Risk Factors Early in the 2010 Cholera Epidemic, Haiti.docx

Risk Factors Early
in the 2010 Cholera
Epidemic, Haiti
Katherine A. O’Connor, Emily Cartwright,
Anagha Loharikar, Janell Routh, Joanna Gaines,
Marie-Délivrance Bernadette Fouché,
Reginald Jean-Louis, Tracy Ayers,
Dawn Johnson, Jordan W. Tappero,
Thierry H. Roels, W. Roodly Archer,
Georges A. Dahourou, Eric Mintz, Robert Quick,
and Barbara E. Mahon
During the early weeks of the cholera outbreak that
began in Haiti in October 2010, we conducted a case–
control study to identify risk factors. Drinking treated water
was strongly protective against illness. Our results highlight
the effectiveness of safe water in cholera control.
On October 19, 2010, the Haitian Ministry of Public Health and
Population (MSPP) was notifi ed of
increased cases of acute watery diarrhea resulting in death
among adults in Artibonite Department. Within 2 days,
MSPP’s Laboratoire National de la Santé Publique had
identifi ed toxigenic Vibrio cholerae O1, serotype Ogawa,
biotype El Tor in stool specimens (1). The fi rst reports of
illness consistent with cholera occurred on October 16,
and, by November 19, cholera had reached all 10 Haitian
administrative departments (2).

Because the fi rst cases were in persons who worked
near the Artibonite River, contaminated river water was
suspected as the initial source. In a proactive effort to
protect the population, MSPP rapidly implemented a
cholera prevention campaign that began on October 22,
2010, to discourage the population from drinking river
water, distribute water treatment products, and promote
water treatment, handwashing, sanitation, and safe food
preparation. To inform further prevention activities, we
conducted a case–control study during the second and
third weeks of the outbreak to identify risk factors for
symptomatic cholera.
The Study
This study was conducted in Artibonite Department
close to where the fi rst cases were identifi ed. On the
basis of detailed hypothesis-generating interviews with
patients and known risk factors associated with cholera
in other investigations in the Americas, we created a
questionnaire to assess multiple exposures, including
river and other water-related exposures, sanitation and
hygiene practices, foods, and other factors. We enrolled
and interviewed participants from October 31 through
November 13, 2010, with a 4-day break during November
5–8 because of Hurricane Tomas. To rapidly generate
relevant information to guide outbreak response, we set
a goal of enrolling 50 case-patients and 100 controls, a
sample size that, although limited, was in line with that of
previous successful emergency investigations.
Eligible case-patients were persons >5 years of age
who were hospitalized between October 22 and November
9 for acute watery diarrhea at the Médecins Sans
Frontières cholera treatment unit in Petite Rivière, a town

in a densely populated rural region near the Artibonite
River. Only case-patients with the fi rst case of acute
watery diarrhea in their household since October 16 were
eligible. Case-patients were interviewed about exposures
during the 3 days before illness onset. Within 72 hours of
the interview, we visited case-patients at home, where we
observed household drinking water sources and storage
containers, presence of water treatment products, access
to toilet facilities, and the case-patient’s handwashing
technique. Drinking water was tested for free chlorine as
an objective measure of chlorine treatment. Matching by
neighborhood (through a systematic door-to-door search
from the case-patient’s house) and age group (5–15,
16–30, 31–45, and >46 years), we enrolled 2 controls
per case-patient at the time of the visit to case-patients’
homes from households with no diarrhea since October
16. We interviewed controls about exposures during the
same 3 days as the matched case-patient and made the
same household observations.
The term “improved drinking water source” indicated
it met the World Health Organization defi nition, which
describes technologies that protect water from outside
contamination (3). “Lacking safe water storage” referred to
water stored in an open container or bucket without a tap.
“Proper handwashing technique” was defi ned as observed
use of soap and thorough lathering.
We performed descriptive statistical analysis and exact
conditional logistic regression to compute the most likely
estimate or, when small cell sizes required, the median
unbiased estimate of matched odds ratios (mORs) with 95%
confi dence intervals (CIs). Demographic and household
poverty indicators were assessed for effect modifi cation
and confounding. Matched ORs adjusting for sex and the

2136 Emerging Infectious Diseases • www.cdc.gov/eid • Vol.
17, No. 11, November 2011
DISPATCHES CHOLERA IN HAITI
Author affi liations: Centers for Disease Control and
Prevention,
Atlanta, Georgia, USA (K.A. O’Connor, E. Cartwright, A.
Loharikar,
J. Routh, J. Gaines, T. Ayers, J.W. Tappero, T.H. Roels, W.R.
Archer, E. Mintz, R. Quick, B.E. Mahon); Ministry of Public
Health
and Population, Port-au-Prince, Haiti (M.-D.B. Fouché);
Centers for
Disease Control and Prevention, Port-au-Prince (R. Jean-Louis,
G.A. Dahourou); and Hôpital Albert Schweitzer, Deschapelles,
Haiti
(D. Johnson)
DOI: http://dx.doi.org/10.3201/eid1711.110810
presence of a mud fl oor in the household are presented
in the Table. As part of the public health response to the
outbreak, this investigation did not require human subjects
review. Informed consent was obtained.
We enrolled 49 case-patients and 98 controls; 16
(33%) case-patients and 53 (58%) controls were female.
The median age was 23 years for case-patients (range 6–63
years) and controls (range 5–75 years) (Table).
Few case-patients (15/49 [31%]) or controls (23/98
[23%]) had an improved drinking water source. The most
common water source was an unimproved well (30/49

[61%] of case-patients, 59/98 [60%] of controls). Similar
percentages of case-patients (33/42 [79%]) and controls
(69/93 [74%]) lacked safe water storage, and many case-
patients (28/46 [61%]) and controls (40/84 [48%]) practiced
open defecation.
Although comparable percentages of case-patients
(25/48 [52%]) and controls (48/95 [51%]) reported treating
their drinking water before the outbreak, case-patients were
signifi cantly less likely than controls to report treating their
drinking water during the outbreak (59% vs. 85%, mOR 0.2,
95% CI 0.1–0.7). Water treatment products were found in
homes of 31 (69%) of 45 case-patients and 73 (75%) of
98 controls. A lower, though not signifi cant, percentage
of case-patient households than control households (13/44
[30%] vs. 37/90 [41%]) had >0.1 mg/L of free chlorine in
stored water. Among 50 foods examined, only sugar cane
juice was associated with illness (9% vs.1%, mOR 9.1, CI
1.0–∞; data for other foods not shown).
Conclusions
This study, conducted early in the cholera epidemic
in Haiti in one of the fi rst populations to be affected,
demonstrated that treating drinking water was strongly
protective. This fi nding is not unexpected, because most
cholera outbreaks are spread through contaminated water, but
it provides compelling specifi c evidence that safe drinking
water is a critical need in Haiti. The disparity between the high
percentage of homes with water treatment products and the
lower percentage of homes with detectable chlorine in stored
drinking water suggested that the communication strategy
that accompanied product delivery needed modifi cation.
The low proportions of participants with an improved

water source, adequate water storage, and sanitary facilities
were typical of rural Haiti (4). Nevertheless, the increase
in reported frequency of treating drinking water during
the outbreak, particularly among controls, suggested that
MSPP’s cholera prevention message effectively reached
at least part of the population. This campaign may have
prevented the epidemic from causing even more illness
and death. The association with sugar cane juice also
emphasized that cholera can be transmitted by multiple
routes. In the study area, sugar cane juice is typically
produced by squeezing cane through a press; it is not
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 17, No.
11, November 2011 2137
CHOLERA IN HAITI Risk Factors Early in the 2010 Cholera
Epidemic
Table. Exposures of case-patients with cholera and matched
controls, Artibonite Department, Haiti, October–November
2010*
Variable
No. (%) case-patients
exposed, n = 49
No. (%) controls
exposed, n = 98 mOR (95% CI)
Participant completed primary school† 7 (23) 18 (31) 1.0 (0.2–
3.8)
Drinking water source
Improved water source 15 (31) 23 (23) 3.5 (0.6–40.8)
Well 30 (61) 59 (60) 0.3 (0.1–2.5)
Water storage
Lacked safe water storage 33 (79)‡ 69 (74)‡ 1.3 (0.5–4.0)

Bucket (unsafe storage) 31 (72)‡ 67 (70)‡ 1.1 (0.4–2.8)
Plastic bottle (safe storage) 7 (16)‡ 19 (20)‡ 0.6 (0.2–2.0)
Water treatment
Treating drinking water before the outbreak 25 (52)‡ 48 (51)‡
0.9 (0.4– 2.3)
Treating drinking water 3 d before illness onset (during
outbreak) 29 (59) 82 (85) 0.2 (0.1–0.7)
Water treatment product in home 31 (69)‡ 73 (75) 0.8 (0.3–2.4)
Drinking water test
Residual chlorine presence in home drinking water >0.1 mg/L
13 (30)‡ 37 (41)‡ 0.4 (0.1–1.3)
Residual chlorine presence in home drinking water >0.5 mg/L 8
(16)‡ 18 (18)‡ 0.4 (0.1–1.8)
Contact with river water 17 (35) 26 (27) 1.1 (0.4–3.1)
Sanitation and hygiene
Open defecation 28 (61) 40 (48)‡ 2.2 (0.7–7.8)
Handwashing with soap and lather 29 (59) 20 (41) 0.6 (0.3–1.5)
Household characteristics: electricity 8 (16) 29 (30) 0.6 (0.1–
2.3)
Food exposure: sugar cane juice 4 (9)‡ 1 (1)‡ 9.1§ (1.0–
*Exposures adjusted by sex and mud floor in home. Median age
of case-patients was 23 y (range 6–63 y); median age of
controls was 23 y (range 5–75
y). mOR, matched odds ratio; CI, confidence interval.
†Among those >15 y of age.
‡Denominators may be lower than the total number of
participants because of missing data.
§Median unbiased estimate.
typically made or served with water or ice, though we do
not know how the juice consumed by participants was
produced. After being contaminated with V. cholerae,
however, it provides a hospitable environment for bacterial
growth (5). These fi ndings highlight the central importance

of safe water in cholera control and the need to prevent
both foodborne and waterborne transmission.
The cholera epidemic should galvanize both
governmental and nongovernmental organizations to
address Haitians’ need for safe water and sanitation.
Experience in other cholera epidemics has shown that
the benefi ts will likely go beyond preventing the spread
of cholera; other serious public health problems, such as
typhoid fever and other enteric infections, have improved
substantially with effective measures to control cholera in
other settings (6).
Acknowledgments
We thank the many persons in Haiti who made this work
possible, including Ian Rawson, Carrie Weinrobe, and the staff
at
Hôpital Albert Schweitzer; the staff at Médecins Sans
Frontières
Belgium, Hôpital Charles Colimon; and our enumerators
(Frankie
Cledemon, Lucienne Orelius, Lynda Sejournee, Linda Ciceron,
and Stephanie Dorvil) and drivers (Olivier Felord and Emile
Saget) who assisted in data collection.
Lt O’Connor is an Epidemic Intelligence Service offi cer with
the Centers for Disease Control and Prevention in the Division
of Foodborne, Waterborne, and Environmental Diseases and
a lieutenant with the United States Public Health Service. Her
research interests include the epidemiology of enteric
pathogens.
References

1. Centers for Disease Control and Prevention. Update: chol-
era outbreak—Haiti, 2010. MMWR Morb Mortal Wkly Rep.
2010;59:1473–9.
2. Centers for Disease Control and Prevention. Update:
outbreak
of cholera—Haiti, 2010. MMWR Morb Mortal Wkly Rep.
2010;59:1586–90.
3. World Health Organization. Access to improved drinking-
water
sources and to improved sanitation (percentage). 2008 [cited
2011 Feb
18].
http://www.who.int/whosis/indicators/compendium/2008/2wst/
en/
4. World Health Organization/UNICEF Joint Monitoring
Programme
for Water Supply and Sanitation. 2010 [cited 2011 Mar 26].
http://
www.wssinfo.org/data-estimates/table/
5. Mahale DP, Khade RG, Vaidya VK. Microbiological
analysis of street
vended fruit juices from Mumbai city, India. Internet Journal of
Food
Safety. 2008;10:31–4 [cited 2011 Apr 4].
http://www.internetjfs.
org/articles/ijfsv10-5.pdf
6. Sepúlveda J, Valdespino JL, Garcia-Garcia L. Cholera in
Mexi-
co: the paradoxical benefi ts of the last pandemic. Int J Infect
Dis.
2006;10:4–13. doi:10.1016/j.ijid.2005.05.005

Address for correspondence: Katherine A. O’Connor, Centers
for Disease
Control and Prevention, 1600 Clifton Rd NE, Mailstop A38,
Atlanta, GA
30333, USA; email: [email protected]
DISPATCHES CHOLERA IN HAITI
Directions:Please complete all questions below and PLEASE
ADD 4 MORE new questions answer them for the public health
response to cholera in Haiti.
1. Describe norovirus (1-2 paragraphs) and explain why it
appears to garner less attention that other notable frequently
foodborne diseases.
2. What methods did O’Connor et al. employ to investigate the
cholera outbreak in Haiti?
3. Specifically, what methods did the team employ to treat
cholera patients and attempt to prevent additional incidence of
the disease?
4. What cultural and religious practices did the team need to be
aware of before beginning their investigation?
5. Describe one educational message (flyer, brochure, etc.) that
was used to help Haitian residents avoid consuming
contaminated water.
6. What was the source of the cholera outbreak? How was this
determined?

7. What makes it so difficult to have a stable, reliable health
care system in Haiti? Explain the political, cultural, and
economic issues involved.
Sprinkles, Anyone?
A Norovirus Outbreak in Lucas County, Ohio
Overview
Local Public Health Epidemiology
Outbreak Investigation
Timeline of Events
Descriptive Statistics
Lessons Learned
Closing Remarks
Epidemiology in Public Health
Disease Reporting
Monitors trends and outbreaks of disease symptoms and
confirmed diseases in Lucas County
Follow up investigations
Education to community-opportunity to reduce illness
Ohio Administrative Code
Reportable Diseases in Ohio
http://www.odh.ohio.gov/reportablediseases

http://www.odh.ohio.gov/reportablediseases
Outbreak
A sudden rise in the incidence of a disease (Merriam-Webster)
Occurrence of cases of disease in excess of what would
normally be expected in a defined community, geographical
area or season (World Health Organization)
Means the occurrence of cases of disease in numbers greater
than expected in a particular population or for a particular
period of time (ORC 3701-3)
For Class A diseases, “outbreak” usually means 1 case
For others, it is jurisdictionally-dependent
After Hours Disease Reporting
August 7, 2017 (Monday)
12:26 am—Received call through Engage Toledo
August 7, 2017
August 7, 2017

Epi Investigation
8:00 am– Updated epidemiologists of situation, began making
contact with hospital to identify patients seen in ER
Citizen calls started coming in regarding illness
Food Facility Investigation
8:00 am– Food Sanitarian began follow up with food facility
August 7, 2017
Epi Investigation
Family of 6
Family of 2
Noro +
August 7, 2017
Epi Investigation
Contacted ODH, received outbreak number
Numbers of self-reported ill individuals continued to climb
By close of business, reported 34 ill
Food Sanitarian obtained remaining doughnuts from facility
40 lb bag of doughnuts from July 26-August 4

20 lb bag of doughnuts from August 4-6
August 8, 2017 (Tuesday)
Epi Investigation
Continued to make calls and develop line listing– no apparent
pattern or trend
Daily update to Infection Preventionists
Daily update to Region
Shipped doughnut sample (20#) to ODH
Met with owners of restaurant, encouraged voluntary closure of
facility for deep cleaning
Became aware of doughnut wholesaling– major concern
Also made aware of customers potentially freezing doughnuts…
…and donut cakes
August 8, 2017
August 8, 2017

August 8, 2017
August 8, 2017
http://www.lucascountyhealth.com/community-
health/infectious-disease-epidemiology/
August 8, 2017
Wholesale Accounts
St V's (7 days a week)
UTMC Dana Center and Orthopedics (5 days a week)
St. Luke's (Mondays and Wednesdays)
Sunoco on Broadway (7 days a week)
Grounds for Thought (7 days a week)
Marathon on Dixie Highway (7 days a week)- 2 dozen
Hampton Inn on Reynolds (Mon, Wed, Fri, Sun)
Spartan Chemical (Wednesday)
Monclova Road Baptist Church (Sunday)
Calvary Assembly (Sunday)
First Presbyterian in Maumee (Sunday)
St. Joan of Arc (Sunday)
August 9, 2017 (Wednesday)

Epi Investigation
Continued to make calls and develop line listing
Daily update to Infection Preventionists
Daily update to Region
Concern for Delivery on 8/9
Revoked Facility License
Recommended professional cleaning service
August 9, 2017
August 10, 2017 (Thursday)
Epi Investigation
Continued to make calls and develop line listing– Surge Epis
and Food Sanitarians were called in due to volume of calls
(associated with press release and the media)
Daily update to Infection Preventionists + Region
Deep Cleaning of Facility using J & R Contracting Co in

Waterville, Ohio
Met with Contractors and went over plan for cleaning
HALT®
Sani-T 10®
August 10, 2017
August 10, 2017
August 10, 2017
Quick view of a form utilized by Epis (in Epi Info). This form
was also sent to other health jurisdictions who may have had
cases, such as Wood County
August 11, 2017 (Friday)
Epi Investigation
Continue interviews
Started receiving reports of secondary cases

Walked through facility after cleaning complete
Facility able to re-open
August 11, 2017
August 14, 2017 (Monday)
Epi Investigation
Received results from ODH
By close of business, reported 414 ill (primary and secondary)
Facility opened for business morning of 8/14
St. Luke’s used their UV Robot at the facility after facility
closed
August 14, 2017
August 14, 2017

August 14, 2017
Analysis primary cases
Impacted Counties:
Lucas County, Ohio
Wood County, Ohio
Henry County, Ohio
Sandusky County, Ohio
Fulton County, Ohio
Montgomery County, Ohio
Franklin County, Ohio
Ottawa County, Ohio
Monroe County, Michigan
Huron County, Michigan
Wayne County, Michigan
Impacted States
(County Not Available)
Indiana
Massachusetts
New York
Missouri
Kansas

Total primary cases ill: 381 reported
Primary case: All those whose illness was directly associated
with consuming a donut made at Mama C’s
EpiCurve Primary Cases N=376
42950 42951 42952 42953 42954 42955
42956 0 1 12 200 113 40 10
Onsate Date of Illness
Primary Case Count
Age Distribution of Primary Cases N=360
Infant (0-2) Preschool (3-5)Child (6-12) Adolescent (13-
17) Adult (18-64) Older Adult ( > 65) Unknown
2.3622047244094488E-2 6.5616797900262466E-2
0.14698162729658792 7.874015748031496E-2
0.56692913385826771 6.2992125984251968E-2
5.5118110236220472E-2

Sex Distribution of Primary Cases N=381
Male Female 0.45931758530183725 0.54068241469816269
Symptoms Reported of Primary Cases
N=379
Gas SOB Bloat Loss of Appetite Headache Nausea
Vomiting Diarrhea Ab Cramps Fever Dizzyness
Muscle Aches Lethargic/Fatigue Chills
2.6385224274406332E-3 2.6385224274406332E-3
1.0554089709762533E-2 5.2770448548812663E-3
0.12137203166226913 0.24538258575197888
0.85224274406332456 0.72559366754617416
0.22163588390501318 0.18205804749340371
1.3192612137203167E-2 0.13984168865435356
6.0686015831134567E-2 0.21372031662269128
Secondary Cases
Secondary Case: All individuals whose illness was acquired by
a primary case. Usually close contacts; family members,
friends, colleagues.
Secondary cases: 50 reported

EpiCurve of Secondary Cases N=50
42953 42954 42955 42956 42957 42958
42959 42960 42961 42962 42963 1 0
12 15 6 5 4 1 1 4 1
Illness Onset Date
Count
Secondary Cases
Age Distribution of Secondary Cases N=50
Infant (0-2) Preschool (3-5)Child (6-12) Adolescent (13-
17) Adult (18-64) Older Adult ( > 65) Unknown 0.04
0.02 0.12 0.1 0.62 0.08 0.02
Sex Distribution of Secondary Cases N=50
F M 26 24
Secondary Cases
Secondary Cases Symptoms Reported N=47
Bloat Headache Nausea Vomiting Diarrhea Ab Cramps
Fever Dizzyness Muscle Aches Lethargic/Fatigue
Chills 2.1276595744680851E-2 0.14893617021276595

0.31914893617021278 0.68085106382978722
0.74468085106382975 0.42553191489361702
0.2978723404255319 2.1276595744680851E-2
0.1702127659574468 8.5106382978723402E-2
8.5106382978723402E-2
Education, Education, Education!
Education to prevent secondary cases
Education to food facility
It also was a learning experience for TLCHD
Cholera and Other Waterborne Diseases

1
Cholera
Cholera is transmitted by water or food that has been
contaminated with infective feces.
The risk for transmission can be greatly reduced by disinfecting
drinking water, separating human sewage from water supplies,
and preventing food contamination.
2
Cholera
Untreated cholera is fatal in ≈25% of cases, but with aggressive
volume and electrolyte replacement, the number of persons who
die of cholera is limited to <1%.
3
4
5
Cholera
Agent: Vibrio cholerae
Distributed worldwide, particularly in tropics
Symptoms: 1-2 day incubation, exotoxin of V. cholerae causes
disease

Severe cases require rapid and extensive rehydration
Estimated 1,000,000 cases per year
Watery diarrhea and dehydration
6
6
Cholera is an acute bacterial enteric disease characterized in its
severe form by sudden onset, profuse watery stools, nausea, and
vomiting early in the course of illness. In untreated cases, rapid
dehydration, acidosis, circulatory collapse, and renal failure can
occur. Diagnosis is confirmed by isolating Vibrio cholerae of
the serogroup O1 or O139 from feces. Numerous pandemics of
cholera occurred, primarily in the 1800s in India, Russia,
Europe, Mecca, Asia, and Africa. For the first half of the 20th
century, much of cholera was confined to Asia, except for a
severe epidemic in Egypt in 1947. During the second half of
the 20th century, three major observations have occurred
regarding cholera: 1. the global spread of the seventh pandemic
of cholera caused by V. cholerae O1 El Tor, 2. the recognition
that environmental reservoirs of cholera exist and include one
along the Gulf of Mexico coast of the U.S., and 3. the
appearance for the first time of large explosive epidemics of
cholera gravis caused by other serogroups (O139).
Morris gives an excellent account of the four Cholera epidemics
which spread across Europe in the 19th century. Originally
confined to the Bengal region of India (and thus known as
Asiatic cholera) where it periodically ravaged the region; it
somehow, in 1817, underwent a change. Morris attributes this to
two factors - more overseas trade which encouraged its spread
across to Persia (Iran) and thence on to Europe and the British
Army's regular rotation of troops which allowed it to escape out
of its confined region. The disease was thus familiar to Army
doctors and to troops (it is estimated that it killed some 3000 of
Hastings' 10,000 strong army). By 1823 it had reached Russian
Astrakhan and for a period stopped. In 1826 it re-occurred at a

great religious pilgrimage at Hurdwar and was carried back by
pilgrims along trade routes. Unfortunately it reached Russian
Nijni-Novogorod in time to infect the autumn trade fair - again
trade routes saw it spread quickly to Moscow in 1830 and from
then on it was merely a matter of time before it spread to all of
Europe. In September 1831 it had reached Hamburg which had
many trade links with Britain - the first British death occurred
in October at Sunderland.
The arrival of the Cholera was long heralded in the Manx Press
which from 1831 tracked its progress across Europe; on 25th
May 1832 it reported Cholera in Liverpool and the first case in
Douglas (Thomas Woods) was reported 17 July 1832 (see also
account by George Head). This outbreak lasted until September
1832, a second outbreak occurred in August-September 1833.
Some of the social attitudes have already been mentioned above.
Cholera
Treatment: Oral rehydration
Transmission: Drinking of contaminated water, consumption of
infected fish, shellfish
Dormancy in aquatic environments, maintenance on zooplankton
Prevention and Control: HYGIENE! Sewage treatment, cook
foods properly.
7
7
Humans are the reservoir for cholera and cholera is transmitted
through ingestion of food or water contaminated directly or
indirectly with feces or vomitus of infected persons. The main
serogroups of cholera (O1 and O139 can persist in water for
long periods. When traveling to countries with suspect water

supplies, it is advised not to consume beverages produced in
those countries, as the water may very well be contaminated.
Vegetables and fruit may also be suspect as they could have
been grown or treated with this water during or after the
planting and growing process. The incubation period of cholera
is usually 2-3 days long and as long as stools are positive for
cholera, it is communicable.
The key to preventing cholera is to ensure a safe water supply.
Chlorination of public water is a must, even if the source water
appears to be uncontaminated. Careful preparation of food and
beverages and after cooking or boiling, protect against
contamination by flies and unsanitary handling, leftover foods
should be thoroughly reheated before ingestion. Persons with
diarrhea should not prepare food or haul water for others.
Without treatment Cholera kills around 40-60% of those
infected. The disease causes constant vomiting and purging of
the bowels - often as much as several pints in a few minutes.
Descriptions abound of sodden bedclothes (highly infectious)
and floors awash - such dehydration causes cramps, the body
shrivels so much so that the sufferer is said to look like a
monkey and the blood becomes too thick to be easily circulated
thus turning the extremities black or blue. However this acute
stage only lasts some 24 hours, at the end of which the victim is
either dead or on their way to a slow recovery. As mentioned in
the introduction, infection is by polluted water in which the
excreta of an infected person enter into drinking water. The
microbe is however killed by heat or by acid, some people can
drink polluted water and avoid infection due to their stomach
acid. Nurses would use vinegar to remove the smell of vomit
from their hands, by doing so they would also kill the microbe.
8

Giardiasis
Protozoan infection often of upper small intestine, associated
with chronic diarrhea, steatorrhea, abdominal cramps, bloating,
fatigue, and weight loss.
Infectious agent: Giardia lamblia
Occurrence: Worldwide, mostly children
9
9
Diagnosis is traditionally made by identification of cysts or
trophozoites in feces or of trophozoites in duodenal fluid or in
mucosa obtained by small intestine biopsy. Children are
infected more frequently than adults. Prevalence is higher in
areas of poor sanitation and in institutions with children not
toilet trained, including day care centers. Endemic infection in
the U.S. UK, and Mexico most commonly occurs in July-
October among children less than 3 years of age and adults 25-
39 years old. It is associated with drinking water from
unfiltered surface water sources or shallow wells, swimming in
bodies of freshwater and having a young family member in day
care.
Person to person transmission occurs by hand to mouth transfer
of cysts from the feces of an infected individual, especially in
institutions and day care centers, this is probably the mode of
spread. Anal intercourse also facilitates transmission. The
agent is communicable during the entire period of infection,
which could be months. The way to prevent giardiasis is to
educate families, those in day care centers, etc., in proper
hygiene and handwashing. Filter public water and sanitary

disposal of feces is required.
From Giardia: A Common Waterborne Disease
Surface water is especially vulnerable to Giardia contamination,
and this explains why it is often called "beaver fever" or
backpacker disease. "Many years ago, what we now know as
giaridiasis was called beaver fever, because people who drank
creek water downstream from a beaver dam often got sick,"
Hairston says. "Likewise, hikers and nature lovers who sample
what they believe is "pure" water from a stream often end up
sick because the water contains Gardia oocysts from grazing
cattle or game animals."
Giardiasis
Reservoir: Humans
Mode of Transmission: person to person, fecal-oral from
contaminated water
Incubation period: 3-25 days
10
10
Diagnosis is traditionally made by identification of cysts or
trophozoites in feces or of trophozoites in duodenal fluid or in
mucosa obtained by small intestine biopsy. Children are
infected more frequently than adults. Prevalence is higher in
areas of poor sanitation and in institutions with children not
toilet trained, including day care centers. Endemic infection in
the U.S. UK, and Mexico most commonly occurs in July-
October among children less than 3 years of age and adults 25-
39 years old. It is associated with drinking water from
unfiltered surface water sources or shallow wells, swimming in
bodies of freshwater and having a young family member in day

care.
Person to person transmission occurs by hand to mouth transfer
of cysts from the feces of an infected individual, especially in
institutions and day care centers, this is probably the mode of
spread. Anal intercourse also facilitates transmission. The
agent is communicable during the entire period of infection,
which could be months. The way to prevent giardiasis is to
educate families, those in day care centers, etc., in proper
hygiene and handwashing. Filter public water and sanitary
disposal of feces is required.
From Giardia: A Common Waterborne Disease
Surface water is especially vulnerable to Giardia contamination,
and this explains why it is often called "beaver fever" or
backpacker disease. "Many years ago, what we now know as
giaridiasis was called beaver fever, because people who drank
creek water downstream from a beaver dam often got sick,"
Hairston says. "Likewise, hikers and nature lovers who sample
what they believe is "pure" water from a stream often end up
sick because the water contains Gardia oocysts from grazing
cattle or game animals."
11
Leptospirosis
Zoonotic bacterial disease with features of fever, headache,
chills, myalgia, and conjunctival suffusion
Infectious agent: leptospires
Occurrence: Worldwide
Reservoir: Wild and domestic animals
Mode of Transmission: Contact of the skin or mucous
membranes with contaminated water

Incubation Period: usually 10 days
12
12
Outbreaks of leptospirosis are usually caused by exposure to
water contaminated with the urine of infected animals. Many
different kinds of animals carry the bacterium; they may
become sick but sometimes have no symptoms. Leptospira
organisms have been found in cattle, pigs, horses, dogs, rodents,
and wild animals. Humans become infected through contact
with water, food, or soil containing urine from these infected
animals. This may happen by swallowing contaminated food or
water or through skin contact, especially with mucosal surfaces,
such as the eyes or nose, or with broken skin. The disease is not
known to be spread from person to person. Leptospirosis occurs
worldwide but is most common in temperate or tropical
climates. It is an occupational hazard for many people who
work outdoors or with animals, for example, farmers, sewer
workers, veterinarians, fish workers, dairy farmers, or military
personnel. It is a recreational hazard for campers or those who
participate in outdoor sports in contaminated areas and has been
associated with swimming, wading, and whitewater rafting in
contaminated lakes and rivers. The incidence is also increasing
among urban children.
Other manifestations that may be present are diphasic fever,
meningitis, rash, hemolytic anemia, hemorrhage into skin and
mucous membranes, hepatorenal failure, jaundice. Cases are
often misdiagnosed with meningitis, encephalitis, or influenza.
Clinical illness lasts from a few days to 3 weeks or longer.
Generally, there are two phases in the illness; the leptospiremic
or febrile stage, followed by the convalescent or immune phase.

The disease is an occupational hazard for rice and sugarcane
fieldworkers, farmers, sewer workers, miners, veterinarians,
animal husbnadrymen, dairymen, fish workers, and military
troops. Outbreaks occur among those exposed to fresh river,
stream, canal, and lake water contaminated by urine of domestic
and wild animals, and to urine and tissues of infected animals.
The disease is a recreational hazard to bathers, campers, and
sportsmen in infected areas. Notable reservoirs are rats, swine,
cattle, dogs, and raccoons. Direct transmission from person to
person is rare. Leptospires may be excreted in the urine.
The public must be educated on the modes of transmission and
to avoid swimming or wading in potentially contaminated
waters. Those in occupations requiring contact with this water
need to wear protections such as boots, gloves, aprons, etc.
Leptospirosis
Risk factors include:
Occupational exposure -- farmers, ranchers, slaughterhouse
workers, trappers, veterinarians, loggers, sewer workers, rice
field workers, and military personnel
Recreational activities -- fresh water swimming, canoeing,
kayaking, and trail biking in warm areas
Household exposure -- pet dogs, domesticated livestock,
rainwater catchment systems, and infected rodents
Leptospirosis is rare in the continental United States. Hawaii
has the highest number of cases in the United States.
13
Schistosomiasis
Blood fluke infection (trematode) with worms living within
mesenteric or vesical veins of the host over a life span of many
years

Results of chronic infection include liver fibrosis, portal
hypertension, urinary manifestations including bladder cancer
Infectious Agent: Schistosoma mansomi
Occurrence: Africa, South America
Reservoir: Humans
14
14
Schistosomiasis, also known as bilharzia (bill-HAR-zi-a), is a
disease caused by parasitic worms. Infection with Schistosoma
mansoni, S. haematobium, and S. japonicum causes illness in
humans. Although schistosomiasis is not found in the United
States, 200 million people are infected worldwide.
People, dogs, cats, pigs, cattle, water buffalo, horses, and wild
rodents are potential hosts of some of the other species
(japonicum and heamatobium). Definitive diagnosis of
schistosomiasis depends on demonstration of eggs in the stool
microscopically by direct smear or on a Kato thick smear.
Infection is acquired from water containing free swimming
larval forms (cercariae) that have developed in snails. The eggs
hatch in water and the liberated larvae penetrate into suitable
freshwater snail hosts. After several weeks, the cercariae
emerge from the snail and penetrate human skin, usually while
the person is working, swimming, or wading in water; they enter
the bloodstream and are carried to blood vessels of the lungs,
migrate to the liver, develop to maturity and then migrate to
veins of the abdominal cavity.
The incubation period is about 2-6 weeks. It is not
communicable from person to person. The way to prevent
schistosomiasis is to improve irrigation and agriculture practice.
Dispose of feces and urine so that viable eggs will not reach
fresh bodies of water that have snail hosts. Avoid swimming or

working in contaminated water. Provide drinking and bathing
water from uncontaminated source.
Naegleria
15
Naegleria fowleri
Microscopic, free-living amoeba that can cause rare, but severe
infections of the brain
Commonly found in the environment in water and soil
Infects people by entering the body through the nose, often from
swimming and diving in freshwater lakes and rivers
16
Naegleria fowleri is a microscopic, free-living amoeba (single-
celled living organism) that can cause rare, but severe
infections of the brain. The free-living ameba is commonly
found in the environment in water and soil. Naegleria fowleri
infects people by entering the body through the nose. This
typically occurs when people go swimming or diving in warm
freshwater places, like lakes and rivers. Once the ameba enters
the brain it causes a severe and usually fatal infection called
primary amebic meningoencephalitis (PAM). The risk for
infection from Naegleria fowleri might be reduced by measures
that minimize opportunities for water to enter the nose when
using warm freshwater lakes or rivers.
16
Naegleria fowleri
Once the amoeba enters the brain it causes a severe and usually

fatal infection called primary amebic meningoencephalitis
(PAM)
17
18
Naegleria fowleri has three stages, cysts , trophozoites , and
flagellated forms , in its life cycle. The trophozoites replicate
by promitosis (nuclear membrane remains intact) . N. fowleri is
found in fresh water, soil, thermal discharges of power plants,
heated swimming pools, hydrotherapy and medicinal pools,
aquariums, and sewage. Trophozoites can turn into temporary
non-feeding flagellated forms which usually revert back to the
trophozoite stage. Trophozoites infect humans or animals by
penetrating the nasal mucosa and migrating to the brain via the
olfactory nerves causing primary amebic meningoencephalitis
(PAM). N. fowleri trophozoites are found in cerebrospinal fluid
(CSF) and tissue, while flagellated forms are occasionally found
in CSF. Cysts are not seen in brain tissue.
18
Where is Naegleria fowleri found?
Worldwide, primarily Southern U.S. in:
Bodies of warm freshwater, lakes and rivers
Geothermal (naturally hot) water, hot springs
Geothermal (naturally hot) drinking water sources
Warm water discharge from industrial plants
Swimming pools that are poorly maintained, minimally-
chlorinated, and/or un-chlorinated

Soil
19
found around the world. In the United States, the majority of
infections have been caused by Naegleria fowleri from
freshwater located in southern-tier states. The ameba is most
commonly found in:
Bodies of warm freshwater, such as lakes and rivers
Geothermal (naturally hot) water, such as hot springs
Geothermal (naturally hot) drinking water sources
Warm water discharge from industrial plants
Swimming pools that are poorly maintained, minimally-
chlorinated, and/or un-chlorinated
Soil
Naegleria fowleri is not found in salt water.
19
Number of Case-reports of Primary Amebic
Meningoencephalitis Caused by Naegleria fowleri (N=143) by
State of Exposure*— United States, 1962–2017
20
https://www.cdc.gov/parasites/naegleria/state-map.html
Most cases in Texas and SE, SW United States.
When do infections occur?
Infections usually occur when it is hot for prolonged periods of
time, which causes higher water temperatures and lower water
levels. Infections can increase during heat wave years.
21

Statistics – United States
Naegleria fowleri infections are very rare. In the 10 years from
2000 to 2009, 30 infections were reported in the U.S.
Of those cases, 28 people were infected by contaminated
recreational water and 2 people were infected by water from a
geothermal (naturally hot) water supply.
Infections typically occur in July, August, and September.
22
22
Symptoms
Naegleria fowleri can cause the disease primary amoebic
meningoencephalitis (PAM), a brain infection that leads to the
destruction of brain tissue.
In its early stages, symptoms of PAM may be similar to
symptoms of bacterial meningitis.
23
Symptoms
Initial symptoms include headache, fever, nausea, vomiting, and
stiff neck.
Later symptoms include confusion, lack of attention to people
and surroundings, loss of balance, seizures, and hallucinations.

After the start of symptoms, the disease progresses rapidly and
usually causes death within 1 to 12 days.
24
Treatment?
Several drugs are effective against Naegleria fowleri in the
laboratory. However, their effectiveness is unclear since almost
all infections have been fatal, even when people were treated.
25
How common is Naegleria fowleri in the environment?
Naegleria fowleri is commonly found in lakes in southern-tier
states during the summer.
This means that recreational water users should be aware that
there will always be a low level risk of infection when entering
these waters.
26
Is it possible to test for Naegleria fowleri in the water?
No. It can take weeks to identify the ameba, but new detection
tests are under development. Previous water testing has shown
that Naegleria fowleri is very common in freshwater venues.
Therefore, recreational water users should assume that there is a
low level of risk when entering all warm freshwater,
particularly in southern-tier states.
27

What is the risk of infection?
The risk of Naegleria fowleri infection is very low.
There have been 30 reported infections in the U.S. in the 10
years from 2000 to 2009, despite millions of recreational water
exposures each year.
By comparison, in the ten years from 1996 to 2005, there were
over 36,000 drowning deaths in the U.S.
You cannot be infected with Naegleria fowleri by drinking
contaminated water and the amoeba is not found in salt water.
28
What is the risk of infection?
It is likely that a low risk of Naegleria fowleri infection will
always exist with recreational use of warm freshwater lakes,
rivers, and hot springs.
The low number of infections makes it difficult to know why a
few people have been infected compared to the millions of other
people using the same or similar waters across the U.S.
29
The only certain way to prevent a Naegleria fowleri infection is
to refrain from water-related activities in warm, untreated, or
poorly-treated water.
29
June 19, 2016 – Ohio teen dies
Exposed to water (suspected source) at U.S. National
Whitewater Center in Charlotte, NC

http://www.cnn.com/2016/06/22/health/brain-eating-amoeba-
killed-ohio-teenager/
30
Rare but Fatal
Kline noted that Naegleria fowleri infections are rare. The
CDC reported 37 infections in the 10 years from 2006 to 2015.
But the fatality rate of the infection is as high as 97%.
"Only 3 out of the 138 known infected individuals in the United
States from 1962 to 2015 have survived," the CDC said.
31
Prevention Methods
Avoid water-related activities in warm freshwater during
periods of high water temperature and low water levels.
Hold the nose shut or use nose clips when taking part in water-
related activities in bodies of warm freshwater.
Avoid digging in or stirring up the sediment while taking part in
water-related activities in shallow, warm freshwater areas.
32
Waterborne Disease and Outbreak Surveillance System
National Outbreak Reporting System (NORS)
http://www.cdc.gov/healthywater/statistics/wbdoss/nors/index.h
tml
Outbreak Response Guides

http://www.cdc.gov/healthywater/emergency/toolkit/index.html
#guides
Cryptosporidium and Norovirus guides
33
NORS launched in 2009 following a four year commitment by
CDC to the planning, development, and launch phases of the
project. CDC developed NORS for waterborne disease outbreak
reporting in collaboration with the Council for State and
Territorial Epidemiologists (CSTE) and the Environmental
Protection Agency (EPA) to improve the quality, quantity, and
availability of data submitted to the Waterborne Disease and
Outbreak Reporting System (WBDOSS).
The launch of NORS represents an important shift in national
waterborne disease outbreak reporting—a transition from paper-
based reporting to electronic reporting of outbreak data.
33
Cryptosporidiosis
Caused by a protozoa, Cryptosporidium hominis or
Cryptosporidium parvum.
Incubation Period: 1-12 days. Average of 7 days.
Outbreaks often reported in day care centers.
34

Cryptosporidiosis
The most common symptom of cryptosporidiosis is watery
diarrhea. Other symptoms include
Dehydration
Weight loss
Stomach cramps or pain
Fever
Nausea
Vomiting
35
Cryptosporidiosis
Crypto has become recognized as one of the most common
causes of waterborne disease (recreational water and drinking
water) in humans in the United States.
The parasite is found in every region of the United States and
throughout the world.
36
Cryptosporidiosis
Shedding of Crypto in the stool begins when the symptoms
begin and can last for weeks after the symptoms (e.g., diarrhea)
stop.
You can become infected after accidentally swallowing the
parasite. Cryptosporidium may be found in soil, food, water, or
surfaces that have been contaminated with the feces from
infected humans or animals.
37
Spread of Cryptosporidiosis

By putting something in your mouth or accidentally swallowing
something that has come into contact with stool of an infected
person or animal
Swallowing contaminated recreational water
Drinking contaminated beverages
Eating uncooked, contaminated food
Touching your mouth with contaminated hands
Exposure to feces via sexual contact
38
Symptoms
Stomach cramps or pain
Dehydration
Nausea
Vomiting
Fever
Weight loss
Small intestine typically affected
39
Symptoms
Incubation period is 2-10 days, average is 7 days.
In persons with healthy immune systems, symptoms usually last
about 1 to 2 weeks. The symptoms may go in cycles in which
you may seem to get better for a few days, then feel worse again

before the illness ends.
40
At-risk Populations: Swimmers
Cryptosporidium now causes over half of the reported
waterborne disease outbreaks associated with swimming in
chlorinated public swimming pools.
Cryptosporidium’s chlorine resistance and documented
excretion for weeks after resolution of symptoms has led CDC
and The American Academy of Pediatrics to recommend that all
persons refrain from swimming until 2 weeks after resolution of
symptoms.
41
Diagnosis and Treatment
Diagnosed by stool sample and subsequent analysis
Nitazoxanide has been FDA-approved for treatment of diarrhea
caused by Cryptosporidium in people with healthy immune
systems and is available by prescription.
42
Diarrhea can be managed by drinking plenty of fluids to prevent
dehydration. Young children and pregnant women may be more
susceptible to dehydration. Rapid loss of fluids from diarrhea
may be especially life threatening to babies. Therefore, parents
should talk to their health care provider about fluid replacement
therapy options for infants. Anti-diarrheal medicine may help

slow down diarrhea, but a health care provider should be
consulted before such medicine is taken.
People who are in poor health or who have weakened immune
systems are at higher risk for more severe and more prolonged
illness. The effectiveness of nitazoxanide in immunosuppressed
individuals is unclear. HIV-positive individuals who suspect
they have Crypto should contact their health care provider. For
persons with AIDS, anti-retroviral therapy that improves
immune status will also decrease or eliminate symptoms of
Crypto. However, even if symptoms disappear,
cryptosporidiosis is often not curable and the symptoms may
return if the immune status worsens.
42
Treatment
In 2004, the FDA licensed nitazoxanide (Alinia) for all persons
≥ 1 year of age.
Adult dosage (immune competent)
500 mg BID x 3 days
Pediatric dosage (immune competent)
1-3 years: 100 mg BID x 3 days
4-11 years: 200 mg BID x 3 days
43
Treatment
Nitazoxanide oral suspension (100 mg/5ml; patients ≥ 1 year of
age) and Nitazoxanide tablets (500 mg; patients ≥ 12 years of
age) are indicated for the treatment of diarrhea caused by
Cryptosporidium.
Clinical cure (resolution of diarrhea) rates range from 72-88%

It may take up to 5 days for diarrhea to resolve in
approximately 80% of patients
44
45
Cryptosporidium Outbreak in Childcare Setting
Cryptosporidium is resistant to chlorine disinfection so it is
tougher to kill than most disease-causing germs.
The usual disinfectants, including most commonly used bleach
solutions, have little effect on the parasite.
An application of hydrogen peroxide works best.
46
Cryptosporidium Outbreak in Childcare Setting
Educate staff and parents
Inform all staff about the ongoing outbreak, the symptoms of
Crypto, how infection is spread, control measures to be
followed, outbreak control policies, and needed changes in
hygiene and cleanliness.
Notify parents of children who have been in direct contact with
a child or an adult caregiver with diarrhea. Parents should

contact the child's healthcare provider if their child develops
diarrhea.
47
An epidemic of cholera infections was documented in
Haitifor the first time in more than 100 years during
October
2010. Cases have continued to occur, raising
the question
of whether the microorganism has established environmen-
tal reservoirs in Haiti. We monitored 14
environmental sites
near the towns of Gressier and Leogane during
April 2012–
March 2013. Toxigenic Vibrio cholerae O1 El
Tor biotype
strains were isolated from 3 (1.7%) of 179 water
samples;
nontoxigenic O1 V. cholerae was isolated from an addition-
al 3 samples. All samples containing V. cholerae
O1 also
contained non-O1 V. cholerae. V. cholerae O1 was isolated
only when water temperatures were ≥31°C. Our
data sub-
stantiate the presence of toxigenic V. cholerae O1 in
the
aquatic environment in Haiti. These isolations
may reflect

establishment of long-term environmental reservoirs in
Haiti, which may complicate eradication of cholera from this
coastal country.
Epidemic cholera was identified during October 2010 in Haiti;
initial cases were concentrated along the Ar-
tibonite River (1,2). The clonal nature of isolates during
this initial period of the epidemic has been described (3–6).
Because cholera had not been reported in Haiti for at least
100 years, there is a high likelihood that the responsible
toxigenic Vibrio cholerae strain was introduced into Haiti,
possibly through Nepalese peacekeeping troops garrisoned
at a camp along the Artibonite River (4,7). In the months
after October 2010, cholera spread quickly through the rest
of Haiti: 604,634 cases and 7,436 deaths were reported in
the first year of the epidemic (1). In the intervening years,
cases and epidemics have been reported, and it has been
suggested that onset of the rainy season serves as a trigger
for disease occurrences (2,8).
V. cholerae is well recognized as an autochthonous
aquatic microorganism species with the ability to survive
indefinitely in aquatic reservoirs and is possibly in a “per-
sister” phenotype (9). V. cholerae strains can also persist
in aquatic reservoirs as a rugose variant that promotes
formation of a biofilm that confers resistance to chlorine
and to oxidative and osmotic stresses (10–13) and also
persists in a viable but nonculturable form (14). Work
by our group and others suggests that cholera epidemics
among humans are preceded by an environmental bloom
of the microorganism and subsequent spillover into hu-
man populations (15–17). In our studies in Peru (16), wa-
ter temperature was found to be the primary trigger for
these environmental blooms and could be correlated with
subsequent increases in environmental counts and occur-

rence of human illness.
To understand patterns of ongoing cholera transmis-
sion and seasonality of cholera in Haiti, and to assess the
likelihood of future epidemics, it is essential to know
whether environmental reservoirs of toxigenic V. chol-
erae O1 have been established, where these reservoirs
are located, and what factors affect the occurrence and
growth of the microorganism in the environment. We re-
port the results of an initial year of monitoring of envi-
ronmental sites in the Ouest Department of Haiti, near the
towns of Leogane and Gressier, where the University of
Florida (Gainesville, FL, USA) has established a research
laboratory and field area.
Monitoring Water Sources for
Environmental Reservoirs of
Toxigenic Vibrio cholerae O1, Haiti
Meer T. Alam, Thomas A. Weppelmann, Chad D. Weber, Judith
A. Johnson, Mohammad H. Rashid,
Catherine S. Birch, Babette A. Brumback, Valery E. Madsen
Beau de Rochars,
J. Glenn Morris, Jr., and Afsar Ali
RESEARCH
356 EmergingInfectious Diseases • www.cdc.gov/eid •
Vol. 20, No. 3, March 2014
Author affiliations: University of Florida College
of Public Health
and Health Professions, Gainesville, Florida, USA
(M.T. Alam,
T.A. Weppelmann, V.E. Madsen Beau de Rochars, A.

Ali); University
of Florida Emerging Pathogens Institute, Gainesville
(M.T. Alam,
T.A. Weppelmann, C.D. Weber, J.A. Johnson, M.H.
Rashid,
C.S. Birch, B.A. Brumback, V.E. Madsen
Beau de Rochars,
J.G. Morris, Jr., A. Ali); and University of Florida
College of Medicine,
Gainesville (M.H. Rashid, V.E. Madsen Beau de
Rochars, A. Ali)
EmergingInfectious Diseases • www.cdc.gov/eid •
Vol. 20, No. 3, March 2014 357
Methods
Environmental Sampling Sites
Fifteen fixed environmental sampling sites were se-
lected near Gressier and Leogane (Figures 1,2). Sites were
selected along transects of 3 rivers in the area and at 1 inde-
pendent estuarine site: the Momance River (4 up-river sites
and 1 estuarine site at the mouth of the river), the Gressier
River (4 up-river sites and 1 estuarine site at the mouth of
the river), the Tapion River (4 river sites), and an indepen-
dent estuarine site at Four-a-chaux, which is a historic ruin
and tourist attraction. All sites were >0.5 miles apart, with
the exception of the Christianville Bridge and Spring sites,

which were 0.25 miles apart. Topography of this area is
typical for Haiti: rivers originated in the mountains (peaks
in the region are >8,000 feet) and flowed into a broad flood
plain where Gressier and Leogane were located. Up-riv-
er sites on the Momance and Gressier Rivers were in the
Figure 1. Locations of environmental
sampling sites near the towns of
Gressier and Leogane in Haiti.
Samples were collected during April
2012–March 2013. A) Number of Vibrio
cholerae O1 isolates obtained from
sampling sites. B) Number of non-O1/
non-O139 V. cholerae isolates obtained
from sampling sites. The number of V.
cholerae isolates obtained from each
sampling site is indicated by distinct
color coding.
RESEARCH
mountains, where human populations are limited. Water
samples were collected once a month from each site during
April 2012–March 2013. A total of 179 samples were col-
lected for culture for V. cholerae; 176 samples were avail-
able for measurement of water quality parameters.
Isolation and Identification of V. cholerae
from Environmental Sites
For the isolation of V. cholerae, 500 ml of water was
collected in a sterile 500-mL Nalgene (http://nalgene.com/)
bottle from each fixed site; the samples were transported at
ambient temperature to the University of Florida labora-

tory at Gressier and processed for detection of V. cholerae
within 3 hours of collection.
In addition to the conventional sample enrichment
technique (18), we used alkaline peptone water (APW) to
enrich water samples. A 1.5-mL water sample was enriched
with 1.5 mL of 2× APW in 3 tubes: 1 tube was incubated at
37°C for 6–8 hours (18), another tube was incubated over-
night at 37°C, and the third tube was incubated at 40°C for
6–8 hours. Subsequently, a loopful of culture from each
tube was streaked onto thiosulfate citrate bile salts sucrose
agar (Becton-Dickinson, Franklin Lakes, NJ, USA), and the
plates were incubated overnight at 37°C. From each plate,
6–8 yellow colonies exhibiting diverse morphology were
transferred to L-agar; these plates were incubated overnight
at 37°C. Each colony was examined by using the oxidase
test; oxidase-positive colonies were tested by using V. chol-
erae O1–specific polyvalent antiserum and O139-specific
antiserum (DENKA SEIKEN Co., Ltd, Tokyo, Japan). The
isolates were further examined by using colony PCR for the
presence of ompW and toxR genes specific for V. cholerae
spp. as described (9).
Screening of Aquatic Animals and Plants
To determine whether they serve as reservoirs for V.
cholerae O1, we collected aquatic animals typically eat-
en by humans, including shrimp, fish, crab, crayfish, and
aquatic plants (n = 144) weekly during February 5–22,
2013. The samples were collected from 14 environmental
sites. Each sample was placed into a sterile plastic seam–
locking bag and transported to the laboratory. One gram of
the sample was mixed with 100 mL of saline and then ho-
mogenized in a sterile blender; 1.5 ml of the resultant mix-
ture was enriched in 2× APW and processed as described.

Genetic Characterization of V. cholerae O1 Strains
To further characterize the environmental V. cholerae
O1 serogroup Ogawa biotype El Tor strains, we subjected
all V. cholerae O1 isolates from water and seafood to PCR
analysis for key virulence genes, including ctxA, ctxB-CL,
(MAMA-CL), ctxB-ET (MAMA-ET), rstR-ET, rstR-CL, rstC-
ET,
rstC-CL, tcpA-CL, and tcpA-ET, as described (19,20). The
chro-
mosomal DNA was extracted from each strain by using a
GenElute Bacterial Genomic DNA kit (Sigma-Aldrich, St.
Louis, MO, USA), and the DNA was used for PCR tem-
plates; the PCR conditions were as described (3).
Aerobic Plate Counts
To determine total aerobic bacterial counts in water
samples, we plated undiluted, 10- and 100-fold dilutions
of water onto L-agar and incubated overnight at 37°C.
Vol. 20, No. 3, March 2014
Figure 2. Mean combined water
temperature for all sites monitored
in the Ouest Department of Haiti,
near the towns of Leogane and
Gressier, and percentage of
environmental sites positive for
Vibrio cholerae O1 or non-O1/
non-O139, by month.

The countable plates (100–300 colonies) were used to de-
termine the total (CFU/mL) culturable bacteria present in
the water samples.
Water Parameters, Rainfall, and Human Case Counts
When collecting water samples, we measured physi-
cal parameters, including pH, water temperature, dissolved
oxygen, total dissolved solids, salinity, and conductivity
in the field sites by using a HACH portable meter (HACH
Company, Loveland, CO, USA) and designated electrodes
following the manufacturer’s recommendations. Rainfall
estimates were based on National Aeronautics and Space
Administration data for the study region bounded by the
rectangle (18.2°–18.6°N, 17.1°–17.8°W) by using the av-
erage daily rainfall measurement tool, Tropical Rainfall
Measuring Mission 3B42_daily (21). Estimates of average
precipitation (mm/day) with a spatial resolution of 0.25 ×
0.25 degrees were aggregated to obtain weekly accumulat-
ed rainfall measurements during the study period. Cholera
incidence data were obtained from daily reports by Ouest
Department (excluding Port-au-Prince) to the Haitian Min-
istry of Public Health and Population and aggregated to total
cases per week during April 20, 2012–March 27, 2013 (22).
Data Analysis
We examined the effects of water quality factors on
the presence of toxigenic and nontoxigenic V. cholerae by
conditional logistic regression after stratification for the
site. Stratification excluded sites that had all-positive or
all-negative outcomes; of the remaining sites, regression
analysis showed O1 V. cholerae in 47 observations from
4 sites and non-O1/non-O139 V. cholerae in 154 observa-

tions from13 sites. As shown in Figure 1, we performed
cartography by using ArcGIS version 10 (ESRI, Redlands,
CA, USA).
Results
V. cholerae O1 serogroup Ogawa biotype El Tor
was isolated from 6 (3.4%) of the 179 water samples and
1 (0.7%) of the 144 aquatic animal and plant samples by
using modified APW enrichment techniques. Of those 7
environmental isolates, 3 (43%) were confirmed as ctx-
positve toxigenic V. cholerae O1 strains, and 4 (57%) were
confirmed as ctx-negative V. cholerae O1 strains by using
genetic analysis as described below. As shown in Table 1,
APW enrichment at 37°C overnight or incubation at 40°C
for 6–8 hours, or both, enhanced the rate of isolation of V.
cholerae O1 from samples. PCR analysis of the key viru-
lence genes showed that 3 (43%) of the 7 isolates, all from
water, were positive for key virulence genes, including
cholera toxin genes and tcpA genes, and that 4 (57%) iso-
lates exhibited no cholera toxin bacteriophage (CTXΦ)–re-
lated genes (23; Table 2). To further assess the PCR results,
we sequenced DNA flanking the CTXΦ from 1 strain, Env-
9 (Table 2). Sequence data corroborated PCR results that
indicated that Env-9 lacked CTXΦ.
Physical parameters for the environmental water sam-
ples are summarized in Table 3. Because the sites varied
from mountains to floodplain to estuaries, there was rela-
tively wide variability in salinity (0–21.6 g/L), pH (6.4–
8.6), and temperature (24.3–33.7°C). Temperatures tended
to increase as rivers approached the sea. As shown in Fig-
ure 2, mean water temperature from all sites showed evi-
dence of seasonal variation. Measurement of rainfall was
available for the region as a whole (Figure 3). However,

site-specific rainfall data were not available; consequently,
rainfall was not included in the regression models.
Isolation of V. cholerae O1 strains was most common
from the sites at the mouths of the Momance and Gressier
Rivers (Figure 1, panel A). In a conditional logistic regres-
sion analysis with water quality factors (Table 4), the only
variable that emerged as statistically significant was wa-
ter temperature (odds ratio 2.14, 95% CI 1.06–4.31); all
isolations of V. cholerae O1 (toxigenic and nontoxigenic)
occurred at water temperatures of >31°C. As shown in
Figure 3, there was evidence that V. cholerae O1 isolation
was more common in the environment preceding epidemic
peaks of disease among humans; however, numbers of iso-
lations were too small to permit statistical analysis. Of 179
samples, the only V. cholerae O1 isolate from aquatic ani-
mals or plants was from a shrimp sample and was nontoxi-
genic; it was collected simultaneously with a water sample
that was also positive for nontoxigenic V. cholerae O1.
Non-O1 V. cholerae was much more common in the
environment than V. cholerae O1 strains and was isolated
from 56 (31%) of 179 water samples. As observed with O1
strains, isolations were more common at the mouths of the
rivers and in estuarine areas (Figure 1, panel B); however,
the non-O1 strain was found farther upriver than were O1
strains and was isolated from several sites in the mountains.
Non-O1 strains were isolated from all sites that were also
positive for O1 strains. Non-O1 strains were isolated in
all months, without an obvious association with regional
Vol. 20, No. 3, March 2014 359
Table 1. Effect of diverse enrichment

conditions on the isolation
of culturable Vibrio cholerae O1 strains from aquatic
reservoirs in
the Gressier and Leogane regions of Haiti
Culture results after alkaline peptone water
enrichment
Strain ID 37°C (6–8 h) 37°C (18–24 h) 40°C (6–8 h)
Env-9 - - +
Env-90 - - +
Env-94 + - +
Env-122* + - -
Env-383 - + -
Env-390 + - -
Env-114* - + +
*Env-122 and env-114 were isolated from water and a
shrimp sample,
respectively, from a single sampling site at a single isolation
round.
RESEARCH
rainfall totals or cholera incidence. In a conditional logistic
regression analysis, isolation of non-O1 strains was signifi-
cantly associated (p<0.05) with higher water temperature
and moderate levels of dissolved oxygen (Table 4).
Discussion
Before this study, isolation of 2 toxigenic V. cholerae

O1 strains from large-volume water samples (30 L) was
reported in the Artibonite region (24); other studies at that
time suggested that V. cholerae O1 strains were not pres-
ent, or present at only minimal levels (2,25) in the envi-
ronment in Haiti. In contrast, we isolated ctx-positive and
ctx-negative V. cholerae O1 serogroup Ogawa biotype El
Tor strains (Table 1) in the environment at a frequency
comparable to that reported from cholera-endemic areas
such as Bangladesh (17). Our successful isolation of the
microorganism from the environment may reflect localiza-
tion of environmental isolates near Gressier and Leogane,
where our study was conducted; however, we believe that
our findings are more likely to be a reflection of the meth-
od used. Data presented here suggest that, in addition to
conventional APW enrichment, longer APW enrichment
time and enrichment at higher temperatures contributed
to an increased rate of isolation of V. cholerae O1 strains
from aquatic environmental reservoirs (Table 1), resulting
in successful isolation from 1.5-mL water samples. We
also note some issues relating to sample transport: Baron
et al. (25) transported their water samples on ice in cool-
ers; our samples were transported at room temperature.
As has been reported, Vibrio spp. are extremely sensitive
to low temperatures (26), and in our experience, transport
of samples on ice resulted in a marked reduction in isola-
tion rates.
Water from which we isolated V. cholerae spp. tended
to have been sampled at the point where rivers meet the
sea, and in adjacent estuarine areas, again following the
patterns reported from Bangladesh (17). Water tempera-
ture was found to be the single physical parameter that was
substantially associated with isolation of these organisms;
higher temperatures were concentrated downriver and in
estuarine areas. For our analysis, we used a conditional

logistic regression model to permit stratification by site.
Although we found very low numbers for V. cholerae O1
isolates (6 positive water samples), results coincided with
the non-O1 results and the exploratory data analysis. In our
studies of aquatic animals likely to be eaten by humans,
we did isolate V. cholerae O1 from shrimp in 1 instance.
The isolate was nontoxigenic; consequently, its association
with disease is unclear.
After analyzing the results of this study, we asked
the following question: has V. cholerae O1 become es-
tablished in environmental reservoirs in Haiti? Toxigenic
V. cholerae O1 strains are clearly present in the environ-
ment, and it may be that the isolates that we identified are
the result of fecal contamination of the environment by
persons infected with V. cholera strains. Although data
are limited, there was at least a suggestion that isolation
of V. cholera strains from environmental reservoirs was
more common at the beginning of epidemic spikes of hu-
man disease (as has been described in association with
environmental reservoirs) (16,17,27) rather than at the
height of epidemics among humans, as might have been
Vol. 20, No. 3, March 2014
Table 3. Summary statistics of environmental water
quality factors in mountains, estuaries, and a
floodplainin Haiti, April 2012–
March 2013
Water quality
No.
specimens

observed
Mean
SD
Minimum
Maximum
pH, log[H+] 176 7.71 0.36 6.4 8.6
Dissolved oxygen, mg/L 176 7.33 1.81 1.23 10.31
Total dissolved solids, mg/L 176 273.8 359.9 24 2,970
Salinity, g/L 176 0.38 1.72 0 21.6
Conductivity (µS/cm) 176 544.1 639.4 230 5,630
Heterotrophic bacteria, log(cfu/mL) 175 4.21 0.60 2.3 5.89
Table 2. PCR analysis of genes of ctx –positive
toxigenic Vibrio cholerae O1 strains and ctx-negative
V. cholerae O1 strain
Strain
PCR
Mismatch amplification
mutation assay PCR
ompW toxR tcpACL tcpAET ctxA ctxB rstRET rstRCL rstCET
rstCCL ctxBCL ctxBET

Env-9* + + + - - - - - - - - -
Env-90 + + - + + + + - - - + -
Env-94 + + - + + + + - - - + -
Env-122*† + + + - - - - - - - - -
Env-383 + + - + + + + - - - + -
Env-390* + + + - - - - - - - - -
Env-114*† + + + - - - - - - - - -
*Indicates ctx-negative V. cholerae O1 isolates.
†Env-122 and env-114 were isolated from water and a
shrimp sample, respectively, from a single
sampling site and at a single isolation round.
expected related to fecal contamination. We also found
non-O1 strains widely distributed throughout the envi-
ronment, including mountain river sites, consistent with
widespread dissemination in environmental reservoirs.
Although we cannot be certain that O1 and non-O1 strains
grow under comparable conditions, the clear establish-
ment of non-O1 V. cholerae strains in environmental res-
ervoirs suggests that conditions are appropriate for growth
of V. cholerae O1 strains. Of potentially greater interest is
the observation that only 3 of the 7 (47%) V. cholerae O1
biotype El Tor strains isolated carried the ctx genes (Table
2). Data from 1 ctx-negative strain (Env-9) was consistent
with absence of the entire CTXΦ. We propose that the
3 isolates that are positive for ctx genes be classified as
circulating V. cholerae altered biotype El Tor strains in
Haiti. To better understand the evolutionary mechanisms
involved, we are performing further sequence analysis of

clinical and environmental strains.
Conclusions
The apparent introduction of toxigenic V. cholerae O1 in
Haiti in 2010, after decades during which no cholera cases were
reported, was unquestionably a public health disaster. If these
O1 strains establish stable environmental reservoirs in Haiti,
in the setting of ongoing problems with water and sanitation,
there is a high likelihood that we will see recurrent epidemics
Vol. 20, No. 3, March 2014 361
Table 4. Conditional logistic regressionanalysis of
water quality factors affecting the occurrence
Vibrio cholerae O1 and non-O1/non-
O139 in aquatic reservoirs, Haiti, April
2012–March 2013
Factor Units No. observations Odds ratio (95% CI) p
value
Presence of V. cholerae O1
Temperature 1°C 47 2.14 (1.06–4.31) 0.033*
pH 1 log[H+] 47 0.01 (0.00–1.81) 0.083
Dissolved oxygen 1 mg/L 47 0.32 (0.08–1.20) 0.091
Total dissolved solids 100 mg/L 47 1.08 (0.95–1.23) 0.258
Salinity 1 g/L 47 1.24 (0.86–1.80) 0.254
Conductivity 100 (µS/cm) 47 1.05 (0.98–1.13) 0.198
Heterotrophic bacteria log (CFU/mL) 47 6.00 (0.57–62.78)
0.135
Presence of V. cholerae non-O1
Temperature 1°C 154 1.36 (1.05–1.76) 0.02*
pH 1 log[H+] 154 0.44 (0.09–2.14) 0.311
Dissolved oxygen 1 mg/L 154 0.50 (0.32–0.79) 0.003*
Total dissolved solids 100 mg/L 154 0.96 (0.86–1.06) 0.413
Salinity 1 g/L 154 1.19 (0.80–1.77) 0.378

Conductivity 100 (µS/cm) 154 0.98 (0.92–1.04) 0.432
Heterotrophic bacteria log (CFU/mL) 153 2.35 (0.95–5.77)
0.063
*p<0.05 were considered statistically significant.
Figure 3. Weekly cholera case
incidence for Ouest Department,
excluding Port-au-Prince, Haiti,
based on data reported to the
Haitian Ministry of Public Health
and Population and regional
precipitation by week during April
2012–March 2013, combined
with percentage of environmental
sites from which V. cholerae
O1 or non-O1/non-O139 were
isolated, by month.
RESEARCH
within the country. These circumstances clearly have implica-
tions for current plans by the Haitian Ministry of Public Health
to eradicate cholera in Haiti within a decade (28). The proposed
implementation of vaccination programs and efforts to improve
water supplies and sanitation will undoubtedly reduce case
numbers, but as long as the causative microorganism is present
in the environment, eradication of the disease will not be pos-
sible. Establishment of environmental reservoirs and recurrent
epidemics may also serve as a potential source for transmission
of the disease to the Dominican Republic and other parts of the
Caribbean (1). Ongoing monitoring of potential environmental
reservoirs in the areas near Gressier and Leogane as well as in
sentinel sites throughout the country will be necessary to assess

this risk and to permit development of rational public health in-
terventions for cholera control.
Acknowledgments
We thank Mohammad Jubair for his technical help with
this study.
This work was supported in part by National Institutes of
Health grants RO1 AI097405 awarded to J.G.M. and a Depart-
ment of Defense grant (C0654_12_UN) awarded to A.A.
Mr Alam is a research scholar at the Department of Envi-
ronmental and Global Health in the College of Public Health
and Health Professions, University of Florida at Gainesville.
His research interests focus on the ecology and epidemiology of
V. cholerae.
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Address for correspondence: Afsar Ali, Department of
Environmental and

Global Health, School of Public Health and Health Professions,
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Gainesville, FL 32610, USA; email: [email protected]
Vol. 20, No. 3, March 2014 363
After epidemic cholera emerged in Haiti in October
2010, the disease spread rapidly in a country devastated
by an earthquake earlier that year, in a population with a
high proportion of infant deaths, poor nutrition, and frequent
infectious diseases such as HIV infection, tuberculosis,
and malaria. Many nations, multinational agencies, and
nongovernmental organizations rapidly mobilized to assist
Haiti. The US government provided emergency response
through the Offi ce of Foreign Disaster Assistance of the US
Agency for International Development and the Centers for
Disease Control and Prevention. This report summarizes
the participation by the Centers and its partners. The efforts
needed to reduce the spread of the epidemic and prevent
deaths highlight the need for safe drinking water and basic
medical care in such diffi cult circumstances and the need
for rebuilding water, sanitation, and public health systems to
prevent future epidemics.
Cholera is a severe intestinal infection caused by strains of the
bacteria Vibrio cholerae serogroup O1 or
O139, which produce cholera toxin. Symptoms and signs
can range from asymptomatic carriage to severe diarrhea,
vomiting, and profound shock. Untreated cholera is fatal in
≈25% of cases, but with aggressive volume and electrolyte
replacement, the number of persons who die of cholera is

limited to <1%. Since 1817, cholera has spread throughout
the world in 7 major pandemic waves; the current and longest
pandemic started in 1961 (1). This seventh pandemic, caused
by the El Tor biotype of V. cholerae O1 and O139, began
in Indonesia, spread through Asia, and reached Africa in
1971. In 1991, it appeared unexpectedly in Latin America,
causing 1 million reported cases and 9,170 deaths in the fi rst
3 years (2). The other biotype of V. cholerae O1, called the
classical biotype, is now rarely seen.
Cholera is transmitted by water or food that has been
contaminated with infective feces. The risk for transmission
can be greatly reduced by disinfecting drinking water,
separating human sewage from water supplies, and
preventing food contamination. Industrialized countries
have not experienced epidemic cholera since the late
1800s because of their water and sanitation systems (3).
The risk for sustained epidemics may be associated with
the infant mortality rate (IMR) because many diarrheal
illnesses of infants spread through the same route. In Latin
America, sustained cholera transmission was seen only in
countries with a national IMR >40 per 1,000 live births (4).
Although cholera persists in Africa and southern Asia, it
recently disappeared from Latin America after sustained
improvements in sanitation and water purifi cation (5,6).
Although the country was at risk, until the recent outbreak,
epidemic cholera had not been reported in Haiti since
the 1800s, and Haiti, like other Caribbean nations, was
unaffected during the Latin America epidemic (7,8).
Haiti: A History of Poverty and Poor Health
Haiti has extremely poor health indices. The life
expectancy at birth is 61 years (9), and the estimated IMR
is 64 per 1,000 live births, the highest in the Western

Hemisphere. An estimated 87 of every 1,000 children born
die by the age of 5 years (9), and >25% of surviving children
experience chronic undernutrition or stunted growth (10).
Maternal mortality rate is 630 per 100,000 live births (10).
Haitians are at risk of spreading vaccine-preventable
diseases, such as polio and measles, because childhood
vaccination coverage is low (59%) for polio, measles-
Lessons Learned during Public
Health Response to Cholera
Epidemic in Haiti and the
Dominican Republic
Jordan W. Tappero and Robert V. Tauxe
11, November 2011 2087
Author affi liation: Centers for Disease Control and Prevention,
Atlanta, Georgia, USA
SYNOPSIS CHOLERA IN HAITI
rubella, and diphtheria-tetanus-pertussis vaccines (9).
Prevalence of adult HIV infection (1.9%) and tuberculosis
(312 cases per 100,000 population) in the Western
Hemisphere is also highest in Haiti (11,12), and Hispaniola,
which Haiti shares with the Dominican Republic, is the only
Caribbean island where malaria remains endemic (13).

Only half of the Haitian population has access to
health care because of poverty and a shortage of health
care professionals (1 physician and 1.8 nurses per 10,000
population), and only one fourth of seriously ill persons are
taken to a health facility (14). Before the earthquake hit
Haiti in January 2010, only 63% of Haiti’s population had
access to an improved drinking water source (e.g., water
from a well or pipe), and only 17% had access to a latrine
(15).
Aftermath of Earthquake
The earthquake of January 12, 2010, destroyed homes,
schools, government buildings, and roads around Port-
au-Prince; it killed 230,000 persons and injured 300,000.
Two million residents sought temporary shelter, many
in internally displaced person (IDP) camps, while an
estimated 600,000 persons moved to undamaged locations.
In response, the Haitian government developed
strategies for health reform and earthquake response
(16,17) and called on the international community for
assistance. The Ministère de la Santé Publique et de la
Population (MSPP) requested assistance from the Centers
for Disease Control and Prevention (CDC) to strengthen
reportable disease surveillance at 51 health facilities that
were conducting monitoring and evaluation with support
from the US President’s Emergency Plan for AIDS
Relief (PEPFAR) (18) and at health clinics for IDPs (19).
MSPP also asked CDC to help expand capacity at the
Haiti Laboratoire National de Sante Publique to identify
reportable pathogens, including V. cholerae (20,21), and
help train Haiti’s future epidemiologic and laboratory
workforce. These actions, supported through new
emergency US government (USG) funds to assist Haiti
after the earthquake, laid the groundwork for the rapid

detection of cholera when it appeared.
Cholera Outbreak
On October 19, 2010, MSPP was notifi ed of a
sudden increase in patients with acute watery diarrhea
and dehydration in the Artibonite and Plateau Centrale
Departments. The Laboratoire National de Sante Publique
tested stool cultures collected that same day and confi rmed
V. cholerae serogroup O1, biotype Ogawa, on October 21.
The outbreak was publicly announced on October 22 (22).
A joint MSPP-CDC investigation team visited 5
hospitals and interviewed 27 patients who resided in
communities along the Artibonite River or who worked
in nearby rice fi elds (23). Many patients said they drank
untreated river water before they became ill, and few had
defecated in a latrine. Health authorities quickly advised
community members to boil or chlorinate their drinking
water and to bury human waste. Because the outbreak
was spreading rapidly and the initial case-fatality rate
(CFR) was high, MSPP and the USG initially focused on
5 immediate priorities: 1) prevent deaths in health facilities
by distributing treatment supplies and providing clinical
training; 2) prevent deaths in communities by supplying oral
rehydration solution (ORS) sachets to homes and urging ill
persons to seek care quickly; 3) prevent disease spread by
promoting point-of-use water treatment and safe storage
in the home, handwashing, and proper sewage disposal; 4)
conduct fi eld investigations to defi ne risk factors and guide
prevention strategies; and 5) establish a national cholera
surveillance system to monitor spread of disease.
National Surveillance of Rapidly Spreading Epidemic
Health offi cials needed daily reports (which established

reportable disease surveillance systems were not able to
provide) to monitor the epidemic spread and to position
cholera prevention and treatment resources across the
country. In the fi rst week of the outbreak, MSPP’s director
general collected daily reports by telephone from health
facilities and reported results to the press. On November
1, formal national cholera surveillance began, and MSPP
began posting reports on its website (www.mspp.gouv.ht).
On November 5–6, Hurricane Tomas further complicated
surveillance and response efforts, and many persons fl ed
fl ood-prone areas. By November 19, cholera was laboratory
confi rmed in all 10 administrative departments and Port-au-
Prince, as well as in the Dominican Republic and Florida
(24,25) (Figure 1). Though recently affected departments in
Haiti experienced high initial CFRs, by mid December, the
CFR for hospitalized case-patients was decreasing in most
departments, and fell to 1% in Artibonite Department (26).
Reported cases decreased substantially in January, and the
national CFR of hospitalized case-patients fell below 1%
(Figure 2). As of July 31, 2011, a total of 419,511 cases,
222,359 hospitalized case-patients, and 5,968 deaths had
been reported.
Field Investigations and Laboratory Studies
To guide the public health response, offi cials
needed to know how cholera was being transmitted,
which interventions were most effective, and how well
the population was protecting itself. Therefore, CDC
collaborated with MSPP and other partners to conduct
rapid fi eld investigations and laboratory studies. Central
early fi ndings included the following.
First, identifying untreated drinking water as the
primary source for cholera reinforced the need to provide

CHOLERA IN HAITI Cholera in Haiti and Dominican Republic
water purifi cation tablets and to teach the population how
to use them. Although most of the population had heard
messages about treating their drinking water, many lacked
the means to do so.
In addition, in Artibonite Department, those with
cholera-like illness died at home, after reaching hospitals,
and after discharge home, which suggests that persons
were unaware of how quickly cholera kills and that the
overwhelmed health care system needed more capacity and
training to deliver lifesaving care. Also, water and seafood
from the harbors at St. Marc and Port-au-Prince were
contaminated with V. cholerae, which affi rmed the need to
cook food thoroughly and advise shipmasters to exchange
ballast water at sea to avoid contaminating other harbors.
The epidemic strain was resistant to many antimicrobial
agents but susceptible to azithromycin and doxycycline.
Guidelines were rapidly disseminated to ensure effective
antimicrobial drug treatment.
Cholera affected inmates at the national penitentiary
in Port-au-Prince in early November, causing ≈100 cases
and 12 deaths in the fi rst 4 days. The problem abated after
the institution’s drinking water was disinfected and inmates
were given prophylactic doxycycline.
Finally, investigators found that epidemic V. cholerae

isolates all shared the same molecular markers, which
suggests that a point introduction had occurred. The
epidemic strain differed from Latin American epidemic
strains and closely resembled a strain that fi rst emerged in
Orissa, India, in 2007 and spread throughout southern Asia
and parts of Africa (27). These hybrid Orissa strains have
the biochemical features of an El Tor biotype but the toxin
of a classical biotype; the later biotype causes more severe
illness and produces more durable immunity (28,29). A
representative isolate was placed in the American Type
Culture Collection, and 3 gene sequences were placed in
GenBank (23).
Training Clinical Caregivers and Community
Health Workers
CDC developed training materials (in French and
Creole) on cholera treatment and on November 15–16
held a training-of-trainers workshop in Port-au-Prince for
locally employed clinical training staff working at PEPFAR
sites across all 10 departments. These materials were also
posted on the CDC website (www.cdc.gov/haiticholera/
traning). The training-of-trainers graduates subsequently
led training sessions in their respective departments; 521
persons were trained by early December.
During the initial response ≈10,000 community
health workers (CHWs), supported through the Haitian
government and other organizations, staffed local fi rst aid
clinics, taught health education classes, and led prevention
activities in their communities. Training materials for
CHWs developed by CDC were distributed at departmental
training sessions, shared with other nongovernmental
organization (NGO) agencies, and used in a follow-up
session for CHWs held on March 1–3, 2011 (see pages

2162–5). The CHW materials discussed treating drinking
water by using several water disinfection products; how to
triage persons coming to a primary clinic with diarrhea and
11, November 2011 2089
Figure 1. Administrative departments of Haiti affected by the
earthquake of January 12, 2010; the path of Hurricane Tomas,
November 5–6, 2010; and cumulative cholera incidence by
department as of December 28, 2010.
Figure 2. Reported cases of cholera by day, and 14-day
smoothed
case-fatality rate (CFR) among hospitalized cases, by day,
Haiti,
October 22, 2010–July 25, 2011. UN, United Nations; CDC,
Centers for Disease Control and Prevention; PAHO, Pan
American
Health Organization; MSPP, Ministère de la Santé Publique et
de
la Population.
SYNOPSIS CHOLERA IN HAITI
vomiting; making and using ORS; and disinfecting homes,
clothing, and cadavers with chlorine bleach solutions.
Materials were posted on the CDC website as well.
Working with Partners to Increase
Capacity for Cholera Treatment
Supply logistics were daunting as cholera spread
rapidly across Haiti. Sudden, unexpected surges in cases

could easily deplete local stocks of intravenous rehydration
fl uids and ORS sachets, and resupplying them could
be slow. The national supply chain, called Program on
Essential Medicine and Supplies, was managed by MSPP,
with technical assistance from the Pan American Health
Organization, and received shipments of donated materials
and distributed them to clinics.
Early in November the USG provided essential
cholera treatment supplies through the US Agency for
International Development’s Offi ce of Foreign Disaster
Assistance (OFDA) to the national warehouse and IDP
camps. CDC staff also distributed limited supplies to
places with acute needs. To complement efforts by MSPP
and aid organizations to establish preventive and treatment
services, OFDA provided emergency funding to NGO
partners with clinical capacity.
When surveillance and modeling suggested that the
spread of cholera across Haiti could outpace the public
health response, the USG reached out to additional partners
to expand cholera preventive services and treatment
capacity. PEPFAR clinicians were authorized to assist with
clinical management of cholera patients and participated
in clinical training across the country. In December, CDC
received additional USG emergency funds and awarded
MSPP and 6 additional PEPFAR partners $14 million to
further expand cholera treatment and prevention efforts
through 4,000 CHWs and workers at 500 community oral
rehydration points. Funds were also used to expand cholera
treatment sites at 55 health facilities. In addition, CDC
established the distribution of essential cholera supplies to
PEPFAR partners through an existing HIV commodities
supply chain management system.
Improvements in Water, Sanitation, and Hygiene

To increase access to treated water and raise awareness
of ways to prevent cholera, a consortium of involved NGOs
and agencies, called the water, sanitation, and hygiene
cluster, met weekly. Led by Haiti’s National Department
of Drinking Water and Sanitation and the United Nation’s
Children’s Fund, the members of this cluster targeted all
piped water supplies for chlorination and began distributing
water purifying tablets for use in homes throughout Haiti.
CDC helped the National Department of Drinking Water
and Sanitation monitor these early efforts with qualitative
and quantitative assessments of knowledge, attitudes,
and practices. Emergency measures, especially enhanced
chlorination of central water supplies, were expanded in
the IDP camps because of the perceived high risk. OFDA
and CDC provided water storage vessels, soap, and large
quantities of emergency water treatment supplies for
households and piped water systems. Distributing water
purifying tablet supplies to diffi cult-to-reach locations
remained a challenge.
Educating the Public
Beginning October 22, MSPP broadcast mass media
messages, displayed banners, and sent text messages
encouraging the population to boil drinking water and seek
care quickly if they became ill. Early investigations affi rmed
the public’s need for 5 basic messages:1) drink only treated
water; 2) cook food thoroughly (especially seafood);
3) wash hands; 4) seek care immediately for diarrheal
illness; 4) and give ORS to anyone with diarrhea. In mid
November, focus group studies in Artibonite indicated that
residents were confused about how cholera was spreading

Figure 3. Educational poster (in Haitian Creole) used by the
Haitian Ministère de la Santé Publique et de la Population
(MSPP)
to graphically present the ways of preventing cholera. DINEPA,
Direction Nationale de l’Eau Potable et d’ Assainessement;
UNICEF,
United Nations Children’s Fund; ACF, Action Contre la Faim.
CHOLERA IN HAITI Cholera in Haiti and Dominican Republic
and how to best prevent it, but they understood the need to
treat diarrheal illness with ORS, how to prepare ORS, and
how to disinfect water with water purifi cation tablets (30).
Posters provided graphic messages for those who could
not read (Figure 3). On November 14, Haitian President
René Préval led a 4-hour televised public conference to
promote prevention, stressing home water treatment and
handwashing, and comedian Tonton Bichat showed how
to mix ORS.
Cholera Epidemic in Dominican Republic
Compared with Haiti’s experience, the epidemic
has been less severe in Dominican Republic. Though
the countries share the island, conditions in Dominican
Republic are better than in Haiti: the IMR is one third that of
Haiti, gross domestic product per capita is 5× greater, and
86% of the population has access to improved sanitation.
Within 48 hours of the report of cholera in Haiti, the
Ministry of Health in the Dominican Republic and CDC
established the capacity for diagnosing cholera at the
national laboratory; the fi rst cholera case was confi rmed

Risk Factors Early in the 2010 Cholera Epidemic, Haiti.docx

Risk Factors Early in the 2010 Cholera Epidemic, Haiti.docx

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