micro 5 Flashcards
what was the 8th leading cause of mortality in 2016?
diarrhoea
what is diarrhoea also known as?
gastroenteritis
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)
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)
what is the most common cause of travlers dihorrea?
e.coli (etec)
what is travelers diarrhea usually associated with?
- Traditionally associated with food borne diseases
* Classically water •More commonly poor sanitation/ hygiene practices
what is norovirus?
•Very infectious (<100 virus particles)
- can cayse diarohoeea
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
what season is norovirus most common around?
winter
what is noroviruses structure?
- Single stranded RNA virus
- Approx. 8Kb long
- Has 2 structural proteins;•VP1: The dominant protein
- VP2: Role not known
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
how many vp2’s are present in noroviruses?
1/2 copies
how many non-surgical protieins are present in norovirus?
6
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
how many rotavirus particles are neede to cause disease?
<100 virus particles may cause disease
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?
- E. coli attaches to the cell
- Heat stabile toxin secreted and interacts with guanylate cyclase-C receptor(GC-C)
- Increases cGMP
- Increases phosphorylation to CFTR
- Pumps Cl-out →contributes to osmotic diarrhoea
is there a vaccine available for enterotoxigenic e.coli?
no but there is some development on them
