viral gastroenteritis Flashcards
viruses are..
obligate IC pathogens
viruses infect ??
thereby messing up ??
causing what type of diarrhea ??
enterocytes in the villi of the sm. intestine
disrupting both digestive and absorptive functions
osmotic diarrhea from inability to digest disaccharides
viruses transmitted via
fecal-oral route, but food and water can be major vehicles
virus clinical features
fever?
vomiting, diarrhea, abdominal pain
fever
some (norwalk, norovirus): ha and myalgias
virus dx
immunoassay or electron microscopy: RT-PCR (for Norovirus)
virus tx
supportive, fluid replacement (esp infants)
virus: vaccines?
for Rotavirus:
Tetravalent Rhesus Rotavirus-based Reassortant Live Oral Vaccine (RV-TV, Rotateq -Merck)
Wyeth’s vaccine no longer used: intussusception
virus prevention
soap and water > etOH hand san (Norovirus)
Rotavirus
dsRNA, segmented genome, serotypes (A* (US),B,C)
rotavirus vir. factor
enterotoxin NSP4: nonstruc. glycoprotein (diff. rec. w. age)
rotavirus immunogenic component of vaccine
G glycoprotein (G1-G4)-tetravalent also used to serotype virus
most common cause of sev. diarrhea in infants and young kiddos
rotavirus
(maj. cause infant mort., 3% hospitalizations
how is rotavirus spread?
can last for days-weeks where?
person-person -asymptomatic carriage is important on surfaces (changing diapers)
is rotavirus low or high dose organism?
LOW! mountain range–propagated
rotavirus presentation
how long?
dehydrating diarrhea, vomiting, fever, abd pain
5-7 days
(use BRAT diet)
norovirus
evolving?
ssRNA small, round, structured virus 7 genogroups (30 genotypes) new pandemic strain emerges every 2-4 yrs!
noroviruses recognize..
histo-blood group Ags in strain-sp. manner
ABO, Lewis and secretor families involved in norovirus binding
this gene ??? is determines susc. to norovirus infection
fucosyltransferase 2 (FUT2) gene
ppl with this trait ?? are resistant to norwalk virus
nonsecretors (20% Europeans)
norovirus shares characteristics with
norwalk virus
most common cause of infectious GE in all ages?
responsible for 50% of ??
80% of non-food-borne outbreaks occur where ???
norovirus also universal among children all food-borne GE outbreaks in US nursing homes, long-term care settings also hospitals
setting for 2/3 of norovirus FB outbreaks?
restaurants, then banquet and catering sites
1% non-food borne norovirus outbreaks attrib. to
cruise ships
norovirus: low or high dose?
spread how??
low (10 virions) spread aerosolized (vomit)
what virus resistant to chlorination and freezing and persists in the environment
norovirus
norovirus inf individuals are highly contagious for how long??
virus can be shed up to ?? post recovery
72 hrs post recovery (3 days)
2 wks
norovirus immunity last ??
2-3 yrs
norovirus onset?
12-48 hr incubation period (1/2 day to 2 days)
norovirus presents with ??
how long??
epidemic vomiting syndrome: acute vomiting*, diarrhea, *fever (low-grade), myalgia, ha
1-2 days
Kaplan’s criteria for dx viral GE outbreak
- mean/median illness duration of 12-60 hrs (0.5-2.5 days)
- mean/median incubation period of 24-48 hrs (1-2 days)
- > 50% ppl with vominting
- no bac agent previously found
norovirus dx
RT-PCR
Norwalk virus
ssRNA; 2 serotypes
norwalk virus causes what ??
in who??
but…
epidemics of vomiting and diarrhea
older children in adults
all ages are affected
norwalk virus occurs when??
associated with ??
summer
shellfish, other food, water is a common vehicle
Norwalk virus occurs in what groups?
community-wide outbreaks, families
nursing homes
norwalk virus presentation
duration?
acute vomiting, diarrhea, fever, myalgia and ha
1-2 days
enteric adenovirus
causes what in who ??
seasonality??
dsDNA
enteric diarrhea of infants and young children
no seasonality here
enteric adenovirus presentation
duration
prolonged diarrhea
5-12 days
vomiting and fever
