Cholera. Differential diagnosis of enteritis. Flashcards
what is the PATHOGEN ?
vibrio cholera
what are the CHARACTERISTICS OF VIBRIO CHOLERA
gram negative
comma-shaped
aerobic or anaerobic bacillus with H antigen and O antigen
oxidase positive
sigle polar flagellum - CHOLERA TOXIN
in the small intestine - producing enterotoxin
very high infective dose is required 10^8
what is the EPIDEMIOLOGY OF CHOLERA ?
mostly in india
which SEROTYPE OF CHOLERA are the MOST PATHOGENIC AND LARGE OUTBREAKS CAUSING EPIDEMICS
V.Cholera O1 and O139
more than 200 serogroups of V cholerae have been identified, V cholerae
O1 and V cholerae
O139 are the principal ones associated with epidemic cholera
what is the TRANSMISSION OF VIBRIO CHOLERA
fecal oral
undercooked seafood or contaminated water
what is the PATHOGENESIS OF CHOLERA?
enterotoxin is a protein molecule composed of
5 B subunits and 2 A subunits.
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The B subunits are responsible for binding to a ganglioside receptor located on the surface of the cells that line the intestinal mucosa.
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The A1 subunit of cholera toxin activates adenylate cyclase
to cause a net increase in
cyclic adenosine monophosphate (cAMP)
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cAMP blocks the absorption of sodium and chloride by the microvilli and promote
the secretion of chloride
-
> water is
attracted into the intestinal lumen due to high osmolarity
what is the INCUBATION PERIOD FOR VIBRIO CHOLERA ?
0-2 days
however very high infective dose is required 10^8
what are the CLINICAL FEATURES FOR VIBRIO CHOLERA ?
low grade fever - no fever,
profuse rice water stools - not malodorous
vomiting appear later
muscle cramps due to electrolyte loss
DIAGNOSIS OF VIBRIO CHOLERA ?
Rapid cholera dipstick tests - low sensitivity and specificity
v.cholera detection with dark field microscopy
stool culture
serotype can be
discerned by immobilization with specific antiserum
TCBS culture agar (thiosulfate citrate bile salt sucrose) - flat yellow colony
Monoclonal antibody
– based diagnostic kits and methods based on PCR
and on DNA probes - for detection of V. cholerae
O1 and O139
- with stool sample
what is the TREATMENT OF VIBRIO CHOLERA ?
urgent fluid replacement
antibiotic therapy in severe cases - doxycycline ,
erythromycin in children
what are the COMPLICATIONS OF VIBRIO CHOLERA ?
severe dehydration
pneumonia
what is the PREVENTION OF CHOLERA ?
single dose live oral cholera vaccine = Vaxchora for 18-64 years old who travel in endemic areas
Four other oral
inactivated, or non-live
cholera vaccines
exist
ANTI EPIDEMIC MEASURES FOR CHOLERA ?
Make sure to drink and use safe water
Wash your hands often with soap and safe water
Use latrines or bury your poop; do not poop in any body of water.
Cook food well
