Cholera Flashcards
Cholera Learning objectives
– Describe the causative agent for Cholera and
human exposure
– Describe infection and transmission
– Disease burden globally
– Disease burden in South Africa
– Describe risk factors for the disease transmission
– Methods for prevention and control
What is the Causative agent of Cholera?
The agent was first identified by Robert Koch in 1883
• Caused by a Gram-negative bacteria called Vibrio cholerae
• Survives in both fresh and saltwater
It has 200 serogroups.
A serogroup =a group of serotypes with similar but distinguishable serological reactions
The two Serogroups that cause epidemic
Two serogroups (O1 and O139) or types of Vibrio cholerae bacteria can produce cholera toxin that causes the disease we call cholera. About 1 in 10 people infected with cholera toxin-producing O1 or O139 Vibrio cholerae experience severe, life-threatening illness, and both serogroups can cause widespread epidemics.
Serogroups are further differentiated into serotypes Inaba or
Ogawai
O1 serogroup
• classical (highly virulent, with high mortality) – caused 2 major
pandemic waves
• El Tor (low virulence, as a result has greater spread)- responsible for
the 7th pandemic
The History of Cholera.
Cholera has its origins in the Bay of Bengal
• Earliest western record of Cholera epidemics dates
back to the 16th century with cases recorded in India
• Global pandemics of ‘‘Asiatic cholera’’ were first documented in 1817
• Occasional outbreaks in China due to trader contact
and in the Middle East due to the pilgrims
• Since 1817 it spread globally due to colonization, industrialization, military conflicts, and mass migration
The six pandemics of Cholera
from 1817 on and off till 1923
Cholera was the first disease that what?
- First disease for which modern public health surveillance, monitoring, and reporting was implemented in terms of the International Health Regulations.
- Several African countries (including South Africa) affected by Cholera.
The 7th Cholera pandemic
-Started in 1961 caused by
V. cholerae O1 El Tor
-Lower virulence of El Tor results in less severely ill, thus more
mobile, hosts capable of infecting others over a longer period of
time
• Spread across continents
• Major outbreaks in the past 40 years occurred in Peru in 1991,
The Soviet Union from 1961 onwards, and South Africa from August
2000
• This pandemic has persisted for 40 years and shows no sign of
abating
The Epidemiology of Cholera currently
• Occurs in tropical and sub-tropical climates of
the world
• Communities with poor access to water and
sanitation
• Majority of affected people live in Africa and
Asia
In Africa most outbreaks are caused by
El Tor serotype Inaba / Vibrio cholerae O1
No cases of O139 have ever been reported in Africa
Cholera in South Africa.
– March 1974- cases on the mines in eastern Gauteng
– 1978 – 3 tourists who contracted cholera locally
– 1980-1987, 25251 cases of cholera (serotype Inaba)
were bacteriologically proven (Gauteng, KZN)
– However, the majority of the cases isolated in the
2008/2009 outbreak in SA was serotype, Ogawa.
Cholera is Category 1 notifiable disease in South Africa. What does that mean?
It means that Cholera requires immediate reporting by the most rapid means
available upon diagnosis followed by a written or
electronic notification to the Department of Health within
24 hours of diagnosis by health care providers, private
health laboratories or public health laboratories;
– Reported to the National Institute of Communicable
Diseases
Cholera Modes of Trnasmission
• Faecal contaminated water or food is the most important source of infection
• Both symptomatic and asymptomatic people
secrete infective bacteria in their stool
• Cholera is communicable for as long as bacteria is secreted in stool
• Can be person-to-person transmission via:
– Contaminated water and food
– Contaminated cooked or uncooked fish
– Eating food or drinking water with contaminated hands.
Risk factors for Cholera.
- Demographics
- Socio-economics
- Water sources and availability
- Food
- Latrines
- Hygiene
- Social behavior
- Blood type
- Gastric acidity
- HIV
Social behavior, Blood type, Gastric acidity, HIV as risk factors for Cholera.
Social behavior
– Close contact with known case of cholera increase risk of infection
– Attending mass gatherings and funerals increased the risk for disease
• Blood type
– higher risk of symptomatic cholera among patients with blood group O
• Gastric Acidity
– Decreased acidity increases the risk for disease
– positive Helicobacter pylori immunoglobulin G was associated with risk of
cholera
• HIV
– Increased risk with HIV positivity
Food, Latrines, and Hygiene as risk factors for Cholera.
• Food
– Consuming partially cooked or raw food is a risk factor
– Consuming food outside of the home or from street vendors increased
risk of disease
– Drinking water from rivers with infestation increases the risk of disease
– Vitamin A deficiency is a risk factor
– Breastfeeding is protective
• Latrines
– Open defaecation and communal toilets increase the risk of disease
– Access to flush toilets decreases the risk of infection
• Hygiene
– Handwashing with soap and water decreased the risk of disease
– Washing all utensils before use decreases the risk
– Washing hands after using the toilet decreased the risk
– Bathing in water infested with cholera increases the risk
Demographics, Socio-economics and Water sources and availabity as Riak factors for Cholera.
• Demographics
– Variable information on age and sex. No strong evidence to suggest that anyone’s age group or sex is more affected than the other.
• Socio-economics
– Households from a lower socio-economic grouping are at greater risk of
getting the disease.
• Water sources and availability
– River sources and water stored in containers increase the risk of infection
– Having to walk distances to get water was associated with increased risk
– Chlorination of water decreases the risk of disease.
Cholera Symptoms and signs.
Untreated mortality can be as high as 50% amongst those who are
1, Painless watery diarrhea [rice water stool, with flecks of mucus]
2. Nausea and profuse vomiting may happen early in the onset.
3. Majority are febrile [kids more than adults]
4. Results in rapid dehydration
5. Muscle cramps, acidosis, peripheral vasoconstriction, and ultimately
renal and circulatory failure, arrhythmias, and death may occur if treatment is not given timeously.
infected,
#People infected with the agent are highly infectious- they
contaminate water and food sources with which they come into
contact with
What happens the V Cholerae gets i nto your body?
• Short incubation period (2-5 days / in a few hours)
• V Cholerae produces enterotoxins that damage the gastrointestinal
mucosa.
Diagnosis of Cholera
Mainstay is based on case definition and
laboratory diagnosis
• Case definition
– In an area where cholera is not known to be present you have a patient who develops severe dehydration or dies from acute
watery diarrhea
– In an area where there is an outbreak and a patient develops
acute watery diarrhea with /without vomiting
• Laboratory diagnosis
– Stool specimen confirming V. cholera O1 or O139
– Serogroup of Vibrio and antimicrobial sensitivity must
be collected.
Treatment of Cholera
• Rehydration is very important
– Oral rehydration solution (ORS) / IV fluids
• Antibiotic: Ciprofloxacin for 3 days
• Children ≤ 5 years should be given zinc (10-14 days)
• Feed as soon as possible. Breastfed children continue
feeding throughout the illness
• Discharge when
– No longer dehydrated
– Can take ORS
– No vomiting
NB: ineffective treatments: anti-diarrhoeal medication; sugar
drinks
ORAL CHOLERA VACCINE (OCV)
• Two oral doses (7-14 days apart) of OCV protect for at
least three years ( children <6 yrs give 3 doses)
• Average efficacy of about 58% and effectiveness of 76
% (lower in children < 5 yrs)
• Since 2013, 56 campaigns in 15 countries and more
than 13 million doses administered
• OCV stockpile has allowed for an increasing trend
toward cholera vaccine use in affected countries
• Effectively bridging emergency response and longer-term cholera control with a WASH focus
The two main objectives of Control and Prevention of Cholera
– Reduce transmission, morbidity and mortality
– Reduce mortality (CFR<1%) by ensuring access to
timely and good quality treatment
Global Task Force on Cholera Control (GTFCC)
established with aims of:
– Global Roadmap to 2030: Ending Cholera
– Aim is to reduce cholera deaths by 90%
– Focus is on
• Early detection and quick response to contain
outbreaks
• A targeted multi-sectoral approach to prevent cholera
recurrence
• An effective mechanism of coordination for technical
support, advocacy, resource mobilization, and
partnership at local and global levels
EARLY DETECTION AND RESPONSE TO
CONTAIN OUTBREAKS
• Early warning surveillance systems
– Confirmation of suspected cases
– Good laboratory culture and diagnostic capacity
– Monitoring outbreaks and tracking strains
• Pre-positioning stocks of essential supplies
– ORS, IV fluids, cholera kits, cold chain equipment
• Preparedness and implementation of water,
sanitation and hygiene (WASH) systems
• Community engagement
• Mass vaccine campaigns with OCV
• Preparedness of the health care system,
– set-up of dedicated health care facilities (Cholera Treatment Centers
(CTCs) and Cholera Treatment Units (CTUs)) and training of HCWs [health care workers]
BASIC WASH PACKAGE
• Basic water supply: access to safe drinking water sources
(either household connection, public standpipe, borehole, protected dug
well, protected spring, or rainwater collection) within a 30-minute round-trip
plus household or other disinfection
• Basic sanitation: access to improved sanitation facilities
(connection to a public sewer, connection to a septic system, pour-flush
latrine, simple pit latrine, ventilated improved pit latrine)
• Basic hygiene: access to a hand-washing station with soap and
water for every household
• Community engagement to manage WASH resources and
to promote safe hygiene practices
COMMUNICATION WITH PUBLIC [about an outbreak]
• Media plays a very important role in
communicating with the public to get messages
out to the public.
– Radio, television, posters, newspapers and public
talks (schools, grant days, churches, clinics)
– Clear and precise messages
– Adapt messages to social, cultural and economic
circumstances of target communities ( example
chlorine / soap may not be affordable)
Messages To The Public
• Drink safe water
• Purify water- 5mls chlorine in 20-25 litres of water mixed and
allowed to stand for at least 2 hrs (preferably overnight) before
use
• Safe disposal of human waste – do not contaminate water
sources
• Do not eat contaminated / uncooked / partially cooked food ·
• Foods of vegetable origin should be peeled or shelled
• Boil milk and water before drinking
• Breastfeed babies where possible
• Go to a health facility if you have watery diarrhoea.
• Follow national guidelines for burial/ cremation of the deceased
FOOD SAFETY
• Environmental Health Practitioners important to
monitoring food safety in restaurants and street
vendors
• Health education should include
– Exclude infected persons from food preparation
– Prepare food under hygienic conditions
– Wash fruit and vegetable with clean water
– Cook food thoroughly and eat when hot
– Prevent contamination of food by flies or infected water
– Wash hands after using the toilet and prior to preparing food
– Do not eat from a communal container
– Reheat leftover food
Prevention of disease occurrence by targeting multi-sectoral interventions in cholera hotspots includes:
• Identifying of hotspots requiring priority action and
analysis of local transmission pattern.
• Implementing a package of selected effective
control measures adapted to the local transmission
pattern
• Identifying of hotspots requiring priority action and analysis of local transmission pattern.
– Accurate morbidity, mortality and environmental data on cholera
– Risk and vulnerability assessment in hotspots
– mapping of existing safe water sources, sanitation systems,
capacities for surveillance , existing isolation treatment facilities and
quality of health service delivery, and community engagement.
• Implementing a package of selected effective control measures adapted to the local transmission pattern.
– Strengthening surveillance, health systems
– Sustaining WASH
– Large scale Oral Cholera vaccination
– Community participation and cross-border collaboration
An effective mechanism of coordination for technical support,
resource mobilization, and partnership at local and global levels.
• Nationally-led cross-sectoral cholera control
programs
– Each country must have a national program
– Multi-sectoral action must be led by national
governments of cholera-affected countries
• The GTFCC as a strong coordination platform
– goal of the GTFCC is to support national and inter-country capacities by providing a strong platform for
advocacy and communications, fundraising, inter-sectoral coordination, and technical assistance.
What is meant by GTFCC?
Global Task Force on Cholera Control.
