ONE OF THE TROPICAL DISEASES

1. CHOLERA BY JAMES NYIRENDA

2. DEFINITION
Cholera is an acute infectious disease
caused by vibrio cholerae characterized
by copious rice water diarrhoea,
vomiting, muscle cramps, severe
dehydration and vascular collapses.

3. INCUBATION PERIOD
From few hours to 5 days

4. TRANSMISSION
Oral faecal route through ingestion
of contaminated food and water.

5. CAUSATIVE ORGANISM
Cholera is caused by vibrio cholerae.
There are two (2) bio-types namely:
Classical cholerae vibrio
Haemolytic el-tar vibrio

6. CHARACTERISTICS OF VIBRIO
CHOLERAE
Comma shaped
Aerobic
Gram negative
Non spore forming

7. .
Motile organism (possess both flagella and
somatic antigens)
Killed by heat at 55oC for 15 minutes and by
phenolic and hypochlorite disinfectants
Can survive aquatic environments for extended
periods in a ‘dormant state’

8. EPIDEMIOLOGY
Cholera is a disease of low socioeconomic
groups living in unsanitary conditions with poor
health services, unsafe water supply, inadequate
or absent sewage disposal. It is common in Asia
and Africa. Infection spread from contaminated
feaces and water. Other portable foods include
milk, cold cooked foods and unwashed fruits
and vegetables

9. PATHOGENESIS:
The vibrio cholerae remain in the gut and does
not penetrate into the blood stream. It adheres to
the mucosa of the small intestines by both outer
membrane protein and flagella adhesions. Vibrio
cholerae produces enterotoxin that causes
excessive fliud and electrolyte loss. Sodium
Chloride absorption is inhibited and therefore
excreted resulting in water, sodium chloride, and
potassium and bicarbonate loss.

10. .
Immunity to both cholera toxin
and bacterial surface antigens
follows natural infection.

11. SIGNS AND SYMPTOMS
Evacuation phase
Mild to acute onset of diarrhoea which initially
contains faecal matter but later becomes
waterly, with flecks of white described as rice
water stool.
Projectile vomiting may be present
Severe dehydration due to diarrhoea and
vomiting

12. .
Collapse phase
Muscle cramps due to loss of
electrolytes
Metabolic acidosis indicated by
signs of air hunger with deep
sometimes rapid breathing.

13. .
Hypovolaemic shock due to vascular
depletion leading to vascular collapse
detected by hypotension, tachycardia, and
pulse may be impalpable at the wrist, cold
clammy skin, olyguria. If no intervention
shock can complicate into acute renal
failure and death

14. .
Recovery phase
Patient improves and the signs and
symptoms decline

15. DIAGNOSIS
In epidemics, presumptive diagnosis is
made on clinical presentation or
epidemiological grounds. Example, a
patient 5 years or older, who develops
acute watery diarrhoea with or without
vomiting residing in an area where cholera
is likely to occur.

16. LABORATORY DIAGNOSIS
Dark field microscopy of stool may show the
characteristic darting movement of vibrio.
Inhibition of movement by 01 antisera
provide strong evidence
Stool or vomitus or rectal swab for
microscopy, culture and sensitivity confirms
the diagnosis

17. .
Immunoflorecent allows for rapid
diagnosis

18. MANAGEMENT
Aims of management
To correct fluid and electrolyte imbalance
To eliminate the causative organism
To prevent the spread of infection
To prevent complications due to loss of
fluid and electrolytes

19. THERAPY
Correction of fluid and electrolyte
imbalance: Start intravenous
infusion of fluids such as Ringer’s
Lactate or normal saline
immediately. (Give ORS while setting
up the drip if patient is able to
drink).

20. .
In severe dehydration, give 30mls/kg body
weight in the first 30 minutes rapid I.V. then
70mls/kg body weight in the next 2½ hours.
The aim is to restore normal hydration and
acid-base balance within 2-3 hours.
Continue rehydrating the patient at a slower
rate until the pulse and BP return to normal.
When the patient can drink orally, give
5mls/kg body weight/hour (250mls/hr).

21. .
Monitor vital signs every 30
minutes. If signs of circulatory
overload are detected, slow down
the rate of flow. Monitor urine
output every hour (normal is 30-
40mls/hy). If less patient has
acute renal failure. Give ORS as

22. .
Maintain the patient on fluid by
equal amount from stool losses. In
this case oral rehydration is as
required may be done.

23. ANTIMICROBIAL AGENTS
Tetracycline
Doxycycline
Cotrimoxazole
Ciprofloxacin
Erythromycin

24. COMPLICATIONS
Paralytic ileus
Muscle weakness
Cardiac arrythymias
Renal failure

25. .
Metabolic acidosis
Hypoglycaemia
Pulmonary oedema

26. PREVENTION AND CONTROL OF
CHOLERA
Proper disposal and treatment of the germ
infected fecal waste (and all clothing and
bedding that come in contact with it)
produced by cholera victim is of primary
importance
Sewage: treatment of general sewage before
it enters the waterways or underground
water supplies prevent possible undetected

27. .
Sources: warnings about cholera
contamination posted around contaminated
water sources with directions on how to
decontaminate the water
Sterilization: boiling, filtering, and
chlorination of water kill the bacteria
produced by cholera patients and prevent
infections, when they do occur, from
spreading. All materials (clothing, bedding,
etc.) that come in contact with cholera

28. .
Hands etc. that touch cholera patients or
their clothing etc. should be thoroughly
cleaned and sterilized. All water used for
drinking, washing or cooking should be
sterilized by boiling or chlorination in any
area where cholera may be present.

29. .
Improve water supply and
sanitation
Contact tracing
Personal hygiene
Postpone festivals and gatherings

30. .
Change of attitudes/behaviours e.g. wash
hands, boil water, heat food before eating,
use toilet or latrine
Adequate treatment of cases
Active reporting of suspected cases in
areas previously uninfected (notification).