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29 Cards in this Set
- Front
- Back
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Gastroenteritis
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Inflammation of the stomach and intestine
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Diarrhea
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Increase in number of stools w/decreased form
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Diarrhea
(pathology) |
(1) Electrolyte imbalance
(2) Osmotic factors (i.e. abnormal digestion, lactase insufficiency) (3) Disorders of gut motility |
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Viral Infections of the GI tract
(2 patterns of infection) |
Replication/disease in GI tract
Replication at GI but disease elsewhere |
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What GI viral infections result in disseminated disease?
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Enteroviruses and adenoviruses
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What is the most common cause of severe diarrhea worldwide?
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Rotavirus
Bacterial infections become more important in developing countries |
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Important GI-tract Viral Families
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"Cause poop to RACE through you"
Reoviridae Caliciviridae Astroviruses Enteric Adenoviruses |
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Reoviridae
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CROO
(coltivirus, orthoreovirus, orbivirus, rotavirus) Non-enveloped Double layer capsid Segmented dsRNA (enables reassortment) Name origin: Respiratory/Enteric Portals with no-associative symptoms ("Orphan") |
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Rotaviruses
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Genera of Reoviridae (non-enveloped, dsRNA, double-layer capsid)
Most common origin of viral gastroenteritis |
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Rotavirus
(classification) |
7 types based on VP6 (core) variation
A/B/C infect humans Serotypes determined by outer capsid proteins (VP4/7) |
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What antigen determines Rotavirus groups?
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VP6 (core) antigen
7 groups, A- G (but only A/B/C infect humans) |
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What antigen(s) determines Rotavirus serotype?
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VP4/7
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Group A Rotavirus
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Single most important agent of diarrhea in very young (>90% serotype (+) by 3!)
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Rotavirus
(pathogenesis) |
Fecal-oral route (via fomites)
Short incubation period (2 days) Virus shed in stool > week |
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Rotavirus
(clinical manifestation) |
Infants/children
Vomiting, diarrhea, abdominal cramping, fever, dehydration (may need to be rehospitalized for rehydration therapy) |
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Rotavirus
(diagnosis) |
Rapid Antigen Test
ELISA stool/rectal swap Detects VP6, group A variant |
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Rotavirus
(Management/Prevention) |
Rehydration
Vaccine? Earlier form pulled from market, new vaccine available for 6 - 32 week/old infants |
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Caliciviridae
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Of "RACE"
Causes gastroenteritis Importnant points: CANNOT CULTURE Non-enveloped (+) ssRNA Noro/Sapoviruses |
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Norovirus
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Of Caliciviridae ((+)ssRNA, non-enveloped and cannot culture)
LEADING CAUSE OF ACUTE GASTROENTERITIS IN OLDER CHILDREN/ADULTS |
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What is the leading cause of gastroenteritis in children? In adults?
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Children: rotavirus (of Reoviridae)
Adults: norovirus (of Caliciviridae) |
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Norovirus
(pathogenesis) |
Transmission via contaminated food/water or person-to-person spread (aerosolized vomitus!)
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Norovirus
(susceptibility to infection?) |
Strain-dependent binding to blood group antigens
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Norovirus
(Spectrum of symptoms) |
Inocculate patients w/same virus and get a broad spectrum of symptoms
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Astroviruses
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Cause Gastroenteritis
(cause poop to RACE through you) non-enveloped; ssRNA World-wide distribution (therefore, majority are sero (+) by 5) Generally affects infants/young children and problem w/institutional outbreaks |
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Enteric Adenoviruses
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Cause gastroenteritis (cause poop to RACE through you)
Non-enveloped, dsDNA (think, aDenoviruses) Serotypes 40/41 associated with diarrhea Longer incubation period (10 days) |
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What are the two leading causes of gastroenteritis in infants?
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Rotavirus (of Reoviridae family) and Enteric Adenoviruses
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Which Enteric Adenoviral Serotypes are associated with diarrhea?
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Serotypes 40 and 41
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ORT
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Oral Rehydration Therapy
(treating infants with serve dehydration). NOTE: the WHO makes distinct recommendations between world-wide vs. US ORT. Why? b/c the [salt] is TOO HIGH in the world solution |
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Q: Why is American ORT different from world-wide ORT?
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The world solution has too much salt
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