Cholera is an infectious disease caused by Vibrio cholerae bacteria that leads to severe watery diarrhea and dehydration. The bacteria is transmitted by ingesting contaminated water or food. Cholera toxins produced by the bacteria cause increased cyclic AMP levels that inhibit sodium absorption and activate chloride secretion in the intestines, resulting in a massive loss of fluid and electrolytes from rice water stools. Treatment involves oral rehydration and antibiotics which play a minor role in treating the infection.

1. Cholera
• Cholera is an
infectious disease that causes severe
watery
diarrhea ,
which leads to
dehydration .
•
Caused
by Vibrio cholerae
11
-
Curved
gram
-
ve bacilli
-
Motile
-
Single polar flagella
Classification :
Pathogenesis :
•
V. cholerae is transmitted
by ingestion of contaminated
water or
food .
•
Infective dose 108 bacilli (extremely acid -
labile )

2. Cholera Toxins :
• The toxin molecule consists of two peptide fragments
- A & B
A causes ADP
ribosylation of G- protein >
upregulates
the
activity of Adenylate cyclase → A CAMP .
B Binds to GMI
ganglia side receptors .
•
Increase in CAMP leads to :
(a) Inhibition of absorptive sodium transport system
in villus cells & activates
secretory chloride
which leads to Nacl in lumen .
(b) Inla ten moves
passively into bowel lumen .
(c) loss
of fluid &
electrolytes leads to shock &
acidosis .

3. •
Massive Diarrhea Non -
inflammatory diarrhea
Rice water stools
Resembles Arsenic metal
poisoning
Clinical Manifestations :
( Incubation period = 24-48
hrs)
• V. cholerae 01 00 0139
infections produce a
range of
clinical
manifestations such as :
(a)
Asymptomatic infection ( 75% cases )
(b) Mild diarrhea or cholera ( 20% cases )
(c) Sudden onset
of explosive &
life -
threatening diarrhea
( cholera
gravis ,
in 5% cases)
• Common manifestations :
(a)
lnlatery diarrhea
(b) Rice
watery stools .
(c)
Vomiting
(d) Abdominal Pain

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laboratory Diagnosis :
( is
Transport media - YR ( Venkatraman Ramakrishnan
)
Media
-
Cary - Blair Medium
ciii Enrichment Media -
Alkaline
Peptone water .
ciii, selective media -
T CBs ( Green to Yellow )
Treatment :
ii. Fluid
replacement
cii, Antibiotics (minor role)
Is
Doc = Macrolides ( Azithromycin or
Erythromycin )
C