Transcript CHOLERA

CHOLERA
Presenter: Dr. J.J. Kambona
Friday, July 17, 2015
Case definition
• Cholera outbreak should be suspected
when a patient older than 5 years
develops severe dehydration or die from
acute, severe, watery diarrhoea. Or
• If there is a sudden increase in the daily
number of patients with acute watery
diarrhoea, especially patients who pass
‘rice-water’ stools typical of cholera.
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Systemic routine
1. Verification of the cholera.
2. Confirmation of the existence of the cholera epidemic.
3. Identification of the affected persons and their
characteristics.
4. Definition and investigation of the population at risk.
5. Formulation of a hypothesis as to source and spread of
epidemic.
6. Management of the epidemic.
7. Prevention of spread and commencement of control
measures.
8. Writing a report.
9. Continued surveillance of the population.
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1. Verification of the cholera
Once the epidemic is notified:
• Take the a detailed history from the
informants.
• Make a tentative differential diagnoses:
o Type of diagnostic specimen.
o Kind of equipments.
• Alert the laboratory which will process the
specimens.
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1. Verification of the cholera.....
• Special arrangement:
o Stakeholders meeting.
o Transport from the epidemic area at
awkward hours of the day or night.
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2. Confirmation of the existence of cholera
epidemic
• Obtain an approximate estimate of
previous incidence of acute watery
diarrhoea, both from clinics and
hospital data and by questioning the
local people.
• Demonstrate the existence of the
epidemic by a graph of incidence
against time and by mapping its
geographic extent.
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3. Identification of the affected persons and their
characteristics
A. Case histories:
Details of each confirmed or suspected case must be
taken in order to obtain a complete picture of the
epidemic.
• Name.
• Age.
• Sex.
• Occupation.
• Place of residence.
• Recent movements.
• Details of symptoms (including time of onset).
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3. Identification of the affected persons and their
characteristics.....
• The details of what they have been eating or
drinking , when and its source.
• Contact with a person with similar symptoms.
Record all information on specially prepared
forms.
If large numbers of cases (> 1,000) are involved
the data will require coding and analysis by
computer.
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3. Identification of the affected persons and their
characteristics.....
B. Search for addition cases.
• The initial notification may come from the
hospital, but visit:
o Dispensaries.
o Health centers.
• Further inquiry in the villages.
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4. Definition and investigations of the population at risk
A. Definition:
• Analyse case histories to get a profile of patients
characteristics.
• Epidemiological description:
Relate the profile to the characteristics and distribution
of the entire population at risk.
• Attack rates = Number of cases
population at risk
• If possible age/sex-specific attack rates should be
calculated.
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A.Definition.....
• Point source epidemic:
Compare the characteristics of the cholera
cases with those of people seemingly
exposed to cholera source but not
affected.
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B. Investigations
I.
•
•
Microscopic stool examination:
Direct: Vibrio cholerae are gram-negative and
curved (coma shaped) or straight bacillus.
Dark-field of the wet mount of fresh stool:
The organisms are mobile by means of a
single flagellum. It can be confirmed by adding
vibrio antisera, which results into cessation of
motility of only the homologous organism.
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Vibrio cholerae
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B. Investigations…..
II. Stool analysis:
Vibrio cholerae do not elicit an inflammatory
response and therefore, stool contains few
leucocytes and no erythrocytes.
III. Haematological tests:
• Full blood picture: Shows neutrophil
leucocytosis without a left shift when patients
are first observed.
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IV. Stool culture and sensitivity
Routine differential media:
A. Triple sugar iron agar:
Gives the non-pathogenic pattern of an acid (yellow)
slant, because of fermentation of sucrose contained in
the media.
B. Alkaline enrichment media:
•
Peptone water (pH 8.5-9.0).
•
Media containing bile salts e.g. thiosulphate–citrate
bile-sucrose agar (pH 8.6). Sucrose fermenting vibrio
cholerae grow as large, smooth, round yellow colonies
that stand out against the blue-green agar.
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4.
Formulation of a hypothesis as to source and
spread cholera
• Aims at knowing why, when and how the cholera
occurred.
• Establish changed relevant previous conditions
related the outbreak of cholera:
o Rains.
o Water supply.
o Sewage disposal.
o Refuse collection.
o Behavioural change.
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4.
Formulation of a hypothesis as to source and
spread cholera.....
• Establish the:
o Reservoir of vibrio cholerae.
o Mode of exit from this reservoir or
Source.
o Mode of transmission to the next host.
o The mode of entry.
o The susceptibility of the host.
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Treatment
• Look and establish cholera emergency
treatment centre.
• Look for additional staff and trained them
very rapidly. Health auxiliaries medical
students or even the army may be
available for this.
• Estimate the amount of drugs and other
medical supplies and order them urgently.
Treatment
•
1.
2.
3.
4.
5.
Treatment of cholera should start before the diagnosis
is confirmed.
Assess the dehydration and classify the degree of
dehydration.
Rehydrate the patient and monitor frequently. Then,
reassess hydration status.
Maintain hydration by replacing the ongoing fluid losses
until diarrhoea stops.
Administer oral antibiotics to the patient with severe
dehydration.
Feed the patient.
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Finding
Mild (3-5%)
Moderate (6-9%)
Severe (10%)
Pulse.
Rate, volume is
normal.
Rapid.
Rapid and weak.
Systolic pressure.
Normal.
Normal to low.
Low.
Respirations.
Normal.
Deep, rate may be increased.
Deep, tachypnoeia.
Buccal mucosa.
Tacky or slightly dry.
Dry.
Parched.
Anterior fontanelle.
Normal.
Sunken.
Markedly sunken.
Eyes.
Normal.
Sunken.
Markedly sunken.
Skin turgor.
Normal.
Reduced.
Tenting.
Skin.
Normal.
Cool.
Cool, mottled, acrocyanosis.
Urine output.
Normal or mildly
reduced.
Markedly reduced.
Anuria.
Systemic signs.
Increased thirst.
Listlessness, irritability.*
Grunting, lethargy, coma.*
Cholera cot
I.
Severe dehydration
 Ringer lactate is the fluid of first choice or
if not available, give isotonic sodium
chloride solution.
 Amount of IV fluid: 100 ml/kg in 3 hours:
• 30 ml/kg as rapidly as possible (within 30
minutes).
• 70 ml/kg in the next 2 hours.
• Re-assess the patient after 3 hours.
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II.
Moderate dehydration
• Give 75 ml/kg of ORS solution for the first
4 hours.
• If the patient passes watery stools or
wants more ORS solution than indicated,
give more.
• Discard the leftover solution after 24
hours.
• Re-assess the patient after 4 hours.
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III. Mild dehydration
– Give ORS packets to take at home, enough
for 2 days (2000 ml/day).
– Demonstrate to the patient or caretaker how
to prepare and give the solution.
– If diarrhoea stops, discharged patient should
return for follow-up in 2 days.
Most patients absorb ORS solution to
achieve hydration, even when they are
vomiting.
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III. Mild dehydration…..
Instruct the patient or the caretaker
to return if any of the following signs
develop:
• Increased number of watery stool.
• Marked thirst.
• Repeated vomiting.
• Any signs indicating other problems
e.g. fever or blood in stool.
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Oral antibiotics
•
•
•
•
Azithromycin 1 g PO stat. Or
Tetracycline 2 g PO stat. Or
Doxycycline 300 mg PO stat. Or
Ciprofloxacin 250 mg PO OD for 3 days
or 1 g stat (not to exceed 1 g/dose).
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Oral antibiotics…..
• Norfloxacin 400 mg PO bid for 3 days. Do
not to exceed 800 mg/day. Or
• Erythromycin 40 mg/kg PO divided TID for
3 days. Or
• Co-trimoxazole 960 mg PO BID for 3 days.
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Prevention
1. Early identification and case management.
2. Active surveillance and prompt reporting.
3. Water supply: Ensure a safe water supply
(especially for municipal water system).
4. Improve sanitation and sewage disposal.
5. Making food safe for consumption by thorough
cooking of high risk foods especially seafood
and protecting it against flies.
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Prevention…..
6. Health education through mass media:
Insisting on:
• Importance of purifying water and cooking
seafood.
• Washing hands after using the toilet and
before food preparation.
• Recognition of the signs of cholera and
location where treatment can be obtained to
avoid delays in cases of illness.
7. Cholera vaccine.
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Report writing and continued surveillance
• Categories of reports:
1. A popular account for laypeople.
2. An account for planners in the ministry of
health or local authority.
3. A scientific report for publication in a
medical journal.
• Continue surveillance of the population.
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Thank you for your
attention
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References
1.
2.
3.
4.
5.
Thaker V.V. Cholera. www.emedicine.com/ped/topic382.htm Last
updated May 1, 2006.
Todd W.T.A., Lookwood D.N.J., Nye F.J., Wilkins E.G.L and
Carey P.B. infection and immune failure (cholera); Davidson’s
principles and practice of medicine, 19th edition, chapter 1, page
44.
Sack D.A., Sack R.B., Nair G.B and Siddique A.K. Cholera; The
Lancet, January, 17, 2004. 363 (9404): 223-233.
Butterton J.R. Approach to the patient with vibrio cholerae
infection. www.UpToDate.com Version 13.1; Last updated:
January 27, 2004.
Barker D.J.P and Hall A.J. Investigation of epidemics; Practical
epidemiology.4th edition
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