introduction introduction introduction.ppt

Introduction

1. NeonateNeonate

4. BACKGROUND
Cholera, is a Greek word, which means the
gutter of the roof. It is caused by bacteria vibrio
cholerae
V cholerae is adiverse species includes
pathogenic and non pathogenic.
Cholera is classifed serologically of over 200
serological groups only 2 (V.choleraO1 and
O139) have caused cholera epidemics

5. The organism is a comma-shaped, gram-
negative, aerobic bacillus whose size varies from
1-3 mm in length by 0.5-0.8 mm in diameter.
V CHOLERAE
Its antigenic structure consists of a flagellar H
antigen and a somatic O antigen. It is the
differentiation of the latter that allows for
separation into pathogenic and nonpathogenic
strains.

7. RESERVOIR OF INFECTIONRESERVOIR OF INFECTION
Human is the only known reservoir of Human is the only known reservoir of
cholera infectioncholera infection
The ratio of severe cases to mild ones is The ratio of severe cases to mild ones is
shown to be 1:5 for classical type & 1:25 shown to be 1:5 for classical type & 1:25
for EL Torfor EL Tor

11. EpidemiologyEpidemiology
Cholera is vastly underreportd Cholera is vastly underreportd so cases of so cases of
mortality and morbidity to it are lackingmortality and morbidity to it are lacking
However there are an estamitedHowever there are an estamited
33 million cases and about100000million cases and about100000
deaths worldwide caused by V.cholera deaths worldwide caused by V.cholera
annuallyannually


12. O0\kO0\k

13. ClassificationClassification

14. EpidemiologyEpidemiology
At the end of 2016 and middle of At the end of 2016 and middle of
2017 two rapidly outbreaks occurred in 2017 two rapidly outbreaks occurred in
yemen yemen and were the world;s worst and were the world;s worst
cholera outbreak to date , with 500000 cholera outbreak to date , with 500000
cases of suspected cholera and 2000 cases cases of suspected cholera and 2000 cases
associated fatalities only in 4 monthsassociated fatalities only in 4 months



15. MECANISM :-
• Cholera is a toxin- mediated disease
•These toxins acts on the small intestine
• To reach the small intestine, the organisms has
to overcome the defense mechanisms of the
GIT (acidic media in the stomach)

PATHOGENESIS

16. PATHOGENESIS/2
They secrete certain mucinase which
help it to move rapidly through the
mucus
They also depend on the large
inoculums size (so they bypass the
gastric acidity)
Then got adherent to the epithelial
surface, probably by certain factor

17. PATHOGENESIS/4
The H toxin acts by activating The H toxin acts by activating
adenylecyclase, this activation leads to adenylecyclase, this activation leads to
rise in the level of the so called 3, 5-rise in the level of the so called 3, 5-
adenosine monophosphate (cAMP)adenosine monophosphate (cAMP)

18. PATHOGENESIS/5
This substance inhibits the absorptive This substance inhibits the absorptive
sodium transport & activates the sodium transport & activates the
excretory chloride in the intestinal cell→ excretory chloride in the intestinal cell→
accumulation of NaCl in the intestinal accumulation of NaCl in the intestinal
lumenlumen
This high osmolality is balanced by
water secretion, the result is watery
diarrhea
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19. Fluid loss originates in the duodenum and
upper jejunum; the ileum is less affected.

The colon usually is in a state of absorption
because it is relatively insensitive to the toxin.
PATHOGENESIS/6

20. PATHOGENESIS/5
The large volume of fluid produced in the
upper intestine, however, overwhelms the
absorptive capacity of the lower bowel,
which results in severe diarrhea
The enterotoxin acts locally & does not
invade the intestinal wall. As a result few
WBC & no RBC are found in the stool.

22. TRANSMISSION
Cholera is transmitted by the fecal-oral route
through contaminated water & food.
The infectious dose of bacteria required to
cause clinical disease varies with the source. If
ingested with water the dose is in the order of
10
3
-10
6
organisms. When ingested with food,
fewer organisms are required to produce
disease, namely 10
2
-10
4
.

24. Cholera has 2 main reservoirs, man & water.
Animals do not play a role in transmission of
disease.
V cholerae is unable to survive in an acid
medium. Therefore, any condition that reduces
gastric acid production increases the risk of
acquisition.
TRANSMISSION/2

25. RESERVOIR OF INFECTIONRESERVOIR OF INFECTION
Human is the only known reservoir of Human is the only known reservoir of
cholera infectioncholera infection
The ratio of severe cases to mild ones is The ratio of severe cases to mild ones is
shown to be 1:5 for classical type & 1:25 shown to be 1:5 for classical type & 1:25
for EL Torfor EL Tor

26. THANKS FOR YOUR
ATTENTION
roe

30. V. CHOLERAE