Term
| A 4 month old infant presents to the pediatrician in February with watery diarrhea and vomiting of 24 hours duration. The child has not been able to keep down fluids for most of that time, and appears dehydrated. What is the most likely cause of this child's illness? |
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Definition
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Term
| Rotavirus: General Characteristics |
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Definition
- Reoviridae family
- dsRNA in 10-11 segments = allows for genetic rearrangment
- non-enveloped = stable in environment
- Group A commonly seen in humans
- most common manifestation is infantile gastroenteritis
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Term
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Definition
- infection more common in temperate climates in winter months
- most important cause of gastroenteritis in infants and young children
- ubiquitous, infects almost all children by 3 years of age
- infections begin around 6 months due to decline in maternal IgG
- able to remain for hrs to days on surfaces in environment
- can withstand pH (3-10)
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Term
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Definition
- enters body through ingestion
- viral capsid protein, vp4, binds to glycolipids on the membrane of villus epithelial cells in sm. intestine
- replicates in and lyses villus epithelial cells -> decrease level of disaccharidases -> diarrhea
- diarrhea also results from viral protein, NSP4, enterotoxin -> excess Cl- secretion
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Term
| Clinical Features of Rotavirus Infection |
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Definition
- Incubation period: 24 - 48 hrs
- Age: 4 months - 2 years, asymptomatic in adults
- Transmission: Fecal-oral, fomites
- signs: fever, nausea, diarrhea
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Term
| Signs and symptoms of Rotavirus Infection: |
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Definition
- high grade fever (>102 F) in 30% of individuals
- watery diarrhea without any leukocytes
- lasts 3-9 days, longer in malnourished and immune deficient
- mortality due to dehydration
- secondary malabsorption of fats and lactose
- chronic diarrhea
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Term
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Definition
- viral antigen VP6 in stool
- Grp A cultures in monkey kidney cells
- Nucleic acid detection (VP4 or VP7)
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Term
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Definition
dsDNA
non-enveloped = stable in environment
>47 serotypes are known
gastroenteritis associated with certain serotypes
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Term
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Definition
- 2nd most common viral cause of gastroenteritis
- transmission: droplets, fecal-oral
- most children infected by age 3
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Term
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Definition
- attacks mucoepithelial cells of the conjunctiva, respiratory tract, GI tract and GU tract
- destroy cells in villus -> decreease absorption of Na+ and water
- replicates in cytoplasm, DNA replication in nucleus
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Term
| Clinical Features of Adenovirus Infection |
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Definition
- Incubation period: 8 to 10 days
- transmission: Fecal-oral, fomit
- Signs: diarrhea for 5-12 days
- population: children, neonates
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Term
| Several people on an Alaskan cruise develop GI disease with abdominal cramps followed by vomiting as the predominant symptom; diarrhea, nausea, malaise and headache were present in about half the patients. Disease manifestations lasted 48 - 72 hours. What is the most likely pathogen? |
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Definition
| Calicivirus (Norwalk and Norwalk-like viruses) |
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Term
| Calicivirus: general characteristics |
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Definition
- small (+)ssRNA
- non-enveloped = stable in environment
- surface morphology consisting of cup-like hollows
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Term
| Characteristics of Calicivirus Infections |
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Definition
- often occur in outbreak fashion within confined populations (cruise ships, camps, institutions, etc.)
- more often affect adults and children over 4 yrs of age
- no fecal leukocytes
- no blood in stool
- Transmission: fecal-oral; shellfish, ingestion
- virus may remain viable after cooking contaminated food
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Term
| Norwalk Virus: Clinical Features |
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Definition
- incubation period: <24hrs
- transmission: fecal-oral, community outbreak
- signs: fever, nausea, diarrhea sometimes
- Duration: about 72hrs
- age: adults and children over 4
- most common in summer
- (Norovirus = similar winter vomiting disease)
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Term
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Definition
Norwalk-like virus
look like a star in electron microscope
diarrhea in kids <5yrs
most common in winter
difficult to diagnose |
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Term
| Common bacterial causes of enteric disease in immune suppressed: |
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Definition
- Shigella
- Salmonella
- Campylobacter
- Mycobacterium avium complex
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Term
| Common parasitic causes of enteric disease in immune suppressed: |
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Definition
- Cryptosporidia
- Microsporidia
- Isospora
- Giardia
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Term
| Common viral causes of enteric disease in immune suppressed: |
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Definition
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Term
| Which virus would be the prime suspect in an 8 month old with severe watery diarrhea progressing to dehydration? |
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Definition
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Term
| Which virus would be the probable cause of severe gastroenteritis symptoms in 50% of the guests who ate at a wedding banquet? |
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Definition
Caliciviruses: Norwalk or Norwalk-Like Viruses
common in outbreaks
incubation <24hrs
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Term
| Which viral agent would be suspected in an individual with diarrhea lasting over a week? |
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Definition
Adenovirus
diarrhea for 5 to 12 days! |
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Term
| Which virus would be significant as a cause of diarrhea in an immune compromised individual? |
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Definition
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Term
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Definition
Herpes virus family
dsDNA
enveloped
causes latent infection
immune compromised individuals |
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Term
| CMV in immune compromised |
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Definition
Enteritis: ulcers anywhere along GI tract
Retinitis
Pneumonia
CNS infection |
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Term
| Herpes Simplex Virus (HSV) in immune compromised |
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Definition
Symptoms: fever, nausea, emesis, diarrhea, ab pain, weight loss, esophagitis, colitis, proctitis
Untreated patients can develop tracheoesophageal fistuals, necrosis, stricture or hemorrhage
Biopsy: multinucleated giant cells, cytoplasmic inclusion bodies, ground glass appearance of nuclei |
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