•Children in UK vaccinated against type A rotavirus•8 weeks and 12 weeks

what kind of vaccine is the rota virus?

* Rotarixis a live attenuated vaccine * Produced by growing on verocells * Based on the RIX4414 strain * Each dose contains ≥106CCID50

what is eschericha coli?

•E.coli is a very large and diverse group of bacteria

where is E.coli usually found?

* Commonly found in human gut/warm blooded mammals | * Facultativelyanaerobic•Can adapt to different ecological niches

how can strains subdivided?

* O antigen: Part of the LPS * K antigen: Capsule * H antigen: Flagellin

what are the two main types of e.coli that are studied well?

Enterotoxigenic | Shiga toxin producing

what is enterotoxinigenec e.coli most assoicated with?

most common cause of travelers diahorrea

what are the important virulence factors associated with enterotexigenic e.coli?

•Toxins (plasmid or transposon);•Heat-stable toxin (ST)•Heat-labile toxin (LT) * Surface structures * Colonization factors * Plasmid mediated fimbrialor surface antigens

what is the diorrheal process of how enterotexigeneic e.coli toxins work?

1. E. coli attaches to the cell 2. Heat stabile toxin secreted and interacts with guanylate cyclase-C receptor(GC-C) 3. Increases cGMP 4. Increases phosphorylation to CFTR 5. Pumps Cl-out →contributes to osmotic diarrhoea

is there a vaccine available for enterotoxigenic e.coli?

no but there is some development on them