Enteroviruses & Other Enteric Viruses Flashcards
What are the major clinical symptoms associated with enteroviruses? (5)
depends on the target tissue-
Aseptic meningitis
Pericarditis, myocarditis
Exanthems
Muscle weakness/paralysis
Conjuctivits
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
Major enteroviruses?
Many (72 serotypes)
Cocksakie A and B, echo and hepatitis A
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.
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
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
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
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
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
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
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?
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
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
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
Reassortment is important for:
1 generating vaccines for rotavirus, antigenic SHIFT (esp of influenza virus)
