Enteroviruses & Other Enteric Viruses Flashcards Preview

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Flashcards in Enteroviruses & Other Enteric Viruses Deck (20):
1

What are the major clinical symptoms associated with enteroviruses? (5)

depends on the target tissue-

 

Aseptic meningitis 

Pericarditis, myocarditis

Exanthems

Muscle weakness/paralysis

Conjuctivits 

2

How can you detect enterovirus infection?

 

What would a positive thorat swab suggest?

What would a positive fecal specimen suggest?

 

what is an exception to this?

Gather affected tissue/stool/body fluids, to perform a PCR (faster) or culture method (looking for CPE)

viremia is typically undetectable by the time symptoms appear 

 

What would a positive thorat swab suggest: infection within 2 days - 2 weeks 

What would a positive fecal specimen suggest: caution, infection could result in positive test up to 4 months

 

Except- hand, foot, mouth disease usually clinical diagnosis 

3

Major enteroviruses? 

Many (72 serotypes)

Cocksakie A and B,  echo and hepatitis A

4

What possible treatments are available? 

 

What is its limitations? 

 

What has been the tested effective dose? 

Pleconaril- blocks the production of infections progeny virus particles

 

Limitations against menigitis and myocarditis in children

Greater tna 90% of rhinovirus stereotypes inhibited at concentrates of 1mg per ml. 

 

MOA: binds to a hydrophobic pocket of the virion coat protein while virus particles are being assembled. Once pleconaril is bound and incorporated into the virion, the shape of the receptor binding canyon on the vision is altered, and the virion is unable to attach to the receptor and uncoat.

5

What are common sources of contamination of hep A?

What is the major route of transmission?

It is responsible for how many cases of hepatitis? 

shell fish, food handlers and day care centers

fecal-oral 

Responsible for 20-50% of hep cases

6

After how long will you start seeing signs of hep A infection?

 

What is the acute presentation of hep A? 

 

Labs?

incuabtion period lats 15-45 days

 

acute onset of fever, malaise, anorexia, h/a, n/v

clincially - jaudice, hepatospleno, dark urine

Usually self-limiting and non-fatal

 

ALT elevated for 5-10 days PRIOR to onset of jaundice and may remain elevated for 2-6 weeks

7

Diagnosis:

clinical presentation not reliable

acute infection - anti-HAV IgM detected in serum (after about 3.5 weeks of ingestion of virus)

HAV particles and/or HAV antigens detectable by immunoassay of the feces 

Detectable in liver biopsy and feces - 2-8 weeks 

In blood: 3-6 weeks 

8

Tx of HAV

 

Prophylaxis available? 

Who should receive it and when is it effective? 

usually self-liming and non-fatal

 

HAV vaccine

INACTIVATED/KILLED HAV 

 

adults - intramuscular injection followed by a 6-12 mo booster

Who should receive it? When is it effective? 

travelers to high/intermediate endemic of infection (africa, asia excluding japan, eastern europe, middle east, mexico, central and south a. parts of caribbean), 

children how live in high risk communities (mostly native rese=viors)

sexually active homosexual men 

others with high risk sexual behavior 

ppl with chronic liver disease (esp hep C infection )

ppl with occupational risk for infection 

Effective in preventing AND treating post-exposure

9

Viruses account for apron 75-80% of the cases of acute diarrheal disease. What are the most common viruses of diarrhea? (5)

Rotavirus, noroviruses/caliciviruses, astroviruses, adenoviruses, coronaviruses

10

How do you detect infection with Hepatitis A virus?

Difficult to grow - what is the best diagnostic test? visualization using electron microspco

what is its limitaiton? impractical and high cost

enzyme immunoassay available for rotavirus 

11

 rotavirus, huge impact on our population (over 3 million people are infected, mostly children <2), and economically. 

What months / where is it seen most often ??

nov-jan south west US? 

12

Pathogenesis of Rotavirus? Where does rotavirus infect? What is the pathogenic particle of rotavirus?

 

Symptoms? 

 

What is the new believed pathogenesis? what is the enterotoxin associated with its pathogenesis? 

transmits via human contact

SX: 

dehydration, diarrhea, vomiting, fever (= gastroenteritis??)

age-related; symptoms usually seen in children 6 mo to 2 y/o

 

Where does rotavirus infect? 

villus epithelium of the small  intestine 

Rotavirus encodes viral enterooxin NSP4 —> signal transduction pathway that leads to an increase in chloride intracellularly —> inc chloride secretion 

 

What are the properties of rotavirus enterotoxin NSP4? 

functions in viral morphogenesis, mobilizes calcium release from internal stores

13

How is rotavirus detected? 

 

Why is important to detect rotavirus and not just treat the symptoms? 

large # of viral particles excreted in the diarrhea; can be readily detected using EIA in a stool sample

 

high incidence of noscomal transmisison- children hospitalized with rotavirus infection should be isolated

14

is there immunity against rotaviruses?

 

Rotavirus vaccine?

is there immunity against rotaviruses? specific humor and secretory IgA antibodies are protective, probably inducing life-long immunity. 

 

Rotavirus vaccine? difficulties [rotavirus has 11 sements of DS-RNA, that can reassert during viral replication and packaging]..how does this happen? viruses with segmented RNA genomes can undergo reassortment 

RotaTeq (2006),

LIVE, attenuated virus, pentavalent including 5 serotypes

98% protection against severe diarrhea caused by rotavirus

—> induces a high level of protection against severe diarrhea illnesses caused by huma rotavirus

 

 

Risk? intussception - similar in vaccine and placebo patients

 When should it be give? 3 doses, spaced 2 months apart by mouth

first at 6-12 weeks of age, last at 32 weeks of age

 

RotaRix, human , LIVE attenuate vaccine based on predominant G1 genogroup of rotaviruses

15

Reassortment is important for:

1 generating vaccines for rotavirus, antigenic SHIFT (esp of influenza virus)

16

Q: what is the most common cause of non-bacterial, acute epidemic diarrhea?

 

What family are these viruses under? 

 

What are some features why they are one of the most common causes of diarrhea? 

 what is the most common cause of non-bacterial, acute epidemic diarrhea? 

Noroviruses 

 

What family are these viruses under? 

Calicivirus

Resistant to environmental pressures - drying, detergents, acids and temperatures

17

Where are noroviruses outbreaks typically taken place? 

 

How is it transmitted? 

 

What type of symptoms and when are they symptoms seen? 

Where are noroviruses outbreaks typically take place? 

college campuses and cruise ships 

 

How is it transmitted?

fecal-oral

 

What type of symptoms are and when are they seen?

rapid onset AND rapid resolution ~48 hours

many serotypes so multiple episodes possible 

18

What is the pathogenesis? 

 

How is it detected?

 

Is there current protection?

What is the pathogenesis?

compromise the function of the intestinal brush border, preventing proper absorption of water and nutrition 

Group 1 NoVs use human blood group antigens as their receptor on mucosal cells. 

Individuals that do not express FUT2 genee, are resistance to Group 1 novoviruses 

 

How is it detected? 

very acute nature of illness, so detection not usually done. 

film array RT- PCR assays can detect noroviruses in fecal samples

 

Is there any current protection? 

No, but the use of virus-like particles (VLPs) are being tested for possible vaccine. 

 

19

Major characteristics of the enterovirus group of viruses include all of the following EXCEPT:

A. Fecal-oral route of transmission.

B. Acid stable virion.

C. Proteolytic processing of the viral polyprotein to yield capsid and nonstructural

proteins. 

D. Primary viremia leading to spread of the virus to target tissues.

E. Majority of infections result in frank cases of disease. 

20

Reassortment occurs in which of these viruses:

 

A) Polioviruses and enteroviruses

B) Rotavirus and influenza virus

C) Yellow fever virus and Dengue virus

D) Ebola virus and Marburg virus

E) SARS coronavirus and MERS coronavirus

(b) - both ave segmented RNA genomes that can undergo ressortment if multiple viruses infer the same cells