managing infectious hazards
TRANSCRIPT
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Learning objectives
Describe the case definition and alerts for cholera
Describe main transmission routes
List the key preventive actions
Explain how cholera control is multisectoral
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The disease
Cholera is caused by the bacterium Vibrio cholerae.
It causes diarrhoea that can lead to severe dehydration and death in people of all ages.
Untreated, the case fatality can be as high as 50%.
80% of all infected cases will only have mild or no symptoms at all.
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History
Cholera can cause explosive, widespread epidemics.
Humans carry and spread the disease globally. We are currently in the 7th pandemic. Cholera arrived in Africa in 1971.
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Epidemiology
Transmission via faeco-oral route, contaminated water and food
There are three epidemiological profiles:
Epidemic
Humanitarian crises
Endemic
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Signs and symptoms
Acute watery diarrhoea with or without vomiting
Dehydration
May also cause hypoglycaemia, hypokalaemia
High risk of fetal loss in pregnant women with cholera (aggressive rehydration current best practice)
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Diagnosis and treatment
Clinical; action can begin
Rapid diagnostic tests to reinforce suspicion of epidemic
Stool culture for confirmation
Polymerase Chain Reaction (PCR) for confirmation
Diagnosis:
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Diagnosis and treatment
No or some signs of dehydration
Rehydrate with Oral Rehydration Salts (ORS)
Severe dehydration
IV rehydration with Ringer’s Lactate.
Antibiotics will help reduce severity and duration of disease
Treatment
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Prevention
Provide access to clean water
and sanitation
Adopt hand washing and other
protective hygiene practices
Engage communities
Provide treatment structures and
services
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Vaccination
Oral Cholera Vaccine (OCV)
Shanchol™ and Euvichol®
1 or 2 doses of vaccine given to
at risk populations above age 1
Protection approximately 80% at
6 months, 65% at 3 years
Longer duration of protection with
2 doses
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Accessing vaccine
Global OCV Stockpile to facilitate access to vaccine
For emergencies (outbreak response and humanitarian crises) vaccine available via the International Coordinating Group (ICG)
For integration in control programme for endemic areas vaccine available via the Global Task Force on Cholera Control (GTFCC) OCV working group
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Case definitions
a patient aged 5 years or more presenting with acute watery diarrhoea (AWD) and severe dehydration or dies from AWD
Non-endemic area
any patient aged 2 years or more presenting with AWD or dies from AWD
any patient presenting with AWD or dies from AWD
Endemic areas Epidemic area
Note: children under 5 are
susceptible to cholera and
must be treated accordingly
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Alerts
A death from AWD in a patient aged 5 years or more
A positive rapid diagnostic test
Alerts
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Alerts
A cluster of cases of AWD in patients aged 5 years or more in the same week and from the same area
A doubling of cases of AWD in patients aged 5 years or more compared to the previous week, for two consecutive weeks, in the same geographic area
Alerts
Note: in endemic areas, the
age limit used is 2 years
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Preparedness in identified high risk areas with multisectoral plans using measurable indicators including: surveillance (epidemiological and laboratory), case management, WaSH and vaccination
Rapidity and coordination of multisectoral response
Prevention and control
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Need for analysis of data and anticipation of spread of epidemics
Laboratory capacity for confirmation is weak in many countries and should be reinforced
Key concerns
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WHO technical support and recommendations
Cholera Coordination Mechanism (CCM) is providing a coordinated effort from everyone in emergencies to control cholera.
The Global Taskforce for Cholera Control (GTFCC) is providing a multisectoral platform for coordination and guidance for cholera control.
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WHO technical support and recommendations
New OCV Strategic Advisory Group of Experts on Immunization (SAGE) recommendations expected later this year
New Global WHO Strategy in development looking beyond outbreak response to long term cholera control
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WHO global strategy for cholera control
Eliminate predictable cholera epidemics
Respond to unpredictable epidemics
Reduce the magnitude and severity of cholera during humanitarian crisis
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WHO global strategy for cholera control
Cholera occurrence can be predicted in many settings
Be «pre-emptive»
Cholera is unevenly distributed
Focus on «hot spots»
The long term solution for cholera control is not in the health sector
Be multisectoral
Use OCV for large scale
Immediate impact
Trigger mechanism for long term control
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Research and development
Areas of research on OCV, 1 vs 2 dose regimens, dose spacing and out of cold chain use
Continued work on WaSH practices e.g. reduction of transmission in high risk households
Moving from response to control: identifying best practices, strategies
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Key contacts
Vincent Sodjinou: [email protected] (AFRO Focal Point)
Dominique Legros: [email protected] (Focal point)
David Olson: [email protected] (CCM and Outbreaks)
Lorenzo Pezzoli: [email protected] (OCV)
Kate Alberti: [email protected] (Capacity building)
Johanna Fihman: [email protected] or [email protected]
Photo credits:
WHO/C. Black; WHO/AMRO; WHO/E. Soteras Jalil; WHO/F. Thompson; WHO/L. Pezzoli