Flashcards in viral gastroenteritis Deck (38):
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
vomiting, diarrhea, abdominal pain
some (norwalk, norovirus): ha and myalgias
immunoassay or electron microscopy: RT-PCR (for Norovirus)
supportive, fluid replacement (esp infants)
Tetravalent Rhesus Rotavirus-based Reassortant Live Oral Vaccine (RV-TV, Rotateq -Merck)
Wyeth's vaccine no longer used: intussusception
soap and water > etOH hand san (Norovirus)
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
(maj. cause infant mort., 3% hospitalizations
how is rotavirus spread?
can last for days-weeks where?
-asymptomatic carriage is important
on surfaces (changing diapers)
is rotavirus low or high dose organism?
LOW! mountain range--propagated
dehydrating diarrhea, vomiting, *fever*, abd pain
(use BRAT diet)
ssRNA small, round, structured virus
7 genogroups (30 genotypes)
new pandemic strain emerges every 2-4 yrs!
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
most common cause of infectious GE in all ages?
responsible for 50% of ??
80% of non-food-borne outbreaks occur where ???
also universal among children
all food-borne GE outbreaks in US
nursing homes, long-term care settings
setting for 2/3 of norovirus FB outbreaks?
restaurants, then banquet and catering sites
1% non-food borne norovirus outbreaks attrib. to
norovirus: low or high dose?
low (10 virions)
spread aerosolized (vomit)
what virus resistant to chlorination and freezing and persists in the environment
norovirus inf individuals are highly contagious for how long??
virus can be shed up to ?? post recovery
72 hrs post recovery (3 days)
norovirus immunity last ??
12-48 hr incubation period (1/2 day to 2 days)
norovirus presents with ??
epidemic vomiting syndrome: acute vomiting*, diarrhea, *fever (low-grade), myalgia, ha
Kaplan's criteria for dx viral GE outbreak
1. mean/median illness duration of 12-60 hrs (0.5-2.5 days)
2. mean/median incubation period of 24-48 hrs (1-2 days)
3. >50% ppl with vominting
4. no bac agent previously found
ssRNA; 2 serotypes
norwalk virus causes what ??
epidemics of vomiting and diarrhea
older children in adults
all ages are affected
norwalk virus occurs when??
associated with ??
shellfish, other food, water is a common vehicle
Norwalk virus occurs in what groups?
community-wide outbreaks, families
norwalk virus presentation
acute vomiting, diarrhea, *fever*, *myalgia and ha*
causes what in who ??
enteric diarrhea of infants and young children
no seasonality here