Enteric Viruses Flashcards
what are the 5 viral enteric pathogens?
rotavirus
norovirus
astrovirus
adenovirus
enterovirus
what are the 6 bacterial enteric pathogens?
salmonella spp.
shigella spp.
E. coli
campylobacter spp.
yersinia spp.
C. diff
what are the 3 parasite enteric pathogens?
entamoeba histolytica
giardia lamblia
cryptosporidium
what is viral gastroenteritis?
inflammation and irritation of stomach and small intestines
what are the symptoms of gastroenteritis?
acute nausea
vomiting
what is the onset of viral gastroenteritis?
1-3 days
when is viral gastroenteritis most common (season)?
winter
what replicates faster viruses or bacteria?
viruses
viral gastroenteritis is most common in what age group?
1-10 year olds
what are the 2 patterns of disease with gastroenteritis?
- mild afebrile illness + watery diarrhea
- severe febrile illness + watery diarrhea + vomiting + headache
what is the major problem associated with diarrhea?
dehydration
what are the 5 established pathogens for gastroenteritis?
- norovirus*
- rotavirus*
- astrovirus
- adenovirus
- calicivirus
is there a vaccine for norovirus?
no
what does rotavirus cause?
infantile gastroenteritis
astrovirus is especially common in the ____________ population
pediatric
what are the 2 likely and emerging pathogens?
1.coronaviruses
- enteroviruses
how do coronaviruses cause gastroenteritis?
same receptors in RT are also in GI
what types of enteroviruses cause gastroenteritis?
echoviruses
11
14
18
what is the incubation period for norovirus?
24-28 hours
what is the duration of illness for norovirus?
24-60 hours
quick onset and offset
what is the incubation period for rotavirus?
1-3 days
what is the duration of illness for rotavirus?
4-8 days
who is at risk for rotavirus?
< 2 years
norovirus is a member of the _______________ family
caliciviridae family
what kind of virus is norovirus?
non-enveloped
icosahedral
SS-positive sense RNA
describe the appearance of norovirus
scalloped border
cupcake indentations
how is norovirus transmitted?
fecal-oral
person-person
how many norovirus particles are needed for transmission?
~100
(very few)
when are you longer transmissible with norovirus?
once you are clinically well
what is the stability of norovirus?
non-enveloped, therefore highly stable
where is norovirus shed? when?
in stool
during first 24-48 hours of illness
how long can norovirus be detected in stool? how is it detected?
detected by PCR up to 3 weeks after illness
where are norovirus outbreaks most common?
closed settings
- hospitals
- nursing homes
- cruiseships
- university residences
when do most norovirus outbreaks end?
spontaneously after 1-2 weeks
How should surfaces contaminated with norovirus be cleaned?
high grade disinfectants
soap and water doesn’t work
what are the possible vehicles for norovirus?
any food, especially if contact with contaminated water
- shellfish
- ice
what are the signs and symptoms of norovirus?
abdominal cramps
nausea
vomiting
diarrhea
some have low-grade fever
how is norovirus treated?
no antibitics
treat symptoms
fluid replacement
electrolyte balance
what are the hospital control measures for norovirus?
contact precautions
hand washing
environmental cleaning
how long can norovirus survive on fomites?
21-28 days
rotavirus is part of the ____________ family
Reoviridae family
what kind of virus is rotavirus?
double stranded RNA
non-enveloped
what is the stability of rotavirus?
non-enveloped
highly stable
Rotavirus A
most clinically significant
causes gastroenteritis in KIDS
very high burden
what is the most clinically significant rotavirus serogroup?
A
Rotavirus B and C
causes gastroenteritis in all ages
Rotavirus D/E/F/G
non-human disease
Who is most likely to get rotavirus?
children < 3 years
what is the most common cause of severe gastroenteritis in children < 5 years?
rotavirus
when does the severity of rotavirus peak?
6 months - 2 years
almost all kids acquire the serum antibodies for rotavirus within __________________
first 2-3 years of life
where are rotavirus deaths most common?
Africa
India
how is rotavirus transmitted?
fecal-oral
rotavirus is NOT transmitted by ___________________ in Canada
contaminated food and water
how is rotavirus diagnosed?
detected in stool 4-10 days after symptom onset
up to 57 days by PCR
where are rotavirus outbreaks most common?
daycares
families
nursing homes
hospitals
explain the pathogenesis of rotavirus
malabsorption related mucosal damage and depression of disaccharides
blunted villi in duodenum
crypt hypertrophy and mononuclear infiltration
viral enterotoxin released into environment
activation of secretory reflexes in enteric nervous system causes fluid secretion
what are the symptoms of rotavirus?
vomiting and fever (2-3 days)
water diarrhea (4-5 days)
how does rotavirus cause death?
result of dehydration and electrolyte imbalance
leads to cardiac arrest
what are the extra intestinal manifestations of rotavirus?
respiratory infections
hepatic abscess
pancreatitis
myositis
meningoencephalitis
how is rotavirus treated?
rehydration
electrolyte balance
no antibiotics
how is rotavirus prevented?
hand hygiene
contact precautions
rotavirus vaccine
what is the dose regimen for rotavirus vaccine?
3 doses at 2, 4 and 6
how long does rotavirus survive on fomites at 85% humidity?
what about at 25-50% humidity?
up to 2 days
10 days
what are the 2 rotavirus vaccines?
- RotaTeq
- Rotarix.
what is the gold standard for detecting and diagnosing enteric viruses?
PCR
what are some other diagnostic methods for enteric viruses?
electron microscopy
antigen detection
