2.12 Enteric Viruses

Question 1

What is the underlying pathology in inflammatory versus non-inflammatory gastroenteritis?

Answer 1

Inflammatory: Damage to intestinal mucosa from pathogen invasion or cytotoxins.

Non-inflammatory: Malabsorption or enterotoxin-mediated fluid secretion without significant mucosal damage

Question 2

What are the clinical signs of dehydration?

Answer 2

• Reduced urination or dark urine.
• Dry mouth and throat.
• Sunken eyes, absence of tears.
• Skin tenting.
• Rapid, weak pulse.
• Orthostatic hypotension
• Lethargy, irritability in children

Question 3

Why is identifying dehydration important in viral gastroenteritis?

Answer 3

major complication due to fluid loss from diarrhea and vomiting; timely rehydration prevents severe outcomes

Question 4

What are the main causative agents of viral gastroenteritis?

Answer 4

Rotavirus, norovirus, adenovirus (types 40, 41), and astrovirus

Question 5

Astrovirus modes of transmission and pathogenesis

Answer 5

Fecal-oral; damages intestinal epithelial cells

Question 6

Rotavirus modes of transmission and pathogenesis

Answer 6

Fecal-oral; infects small intestine, causing villi destruction and malabsorptive diarrhea

Question 7

Norovirus modes of transmission and pathogenesis

Answer 7

Fecal-oral, airborne droplets; binds histo-blood group antigens, disrupting intestinal cells

Question 8

Adenovirus modes of transmission and pathogenesis

Answer 8

Fecal-oral; replicates in gut, causing watery diarrhea.

Question 9

What is the peak age of incidence and seasonal variation for rotavirus?

Answer 9

Infants and young children; peaks in winter and spring (Dec–Jun)

Question 10

peak age of incidence and seasonal variation for norovirus?

Answer 10

All ages; outbreaks occur Nov–Apr

Question 11

What is the peak age of incidence and seasonal variation for adenovirus?

Answer 11

Primarily young children; no seasonal variation

Question 12

What are the route of administration, age recommendations, and production of the rotavirus vaccine?

Answer 12

Oral
RotaTeq (3 doses: 2, 4, 6 months), Rotarix (2 doses: 2, 4 months). Must start before 15 weeks of age.
Live attenuated, human and bovine strains

Question 13

common diagnostic methods for viral gastroenteritis?

Answer 13

Rotavirus: Enzyme immunoassay (EIA), RT-PCR.
Norovirus: Real-time qPCR, conventional RT-PCR outbreaks.
Adenovirus: PCR, EIA, antigen detection.
Astrovirus: EIA, immune electron microscopy

Question 14

Hepatitis type that is Fecal-oral; severe in pregnancy?

Answer 14

HEV

Question 15

What two kinds of hepatitis are blood borne with one with chronic infection risk and another with chronic liver damage?

Answer 15

HBV (infection)
HCV (liver damage)

Question 16

Which type of hepatitis is fecal oral and self limiting?

Answer 16

HAV

Question 17

Which kind of hepatitis requires co-infection with HBV?

Answer 17

HDV

Question 18

What are the hallmark symptoms of acute hepatitis?

Answer 18

Jaundice (skin/eye yellowing).
Dark urine, pale stools.
RUQ pain.
Fatigue, nausea, vomiting.
Fever during prodromal phase

Question 19

What are the key differences between HAV and HEV infections?

Answer 19

HAV: Common in developed and developing nations, resolves spontaneously, vaccine available.

HEV: Widespread in developing countries, severe in pregnancy, limited vaccine availability (China only) .

Question 20

How are HAV transmitted and prevented?

Answer 20

Fecal-oral. HAV via close contact
Prevent with Vaccination, hygiene.

Question 21

How are HEV transmitted and prevented?

Answer 21

Fecal-oral. via contaminated water/food.
Hygiene, avoid unsafe water/meat .

Question 22

significance of elevated bilirubin (>3mg/dL)?

Answer 22

Indicates jaundice; reflects impaired hepatic excretion

Question 23

significance of elevated liver enzymes (AST/ALT>1000U/L)?

Answer 23

Hepatocyte injury. ALT often higher in viral hepatitis

Question 24

What is a common characteristic of viruses that cause gastroenteritis?

Answer 24

Nonenveloped
They survive longer in the environment and as contagious fomites

Question 25

Who are most susceptible to viral gastroenteritis?

Answer 25

Infants and young children

Question 26

What is the most defining clinical feature of viral gastroenteritis?

Answer 26

Vomiting

Question 27

+ds RNA Virus and Segmented

Answer 27

Rotavirus

Question 28

What is notable about a segmented virus?

Answer 28

Can change their genotype easily

Question 29

+ss RNA ?

Answer 29

Norovirus, Astrovirus HAV and HEV

Question 30

DsDNA non enveloped?

Answer 30

Adenoviruses

Question 31

Most viruses that cause gastroenteritis have what transmission pattern?

Answer 31

Water borne and food borne

Question 32

Leading cause of severe diarrhea in children in developing world versus USA?

Answer 32

Rotavirus (develop) vs. Norovirus (USA)

Question 33

Key rotavirus structural proteins for vaccine development as neutralizing antibody targets?

Answer 33

VP4 (P pro) and VP7 (G pro)

Question 34

What contributed to rapid spread of rotavirus?

Answer 34

Very high infectivity (low infectious dose) and high number shed in stool

Question 35

What do rotaviruses target and how do they cause damage?

Answer 35

Villus epithelial cells with NSP4 enetrotoxin (& ca+ release)

Question 36

Most common test for rotavirus infection?

Answer 36

EIA stool sample

Question 37

What is unique about Noroviruses that allows them to survive in harsh environments?

Answer 37

Heat and acid stable

Question 38

What is essential for the norovirus to bind and infect?

Answer 38

ABH and Lewis blood group antigens (@saliva and mucosa)

Question 39

“Winter vomiting disease”?

Answer 39

Norovirus

Question 40

Common settings for norovirus outbreaks?

Answer 40

Long term care facilities, restaurants and catering… cruise ships 6%

Question 41

Preferred diagnostic test for norovirus?

Answer 41

Realtime qPCR Assay

Question 42

Adenovirus serotypes common in viral gastroenteroritis especially in young children?

Answer 42

40 and 41

Question 43

What is special about adenovirus attachment and toxicity?

Answer 43

Fiber proteins

Question 44

Best diagnostic test for adenovirus?

Answer 44

Stool but PCR done too

Question 45

What virus appears like a “star” under electron microscopy?

Answer 45

Astroviruses

Question 46

What virus looked like a “wheel” with electron microscopy?

Answer 46

Rotavirus

Question 47

What are key features of norovirus clinically?

Answer 47

Affects all ages and projectile vomiting

Question 48

What gastroenteritis viruses are year round?

Answer 48

Adenovirus, Astrovirus, and Sapovirus

Question 49

What is bilirubin normally conjugated to by hepatocytes in order to be excreted?

Answer 49

Glucuronic acid

Question 50

What is a sign of liver damage in if found in urinalysis ?

Answer 50

Unconjugated bilirubin

Question 51

What family does HAV belong to?

Answer 51

Picovirinidae

Question 52

Where does HAV replicate?

Answer 52

Hepatocytes and Kupffer cells

Question 53

What causes the liver damage in HAV?

Answer 53

Immune response (NK and CD8 T cells)

Question 54

How long are you protected for after recovering from HAV?

Answer 54

For life (Anti-HAV IgG antibodies)

Question 55

Is there a vaccine for HAV?

Answer 55

Yup, universal infant recommendation and high risk adults

Question 56

When does the HAV post exposure prophylaxis need to be administered?

Answer 56

Within 2 weeks

Question 57

What are the main HEV genotypes?

Answer 57

1&2 = human infection (develop) 3&4 = zoonotic (industrial)

Question 58

Most cases of HEV in the US are?

Answer 58

Travel related

Question 59

What are main clinal feature of HEV?

Answer 59

Jaundice and pruritus**

Question 60

What is the diagnostic tools for HAV and HEV?

Answer 60

HAV/HEV-IgM RT-PCR

Question 61

Unvaccinated child under <5 years with watery diarrhea and viral origin should hint at?

Answer 61

Rotavirus