3. INTRODUCTION
CHOLERA
Cholera is an infection in the small intestine
caused by the bacterium called Vibrio
Cholerae
The word cholera is from greek : kholera from
khole “bile”and the word 𝓥𝓲𝓫𝓻𝓲𝓸 -Filippo pacini
isolated micro organism and he called it as
Vibrions from cholera patient
The main symptoms are watery diarrhea and
vomiting
Transmission occurs primarily by drinking water
or eating food that has been contaminated by the
5. MORPHOLOGY
• The vibrio cholera resembling letter “V”
• Its measures from : length -1.5 to 3.0 μm
breadth - 0.5 μm .
• It’s a curved or “comma – shaped” rod with rounded or
slightly pointed ends.
• Gram negative, non- sporing and non-capsulated .
•The vibrio is actively motile, and the movement is of a
“darting” type due to a single long terminal flagellum
• In liquid cultures the vibrios occur singly, in pairs, or in chains
end to end with the curves alternating presenting S-shaped
arrangement.
6. EPIDEMIOLOGY
According to WHO, During 19th Century, cholera spread across the
world from its original reservoir in the Ganges Delt in India.
Six subsequent pandemics killed million of people across all
contients.
The current (seventh) pandemic started in South Asia in 1971 and
the America in 1991
Cholera is now endemic in many countries.
7. HISTORY
The germ responisble for cholera was
discovered :
John Snow conducted pioneering investing on cholera
epidemics in england and particulary in london in 1854 in
which he demonstrated that contaminated water was the
key sources of the epidemics
The Italian physican, Filippo Pacini,work independtly in
Italy,in 1854,first observed comma shaped forms under a
microscope in cholera stools
In 1884,Robert Koch first isolated Vibrio Cholera in pure
culture in work that began in epypt and continued
Calcutta in India has favoring the germ theory over the
miasma theory of disease
8. CULTURE CHARACTERS
VIBRIO CHOLERAE IS AN AEROBIC
It grow at a temperature range of 16 ͦ-40 ͦ C, but the optimum temperature is 37 ͦ C
It grow on ordinary media having the Ph of 7.6 to 8 & will also grow at a Ph of 9 to 9.5
Colonies on agar occur after 12-24 hours of incubation
The colonies are moist ,translucent, regular discs,1-2mm in diameter, showing a
characteristics bluish colour in transmitted light
9. CONTINUED…..
MEDIA Uses
Alkaline peptone water Enrichment media for Vibrio cholerae
Alkaline Salt Transport
Medium
Taurocholate Peptone
Transport Medium
Liquid media by addition of
* Glucose (0.5 % to 1%)
* Ascorbic Acid (0.1%)
*Cysteine (0.1)%
*Sodium Merceptoacetate (0.1%)
* Thioglycollate ( 0.1%)
* Particles of cooked meat broth
Transport media for diarrheal diseases suspected of
being caused by V.cholerae
Anaerobic Media
10. CONTINUED…..
MEDIA Colony Morphology
Nutrient Agar The colonies are moist ,translucent
round disks(1-2mm in
diameter)with a blush tinge in
transmitted
Mac Conkey Agar The colonies are colorless at first
but become reddish on prolonged
incubation due to late
fermentation of lactose
Thiosulphate citrate bile sucrose
agar(Ph 8.6)
It is used as a selective medium for
isolation of vibrios.it produces
large yellow convex due to sucrose
fermentation.
11. BIOCHEMICAL REACTIONS
The cholera vibrios form acid without gas in glucose,maltose,sucrose and mannose in
1-2 days,but don’t ferment arabinose.
Indole is produed and nitrates are reduced to nitrate
Gelatin and serum are rapidly reduced
NH3 & H2S are formed
Reaction in the Voges Proskauer test are variable
12. ANTIGENIC CHARACTERS
The organism possesses both H and O antigens
Common heat labile flagellar H – antigen
O –lipopolysaccharide confers serlogic specificity
More than 150 O antigen serogroups
Only O-1 & 0139(polysaccharide capulse)
serogroups causes ,asiatic cholera
There serotypes ; Ogawa,Inaba,Hikojima
Two biovars ; Classic and EI T or hemolysin
13. SENSITIVITY
V - cholerae is killed at 56 ͦ C within 30 minutes.
On drying in sunlight , the organism dies within two or three hours.
In stagnant water with an alkaline reaction the organism may survive for a considerable
period . E.g., 5 -10 days or longer, but it probably does not multiply to any extent in such
water .
it is sensitive to sulphonamides, streptomycins chloramphenicol and the tetracyclines.
14. PATHOGENICITY
Cholera is an exclusively human disease acquired through contamination of water with V.cholerae.
This is in acute disease of sudden onset characterised by pofuse watery diarrhoea(rice watery stools),Vomitting, muscular cramps
and extreme collapse.
The vibrios multiply freely in the lumen of the small intestine and are present in large numbers in the intestial contents and dejecta.
The stools contain many white flakes consisting mostly and some epithelial cells,the “rice water stools”.
The organsims does not pentrate deeply in the bowel wall and practically never invades the blood stream .
The gall – bladder may be infected.
20. SUMMARY
Cholera is an extremly virulent disease transmitted through ingestion of contamission of food and wate
Cholera can cause sever acute watery diarrhoea and the severe forms of the disease can kill within
hours is left untreated
Prevention is mainly based on basic santiary and hygiene measures,newly developed oral vaccines
are under consideration for their use in public health
22. REFERENCE
Dr. CHANDRAKANTH KELMANI Ph.D.,Text of microbiology vol. IV, Edited by
Prof. S.B.SULLIA (PAGE NO 79 - 81).
Retrived from – https://www.cdc.gov/cholera/preventionsteps.html
https://www.slideshare.net/NikilVaishnav3/cholera-ppts
