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November 18, 2016
Global Efforts to Control Cholera
Background
material assistance and support to those Haitians most
Cholera is a severe diarrheal infection that is contracted by
directly affected by cholera. For more information on
ingesting food or water contaminated with the bacterium
cholera in Haiti, see CRS In Focus IF10502, Haiti:
Vibrio cholerae. The disease is found primarily in countries
Cholera, the United Nations, and Hurricane Matthew, by
without sufficient access to clean water, sanitation, and
Maureen Taft-Morales and Tiaji Salaam-Blyther.
hygiene. Cholera can also commonly be found in urban
slums and camps for internally displaced persons or
Industrialized countries virtually eliminated epidemic
refugees. About 75% of infected people do not exhibit
cholera in the late 19th and early 20th centuries, as municipal
symptoms, although they can spread the bacterium for up to
water treatment and sanitation networks were constructed
two weeks through food or water contaminated with their
and access to clean potable water was made readily
fecal matter. Others may experience acute diarrhea and
available. In other parts of the world, the absence of such
vomiting—symptoms that could lead to severe dehydration
resources contributes to the persistence of cholera. WHO
or death within hours if not immediately treated. Common
estimated that in 2015, 663 million people worldwide
treatments include oral rehydration salts and antibiotics.
lacked access to clean water and 2.4 billion people were
Cholera vaccines provide protection for three to five years.
without proper sanitation facilities.
The World Health Organization (WHO) estimates that each
year there are between 1 and 4 million cholera cases
Cholera and International Health
worldwide, which cause between 21,000 and 143,000
Regulations
deaths per year. People with suppressed immune
Experts are uncertain about precisely how many cholera
conditions, such as malnourished children and people living
cases occur annually. Studies indicate that less than 10% of
with HIV, are more likely to die from cholera. Congress
all global cholera cases are reported. Since the revised
supports global cholera control efforts through
International Health Regulations (2005) entered into force
appropriations for USAID, U.S. Centers for Disease
in 2007, countries are no longer required to “automatically
Control and Prevention (CDC), and multilateral
notify cases of cholera, plague, and yellow fever to WHO.”
organizations like WHO.
The revised reporting requirement may also contribute to
data gaps. Information on cholera cases is also challenged
Prevalence
by varied case definitions, uneven political will, and
Cholera cases are primarily found in sub-Sahara African
insufficient surveillance and diagnostic capacity.
and Southeast Asia (Figure 1). A number of countries
across central and eastern Africa are contending with
Cholera Vaccines
ongoing cholera outbreaks, and further outbreaks are
Prompted in part by the 2010 Haiti outbreak, the 64th World
expected as the El Niño weather pattern creates favorable
Health Assembly recommended the use of oral cholera
conditions for the spread of the disease. Inadequate access
vaccines (OCVs) in 2011 to help manage outbreaks. Two
to clean water and sanitation in parts of sub-Saharan Africa
years later, an international cholera vaccine stockpile was
and Southeast Asia complicates efforts to eliminate cholera.
established. WHO, Médicins Sans Frontières (MSF), the
With proper treatment, cholera case fatality ratios (CFR;
International Federation of Red Cross and Red Crescent
percentage of people with cholera who die) generally do not
Societies (IFRC), and the U.N. Children’s Fund (UNICEF)
exceed 1%. In 2015, 15 countries reported CFRs higher
jointly manage the stockpile. Countries can request OCVs
than 1%. These were Burma, Cameroon, Cote d’Ivoire,
during humanitarian crises, and vaccines are made available
Democratic Republic of Congo, Ghana, Iran, Malawi,
to areas where cholera is proven to be highly endemic. The
Niger, Nigeria, Somalia, South Sudan, Tanzania, Togo,
OCV global stockpile is complemented by the work of the
Uganda, and Zimbabwe. Although Haiti has consistently
Global Task Force on Cholera Control (GTFCC), an
reported the highest number of cholera cases and deaths in
international body comprising governmental and non-
the Americas, concerted efforts by the Haitian government
governmental organizations, which works to coordinate
and implementing partners have led to a decline in cholera
cholera control and treatment mechanisms throughout the
CFR from 2.2% in 2010 to 0.9% in 2015.
world.
In 2010, United Nations (U.N.) peacekeepers inadvertently
Outlook
introduced cholera into Haiti and caused the largest cholera
Demand for oral cholera vaccines has exceeded the quantity
outbreak to date. In 2015, Haiti reported 36,045 cholera
available through the WHO OCV stockpile. In 2015, for
cases—the second highest number of global cholera cases
example, WHO was unable to fill requests from Sudan and
(Afghanistan had the most with 58,064 cholera cases)—
Haiti for cholera vaccines. In January 2016, WHO
which accounted for 98% of cholera cases in the Americas
announced that it had approved a new manufacturer to
and 21% of global cases (Figure 2). The U.N. Secretary-
produce the OCV vaccine, which is expected to triple the
General is developing a package that would provide
OCV stockpile to 6 million doses.
https://crsreports.congress.gov
Global Efforts to Control Cholera
In an effort to prevent a cholera outbreak as severe as the
have contracted cholera. Hurricane damage to health
2010 outbreak in Haiti, WHO plans to test a new approach
facilities has hampered cholera control efforts.
in Haiti that would involve the administration of a single
vaccine dose. Standard guidelines call for OCV to be
Elsewhere, cholera control and elimination efforts are
administered in two doses. Health experts hope that single
undermined by conflict-induced displacement (increasing
dose administration of OCV is effective, as the strategy
the likelihood that people find shelter in informal
could double the amount of people who receive the vaccine.
settlements lacking clean water and sanitation) and weak
Cholera cases in Haiti have already risen in the aftermath of
water and sanitation systems in several countries
Hurricane Matthew: from October 2 through November 6,
worldwide.
2016, Haitian officials suspect that more than 5,840 people
Figure 1. Cholera Deaths and Imported Cases Worldwide: 2015
Source: WHO, Global Health Observatory, Map Gallery, Countries Reporting Cholera Deaths and Imported Cases in 2015, September 26, 2016.
Figure 2. Number of Cholera Cases Reported to WHO: 1989-2015
Source: Adapted by CRS from WHO, Weekly Epidemiological Record, September 23, 2016, Volume 91, Issue 38, pp. 433-440, p. 437.
Tiaji Salaam-Blyther, Specialist in Global Health
Edward Y. Gracia, Analyst in Latin American Studies
IF10508
https://crsreports.congress.gov
Global Efforts to Control Cholera
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