Cholera is an acute diarrheal infection caused by the bacterium Vibrio cholerae, typically transmitted via contaminated food or water. The disease is characterized by profuse watery diarrhea, and without treatment, it can lead to dehydration and severe complications such as hypovolemic shock. Effective management includes fluid replacement, electrolyte replenishment, and preventive measures like improved sanitation and vaccination.

1. Cholera
Eperu Jacob
BNS IV
26th February 2024

2. Learning objectives
• By the end of this session, the learner
should be able to:
– Define cholera and state its causative agent
– Discuss the epidemiology of cholera
– Describe the pathophysiology and clinical
manifestations of cholera
– Describe the management of cholera
– Describe the complications of cholera
– Describe the prevention of cholera

3. Cholera
• Definition
– Cholera is an acute diarrheal infection caused by
ingestion of food or water contaminated with the
bacterium vibrio cholerae.
– Vibrio cholerae is a comma shaped gram
negative aerobic or facultatatively anaerobic
bacillus.
– Its antigenic structure consists of a flagella H
antigen and somatic O antigen .
– Differentiation of pathogenic strains is dependent
on the O antigen.

4. Strands
• be classified into different serogroups
based on the structure of their O antigens
– Vibrio cholerae O1.
• This serogroup is further divided into two biotypes:
classical and El Tor. Each biotype can be further
classified into two serotypes based on the
structure of the O antigen: Inaba and Ogawa. The
classical biotype was responsible for earlier
pandemics, while the El Tor biotype is associated
with more recent outbreaks.

5. – Vibrio cholerae O139:
• This serogroup, also known as Bengal cholera,
emerged in the Indian subcontinent in the 1990s
as a result of genetic recombination between V.
cholerae O1 strains and other Vibrio species.
• It is characterized by its ability to cause cholera-
like illness despite lacking the classical O1
serogroup antigens.

6. Vibrio cholerae

7. Epidemiology
• A global estimate of 1.3 to 4 million people
get cholera each year and 21,000 to
143,000 people die from it. (WHO, 2023)
• People who get infected my may range
from no symptoms to severe states

10. Pathophysiology
• Transmitted by fecal oral route
• V. cholerae bacteria reach the small
intestine, where they colonize and adhere
to the mucosal surface, initiating infection
• V. cholerae produces several virulence
factors, with cholera toxin being the most
notable.

11. • Cholera toxin is an AB toxin consisting of
two subunits:
– The A subunit (active enzymatic component)
and the B subunit (binding component).
– The B subunit facilitates the entry of the toxin
into intestinal epithelial cells by binding to
specific receptors, such as GM1 ganglioside
receptors.

12. • Once inside the intestinal epithelial cells,
the A subunit of cholera toxin modifies a
regulatory G protein (Gs) by ADP-
ribosylation.
• This modification locks the Gs protein in its
active state, leading to continuous
activation of adenylyl cyclase.
• Adenylyl cyclase catalyzes the conversion
of ATP to cyclic AMP (cAMP), resulting in
elevated intracellular cAMP levels.

13. • Increased cAMP levels activate protein
kinase A (PKA), which phosphorylates and
activates the cystic fibrosis
transmembrane conductance regulator
(CFTR) channel.
• Activated CFTR channels facilitate the
secretion of chloride ions (Cl-) into the
intestinal lumen.
• Additionally, PKA inhibits sodium absorption
channels, reducing sodium reabsorption.

14. • The net effect is an efflux of chloride ions
and water into the intestinal lumen, leading
to watery diarrhea characteristic of
cholera.

16. Clinical manifestations
• The hallmark symptom of cholera is profuse,
watery diarrhea often described as "rice-
water stool."
• Signs of dehydration and electrolyte
imbalances, including hyponatremia,
hypokalemia, and metabolic acidosis.
• Dehydration manifests with symptoms such
as thirst, dry mucous membranes, sunken
eyes, decreased urine output, tachycardia,
and hypotension.
• In severe cases, dehydration can progress to
hypovolemic shock and death if untreated

17. Diagnosis
• History taking
• Physical examination
• Isolation and identification of v. cholerae in
stool cultures.

18. Management
• This can be categorized into two:
– Medical management
– Nursing management
• The goal of management is to replace the
lost fluids and get rid of the
microorganism.

20. Nursing management:
• Nursing concerns:
– Dehydration
– Loss of appetite
– Lethargy

21. Nursing diagnoses
• Imbalanced nutrition less than body
requirement related to loss of food
components in diarrhea evidenced by loss
of weight.
• Deficient fluid volume related to fluid loss
in watery diarrhea evidenced by sunken
eyes.

22. Nursing interventions
• Assessment of frequency and volume of
diarrhea
• Rehydration therapy
• Electrolyte replacement
• Infection control by isolation
• Nutritional support- small frequent meals
• Patient education
• Psychological support

23. Complications of cholera
• Hypovolemic shock
• Renal failure
• Cardiac arrhythmias
• Respiratory failure- due to metabolic
acidosis
• Secondary infections
• Neurologic complications as seizures

24. Prevention
• Improved water and sanitation
infrastructure
• Promotion of hygiene- hand washing
• Surveillance and early detection
• Vaccination- oral cholera vaccines
• Health education of communities
• Response and preparedness

25. References
• Herrington, DA , Hall, RH , Losonsky, G , Mekalanos,
JJ , Taylor, RK , and Levine, MM . Toxin, toxin-
coregulated pili, and the toxR regulon are essential for
Vibrio cholerae pathogenesis in humans. J Exp Med.
(1988) 168:1487–92. doi: 10.1084/jem.168.4.1487
• Kirn, TJ , Lafferty, MJ , Sandoe, CMP , and Taylor, RK
. Delineation of pilin domains required for bacterial
association into microcolonies and intestinal
colonization by Vibrio cholerae. Mol Microbiol. (2000)
35:896–910. doi: 10.1046/j.1365-2958.2000.01764.x

26. THANK YOU