Viral GI II Flashcards by tcarlso 3

What is the family of poliovirus? What is the genome type?

Picornavirus

+ssRNA

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Is polio stable at high or low pHs? What is the consequence of this?

Low, survives stomach

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What is the mode of transmission for polio?

Fecal-oral route

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What are the three serotypes for polio?

P1-3

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What is the incubation period for polio?

6 to 20 days

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What percent of polio are asymptomatic?

95%

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How is the polio virus shed?

In stool for weeks

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What three countries is polio still endemic to?

Afghanistan
Nigeria
Pakistan

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What are the clinical manifestations of “abortive” polio? Does this lead to paralysis?

Sore throat
Fever
GI symptoms

does not lead to paralysis

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What are the clinical manifestations of nonparalytic aseptic meningitis from polio? How long does it last?

Non-specific prodromal symptoms

Stiffness in back, neck or legs (usually unilateral)

Last 2-10 days

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What percent of polio cases result in flaccid paralysis?

<1%

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What percent of people infected with polio will have nonparalytic aseptic meningitis?

1-2%

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How do you diagnose polio?

Isolate from stool/CSF and sequence

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What was the first vaccine for polio?

Inactivated vaccine by Saulk

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What is the current polio vaccine?

Sabin, attenuated virus

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Does the vaccine strain in the Sabin vaccine replicate? How many strains does it provide protection?

Yes

Three strains

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What is VAPP? How often does it occur with the Sabin vaccine?

Vaccine-associated paralytic poliomyelitis

1 in every 2x10^6

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What is the standard polio vaccine today?

Inactivated vaccine

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How is the inactivated vaccine for polio made? Is there a risk for VAPP?

Grown in tissue cultures, and inactivated through formaldehyde

No risk for VAPP

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What are the symptoms of viral gastroenteritis?

N/v/d

Inflammation of the stomach and intestines

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What are the four virus families that cause viral gastroenteritis? Which ones are enveloped?

Rotavirus
Norovirus
Adenovirus
Astroviruses

None are enveloped

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What is the mode of transmission for viral gastroenteritis?

Fecal oral

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What is the incubation period for viral gastroenteritis vs bacterial? Why does the viral strain usually take longer to develop?

hour to 7 days for bacteria

1-3 days for virus (d/t need to replicated)

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Which cause of gastroenteritis causes vomiting more prominently, bacterial or viral?

Viral, usually

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What type of diarrhea do viral causes of gastroenteritis?

Watery--never bloody

How do you diagnose viral gastroenteritis?

One of exclusion--if stool culture is negative for bacterial causes

What is the major concern with viral gastroenteritis?

Dehydration

What is the treatment for dehydration caused by gastroenteritis?

IV or oral rehydration

What are the signs of severe dehydration?

``` Rapid pulse Tears absent Skin tenting Sunken eyes Lack of urination ```

What is skin tenting?

Pinching skin to see if dehydrated

What is the setting for viral vs bacterial gastroenteritis?

Bacterial = poor sanitation places Viral = similar in both developed and developing countries

What percent of children have had an infection with rotovirus by age 5?

95%

When is the most severe disease of rotavirus occur?

3-24 months of age

What percent of gastroenteritis is caused by rotavirus?

5-10%

What is the family of rotavirus? Genome?

Reovirus | dsRNA

What happens when the rotavirus enters a host cell?

Changes shape from sphere to star-like thingy with pores

What is the incubation period of rotavirus? How long do symptoms last?

1-3 days followed by 4-7 days of symptoms

Is fever seen with rotavirus infection?

Yes, 1/3 of pts have >102 F

Is rotavirus an opportunistic pathogen with HIV infections?

When is the rotavirus season?

Varies for different regions of the US, but spring time here

What is the most prevalent type of rotavirus?

What is the pathogenesis of rotavirus?

Infecting epithelial layer, and causing damage and malabsorption (vili blunting)

How many viral particles of rotavirus are needed for infection? How many are shed in the stool

10^9 release in stool

What is the toxin that rotavirus produces? What does it do?

NSP4, causes Ca release

What is viliblunting?

Destruction of microvili caused by rotavirus

How do you diagnose rotavirus?

EIA (enzyme immunoassay) from stool EM or RT-PCR iff needed

What is the treatment for viral gastroenteritis?

Rehydration

What is the prevention technique for rotavirus?

Handwashing/Sanitize fomites Vaccine

Which type of immunoglobin do babies receive from their mothers through breast milk that protects them from rotavirus?

IgA

What are the two vaccines against rotavirus? Which strains are these protective against? What type of vaccine is it?

Rotateq or rotarix G1-4, G9 Live attenuated human for rotratrix Reassortment from bovine for rotateq

When do children get vaccinated against rotavirus?

before 12 weeks of age

What is intussusception? Is there a concern for this with rotavirus?

a medical condition in which a part of the intestine invaginates (folds into) into another section of intestine. This is no longer a concern with current vaccines

How is the rotavirus vaccine administered?

Oral inhalation

Which population does norovirus usually infect?

All ages

What is the incubation period for norovirus?

24-48 hours

What are the symptoms of norovirus infection?

n/v/d Low grade fever

What is the pathology of norovirus?

Similar to rotavirus, micovilli blunting

What family does norovirus belong to? Genome type?

Caliciviridae family | +ssRNA

Who is particularly susceptible to norovirus infection [hint: not age or immune status]? Why is this the case?

Specific blood types more than other people May be d/t infecting immune cells

What is the mode of transmission for norovirus? Can it be spread from person-person?

Fecal oral route (vomit aerosolization, food handling) Can be transmitted from person-person

How does norovirus usually spread? Where does this usually occur?

Foodborne Long-term care facilities

What is the genome type of the adenovirus? Is there an envelope? Which serotypes cause GI disease?

dsDNA Naked capsid 40 and 41 serotypes

What is the incubation period for adenovirus? How long do symptoms last?

8-10 days 7-8 days of symptoms

What are the symptoms of infection with GI adenovirus?

n/v/ watery diarrhea

Is there seasonal variation of adenovirus?

nope

Which part of the population are usually infected with adenovirus?

Children

How do you diagnose adenovirus?

Antibody detection in stool sample

What is the family of the sapovirus?

Caliciviridae family

What is the genome type of astroviruses?

+ssRNA

How long does immunity last for norovirus?

Short

What are the usual places where the weakness caused by polio is observed? How long does it have to continue before it is deemed permanent?

Usually, unilateral lower limbs 12 months

How does polio cause paralysis?

Infection and replication within neurons