about cholera a small ppt

1. Cholera
Harikrishna S
Group No:512

2. Learning Objectives
• Define cholera.
• State epidemiology of cholera.
• Describe the causative organism.
• Explain the pathophysiology of cholera.
• Mention the sign & symptom,
complication, risk factors, causes,
diagnosis, treatment, prevention, &
prognosis of cholera.
• Describe the ways of controlling the
spread of cholera.

3. Cholera
 Cholera is an acute diarrheal illness
caused by infection of the intestine
with the bacteria Vibrio cholerae.

4. Epidemiology
• Cholera was prevalent in the 1800s, but
due to proper treatment of sewage and
drinking water, has become rare in
developed countries.
• Cholera is a fecal disease, meaning that it
spreads when the feces of an infected
person come into contact with food or
water.
• Incidence: 1 in 100,000 worldwide.
• Over 1 million cases and nearly 10,000
fatalities.

5. Vibrio cholerae
• Gram negative.
• Type of Gammaproteobacteria
• Distinguishing factors: Oxidase-positive,
motile via polar flagellum, and both
respiratory and fermentative metabolism.
• Organism can multiply freely in water

6. Pathophysiology of cholera
V. cholerae
accumulates in
stomach
Produces toxins
Toxins will bind
to G-protein
coupled
receptor
Inactivation of
GTPase
G- protein stuck
in "on" position
increase cAMP
activation of ion
channels
NaCl influx into
intestinal lumen
to drag water
into lumen
lead to watery
diarrhea

7. Signs & Symptoms
 Most people remain asymptomatic. The symptoms of
cholera include :
profuse, watery
diarrhea
stomach
pains
leg cramps Mild fever
Vomiting Sunken eyes
and cheeks
Dry mucous
membranes
Decreased
urinary output

8. Complications
severe dehydration Shock
Renal failure Death

9. Risk Factors
• Rare in developed countries
• Common in Asia, Africa, & Latin
America
Poor sanitary
conditions
• Contaminated seafood, even in
developed countries.
• Especially shellfish.
Raw or
undercooked food
• People with low levels of stomach
acid
• Such as children, older adults, and
some medications.
Hypochlorhydria
• Reasons aren't entirely clear
• Twice more likely
Type O blood

10. Causes (transmission mode)
Drinking
contaminat
ed water
Eating raw or
undercooked
shellfish

11. diagnosis
Clinical diagnosis
Cholera should be
considered in all cases
with severe watery
diarrhea and vomiting.
Traveling to affected areas
and eating shellfish
No distinguishing clinical
manifestations for
cholera.
Differential diagnosis
Enterotoxigenic e. Coli
Bacterial food poisoning
Viral gastroenteritis

12. Laboratory Diagnosis
 CULTURE
• Vibrios often detected by
dark field or phase
contrast microscopy of
stool
• Organisms are motile,
appearing like “shooting
stars”
• Microscopy show sheets of
curved Gram negative
rods.
• When plated on sucrose
dishes, yellow colonies
appear confirming cholera
present

13. Laboratory Diagnosis
Additional methods of
detection include PCR and
monoclonal antibody-
based stool tests.

14. Treatment
Oral rehydration salts
• Up to 80% of cases can be treated through
this.
Intravenous fluids (Ringer lactate)
• For severe cases.
Antimicrobial Therapy
• can diminish duration of diarrhea, reduce
volume of rehydration fluids needed, and
shorten duration of V. cholerae excretion.

15. Prevention
• Basic health education and
hygiene
• Mass chemoprophylaxis
• Provision of safe water and
sanitation
• Comprehensive Multidisciplinary
Approach: water, sanitation,
education, and communication

16. Vaccines
Parenteral Vaccine :
• 2 doses administered 2 weeks apart
• Efficacy of approximately 50% and hardly exceeds 6 months
• Not recommended
Killed WC/rBS Vaccine :
• Killed whole-cell V.cholerae in combination with a recombinant
B-subunit of cholera toxin
• Safe in pregnancy and breastfeeding
• Efficacy of approximately 50% after 3 years
• Only mild side-effects
Live, attenuated CVD 103-HgR Vaccine :
• Protection as early as 1 week after vaccination, with >90%
• Unknown efficacy for children under 2
• No adverse side-effects

17. Prognosis
 The prognosis of cholera can range
depending on the severity of the
dehydration and how quickly the
patient is given and responds to
treatments.
 Death (mortality) rates in untreated
cholera can be as high as 50%-60%
during large outbreaks but can be
reduced to about 1% if treatment
protocols are rapidly put into action.

18. Controlling cholera
Treatment
centers Set up treatment centers for
prompt treatment.
Sanitary
measures. food safety and animal health
measures
Comprehensive
surveillance
data
(adapt to each situation) for a
comprehensive multidisciplinary
approach.

19. Thank you