Appendix A: Disease-Specific Chapters - Chapter: Cholera Revised January 2014 - Infectious Diseases Protocol
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Infectious Diseases Protocol Appendix A: Disease-Specific Chapters Chapter: Cholera Revised January 2014
Cholera
Communicable
Virulent
Health Protection and Promotion Act, Section 1 (1)
Health Protection and Promotion Act:
Ontario Regulation 558/91 – Specification of Communicable Diseases
Health Protection and Promotion Act:
Ontario Regulation 559/91 – Specification of Reportable Diseases
1.0 Aetiologic Agent
Cholera is caused by toxigenic strains of Vibrio cholerae, which is a gram-negative, curved
rod that is motile and has many serogroups.1 Only the toxin producing serogroups O1, O139
cause epidemics. However, non-toxigenic serotypes such as O141 can cause sporadic
illness.2
2.0 Case Definition
2.1 Surveillance Case Definition
See Appendix B
2.2 Outbreak Case Definition
The outbreak case definition varies with the outbreak under investigation. Consideration
should be given to the provincial surveillance case definition and the following criteria when
establishing an outbreak case definition:
1. Clinical, laboratory and/or epidemiological criteria;
2. The time frame for occurrence;
3. The geographic location(s) or place(s) where cases live or became ill/exposed;
4. Special attributes of cases (e.g. age, underlying conditions) and/or etiologic agent); and,
5. Further strain typing (e.g. serotype) as appropriate which may be used to support linkage.
Outbreak cases may be classified by levels of probability (i.e. confirmed, probable and/or
suspect).
Note: Cholera is not endemic to Canada. However, clusters can occur among travellers
returning from cholera endemic locales and among their household contacts.
3.0 Identification
3.1 Clinical Presentation
Most persons infected with V.cholerae are asymptomatic although the bacterium can be shed
in their feces for 7-14 days. When illness does occur, infection causes only mild or moderate
diarrhea in roughly 90% of individuals. In 5-10% of cases, infected individuals develop
2severe, watery diarrhea and vomiting. Stools are typically colourless with flecks of mucous
referred to as “rice water” diarrhea.2 The resulting loss of fluids in an infected individual can
rapidly lead to severe dehydration. If not treated, death can occur within hours.3
3.2 Diagnosis
See Appendix B for diagnostic criteria relevant to the case definition.
For further information about human diagnostic testing, contact the Public Health Ontario
Laboratories or refer to the Public Health Ontario Laboratory Services webpage:
http://www.publichealthontario.ca/en/ServicesAndTools/LaboratoryServices/Pages/default.as
px
4.0 Epidemiology
4.1 Occurrence
Cholera is not endemic to Canada and cases in Ontario are directly or indirectly associated
with travel to endemic regions of the world. In recent years, outbreaks have been reported in
areas of the Caribbean including Cuba, Dominican Republic, and Haiti.4 Five cases were
reported in Ontario from 2007 to 2011, for an average of one case per year (range zero to
three cases).
For more information on infectious diseases activity in Ontario, refer to the current versions
of the Ontario Annual Infectious Diseases Epidemiology Reports and the Monthly Infectious
Diseases Surveillance Report.5, 6
4.2 Reservoir
Humans are the only documented natural hosts, but living V. cholerae organisms can exist in
the aquatic environment.2 The bacterium has been found to exist in environmental reservoirs
such as small crustaceans.
4.3 Modes of Transmission
Cholera is one of the oldest and best understood epidemic diseases. Epidemics and
pandemics are strongly linked to the consumption of fecally contaminated water.1
Ingestion of food or water contaminated with feces or vomitus of cases or carriers;
consumption of raw or improperly cooked seafood, and other foods harvested from estuarine
water or seawater.1 Direct person-to-person transmission has not been documented.2
However, one study suggests that secondary transmission may occur since fifty per cent of
household contacts usually acquire the illness within 2 days of the index case becoming ill.7
4.4 Incubation Period
From a few hours to 5 days, usually 2-3 days.1
4.5 Period of Communicability
For the duration of the stool-positive stage, usually until 2-3 days after recovery, however,
carrier state may persist for months. Appropriate antibiotics can shorten the period of
communicability, but are not recommended for treatment.1
34.6 Host Susceptibility and Resistance
Susceptibility is variable; gastric achlorydria and the lack of immunity seen in small children
may increase the risk of illness. Breastfed infants are at reduced risk of cholera. Cholera
occurs more often in persons with blood type O.1
In endemic areas, most people acquire antibodies by early adulthood. Infection with O1
serotype affords no protection against serotype O139 infection and vice versa. Previous
exposure does not confer immunity against future infection.1
5.0 Reporting Requirements
5.1 To local Board of Health
Individuals who have or may have cholera shall be reported to the medical officer of health
by persons required to do so under the Health Protection and Promotion Act, R.S.O. 1990
(HPPA).8
5.2 To the Ministry of Health and Long-Term Care (the ministry) or Public Health
Ontario (PHO), as specified by the ministry
Cases shall be reported using the integrated Public Health Information System (iPHIS), or
any other method specified by the Ministry within five (5) business days of receipt of
initial notification as per iPHIS Bulletin Number 17: Timely Entry of Cases and Outbreaks.9
The minimum data elements to be reported for each case is specified in the following
sources:
• Ontario Regulation 569 (Reports) under the HPPA;10
• The iPHIS User Guides published by PHO; and,
• Bulletins and directives issued by PHO.
6.0 Prevention and Control Measures
6.1 Personal Prevention Measures
Traveller education:
• Consult with a travel clinic regarding occurrence of cholera and vaccination
recommendations. A number of safe and effective vaccines for cholera are available.
• Stress food and water precautions while travelling in endemic areas.
• Avoid eating raw oysters and undercooked shellfish and fish.
• Disseminate general public health education messages about hand hygiene and food
safety.
6.2 Infection Prevention and Control Strategies
Preventative strategies:
• Use routine practices and additional precautions for hospitalized cases, including contact
precautions for diapered or incontinent persons for the duration of illness.2
4• When possible, hospitalized individuals with diarrhea possibly due to cholera should not
share toilet facilities with other patients.11
Refer to Public Health Ontario’s website at www.publichealthontario.ca to search for the
most up-to-date Provincial Infectious Diseases Advisory Committee (PIDAC) best practices
on Infection Prevention and Control (IPAC). PIDAC best practice documents can be found
at:
http://www.publichealthontario.ca/en/BrowseByTopic/InfectiousDiseases/PIDAC/Pages/PID
AC_Documents.aspx.
6.3 Management of Cases
Investigate cases of cholera to determine the source of infection. Refer to Section 5:
Reporting Requirements above for relevant data to be collected during case investigation.
The following disease-specific information should also be obtained during case management:
• Inquire about cholera vaccination history.
Provide education about the illness and how to prevent the spread of infection as above.
Exclude symptomatic food handlers, healthcare providers*, and day care staff and attendees
until symptom free for 24 hours, or 48 hours after completion of antibiotic or anti-diarrheal
medications.
*If the healthcare setting is a hospital, use the “Enteric Diseases Surveillance Protocol for
Ontario Hospitals” (OHA and OMA Joint Communicable Diseases Surveillance Protocols
Committee, November, 2011) for exclusion criteria:
http://www.oha.com/Services/HealthSafety/Documents/Enteric%20Diseases%20Revised%2
0November%202011.pdf.12
Note: Treatment is under the direction of the attending health care provider.
6.4 Management of Contacts
Meal companions in the 5 days before onset should be assessed for symptoms and advised to
seek medical care if indicated.
Chemoprophylaxis is indicated if the likelihood of secondary transmission among household
contacts is high.2
Management of symptomatic contacts is the same as for cases.
6.5 Management of Outbreaks
Provide public health management of outbreaks or clusters in order to identify the source of
illness, stop the outbreak and limit secondary spread.
Two or more non-travel cases linked by time, common exposure, and/or place is suggestive
of an outbreak.
As per the Infectious Diseases Protocol, 2008 (or as current), outbreak management shall
comprise of but not be limited to the following general steps:
• Confirm diagnosis and verify the outbreak;
• Establish an outbreak team;
5• Develop an outbreak case definition- These definitions should be reviewed during the
course of the outbreak, and modified if necessary, to ensure that the majority of cases are
captured by the definitions;
• Implement prevention and control measures;
• Implement and tailor communication and notification plans depending on the scope of the
outbreak;
• Conduct epidemiological analysis on data collected;
• Conduct environmental inspections of implicated premise where applicable;
• If a food item is suspected to be the cause of the outbreak, identify the origin, along with
the transportation, storage and preparation processes;
• Coordinate and collect appropriate clinical specimens, where applicable;
• Prepare a written report; and,
• Declare the outbreak over in collaboration with the outbreak team.
For more information regarding specimen collection and testing, please see the Public Health
Inspector’s Guide to the Principles and Practices of Environmental Microbiology (or as
current).13
Refer to Ontario’s Foodborne Illness Outbreak Response Protocol (ON-FIORP) for multi-
jurisdictional foodborne outbreaks which require the response of more than two Parties (as
defined in ON-FIORP) to carry out an investigation.
7.0 References
1. Heymann DL, editor. Control of communicable diseases manual. 19th ed. Washington,
DC: American Public Health Association; 2008.
2. American Academy of Pediatrics. Section 3: Summaries of infectious diseases. In:
Pickering LK, Baker CJ, Long SS, McMillan JA, editors. Red book: 2012 report of the
Committee on Infectious Diseases. 29th ed. Elk Grove Village, IL: American Academy
of Pediatrics; 2012: 725-7.
3. Public Health Agency of Canada (homepage on the Internet). Ottawa, ON: Her Majesty
the Queen in Right of Canada; 2003. Notifiable diseases on-line:Cholera. 2003 Dec 11
[cited 2009 Feb 12]. Available from:
http://web.archive.org/web/20101009081310/http://dsol-smed.phac-aspc.gc.ca/dsol-
smed/ndis/diseases/chol_e.html.
4. World Health Organization (homepage on the Internet). Geneva, Switzerland: WHO;
2013. Weekly epidemiological record: cholera articles. 2013 [cited 2013 Aug 27].
Available from: http://www.who.int/cholera/statistics/en/index.html
5. Ontario. Ministry of Health and Long-Term Care. Ontario annual infectious diseases
epidemiology report, 2009. Toronto, ON: Queen’s Printer for Ontario; 2009 (or as
current). Available from:
http://www.health.gov.on.ca/en/common/ministry/publications/reports/epi_reports/epi_re
port_2009.pdf
6. Ontario Agency for Health Protection and Promotion (Public Health Ontario). Monthly
infectious diseases surveillance report. Toronto, ON: Queen’s Printer for Ontario; 2013.
Available from:
6http://www.publichealthontario.ca/en/ServicesAndTools/SurveillanceServices/Pages/Mo
nthly-Infectious-Diseases-Surveillance-Report.aspx
7. Nelson EJ, Nelson DS, Salam MA, Sack DA. Antibiotics for both moderate and severe
Cholera. N Eng J Med. 2011 [cited 2013 Aug 14];364(1):5-7. Available from:
http://www.nejm.org/doi/pdf/10.1056/NEJMp1013771
8. Health Protection and Promotion Act, R.S.O. 1990, c. H.7. Available from:
http://www.e-laws.gov.on.ca/html/statutes/english/elaws_statutes_90h07_e.htm
9. Ontario. Ministry of Health and Long-Term Care. Timely entry of cases and
outbreaks.iPHIS bulletin. Toronto, ON: Queen’s Printer for Ontario; 2012:17 (or as
current).
10. Reports, R.R.O. 1990, Reg. 569. Available from: http://www.e-
laws.gov.on.ca/html/regs/english/elaws_regs_900569_e.htm
11. Ontario Agency for Health Protection and Promotion (Public Health Ontario). Cholera:
information for clinicians: December 1, 2010. Toronto, ON: Queen’s Printer for Ontario;
2010 [cited 2013 Aug 27]. Available from:
http://www.publichealthontario.ca/en/eRepository/Vibrio%20cholera%20clinical%20gui
delines%20final%203.pdf
12. Joint Communicable Diseases Surveillance Protocols Committee, Ontario Hospital
Association; Ontario Medical Association. Enteric diseases surveillance protocol for
Ontario hospitals. Toronto, ON: Ontario Hospital Association; 2011 [cited 2013 Aug 27].
Available from:
http://www.oha.com/Services/HealthSafety/Documents/Enteric%20Diseases%20Revised
%20November%202011.pdf
13. Ontario Agency for Health Protection and Promotion (Public Health Ontario). Public
health inspector’s guide to the principles and practices of environmental microbiology.
4th ed. Toronto, ON: Queen’s Printer for Ontario; 2013 [cited 2013 Aug 27]. Available
from:
http://www.publichealthontario.ca/en/eRepository/Public_Health_Inspectors_Guide_201
3.pdf
8.0 Additional Resources
National Advisory Committee on Immunization; Public Health Agency of Canada. Canadian
immunization guide. 7th ed. Ottawa, ON: Her Majesty the Queen in Right of Canada; 2006.
Available from: http://www.phac-aspc.gc.ca/publicat/cig-gci/index-eng.php.
World Health Organization (homepage on the Internet). Geneva, Switzerland: WHO; 2013.
Global alert and response (GAR): Cholera. 2013 [cited 2009 Feb 7]. Available from:
http://www.who.int/csr/don/archive/disease/cholera/en/index.html.
Travel Health (homepage on the Internet). Ottawa, ON: Her Majesty the Queen in Right of
Canada; 2013. Cholera. 2013 May 22 [cited 2009 Feb 1]. Available from: http://www.phac-
aspc.gc.ca/tmp-pmv/info/cholera-eng.php.
Gregg MB, editor. Field epidemiology. 2nd ed. New York, NY: Oxford University Press;
2002.
7Ontario. Ministry of Health and Long-Term Care. Cholera: fact sheet. Toronto, ON: Queen’s
Printer for Ontario; 2010 [cited 2013 Aug 27]. Available from:
http://www.health.gov.on.ca/en/public/publications/disease/docs/cholera.pdf.
Ontario. Ministry of Health and Long-Term Care. Infectious diseases protocol. Toronto, ON:
Queen’s Printer for Ontario; 2008 (or as current). Available from:
http://www.health.gov.on.ca/english/providers/program/pubhealth/oph_standards/ophs/infdis
pro.html
Ontario Agency for Health Protection and Promotion (Public Health Ontario), Allen VG.
Cholera clinical guidelines. Toronto, ON: Queen’s Printer for Ontario; 2011 [cited 2013 Aug
27]. Available from:
http://www.publichealthontario.ca/en/LearningAndDevelopment/Events/Documents/Cholera
%20Clinical%20Guidelines.pdf
9.0 Document History
Table 1: History of Revisions
Revision Date Document Section Description of Revisions
January 2014 General New template.
Section 9.0 Document History Added.
Title of Section 4.5 changed from
“Susceptibility and Resistance” to “Host
Susceptibility and Resistance”
Title of Section 5.2 changed from “To Public
Health Division (PHD)” to “To the Ministry of
Health and Long-Term Care (the ministry) or
Public Health Ontario (PHO), as specified by the
ministry”
1.0 Aetiologic Agent Changed from “Cholera is caused by toxigenic
strains of Vibrio cholerae, which is a gram-
negative, curved, motile bacillus with many
serogroups. Only serogroups O1, O139 and
O141 cause clinical cholera associated with
enterotoxin” to “Cholera is caused by toxigenic
strains of Vibrio cholerae, which is a gram-
negative, curved rod that is motile and has many
serogroups. Only the toxin producing serogroups
O1, O139 cause epidemics. However, non-
toxigenic serotypes such as O141 can cause
sporadic illness”.
2.2 Outbreak Case Addition of fifth bullet point: “Further strain
Definition typing (e.g. serotype) as appropriate which may
be used to support linkage”
8Revision Date Document Section Description of Revisions
3.2 Diagnosis The following was deleted: “Diagnosis is
confirmed by laboratory isolation of Vibrio
cholerae, serogroups O1 and O139 from feces or
vomitus, or by serology for evidence of recent
infection”.
Addition of direction to contact Public Health
Ontario Laboratories or PHO website for
additional information on human diagnostic
testing.
4.1 Occurrence Entire section revised.
4.2 Reservoir Second sentence added: “The bacterium has
been found to exist in environmental reservoirs
such as small crustaceans”.
4.3 Modes of Addition of the first paragraph: “Cholera is one
Transmission of the oldest and best understood…”
Addition of final sentence to second paragraph:
“However, one study suggests that secondary
transmission may occur…”
4.6 Host Susceptibility Addition of final sentence: “Previous exposure
and Resistance does not confer immunity against future
infection.”
6.1 Personal The following was deleted: “Educate the general
Prevention Measures public and especially food handlers about
careful hand washing after defecation, sexual
contact and before preparing or eating food”.
6.2 Infection Addition of second bullet point: “When possible,
Prevention and hospitalized individuals with diarrhea possibly
Control Strategies due to cholera should not share toilet facilities
with other patients”.
Addition of reference to PIDAC IPAC best
practices documents.
6.3 Management of The requirement to obtain the following
Cases information deleted: “Symptoms and date of
symptom onset, History of travel, Food history
for last 5 days, History of exposure or risk
behaviours, Earliest and latest exposure dates,
Residency/attendance/occupation at a facility or
institution”.
The requirement to “Inquire about cholera
9Revision Date Document Section Description of Revisions
vaccination history” added.
Reference to the OHA and OMA Enteric
Diseases Surveillance Protocol for Ontario
Hospitals added.
6.4 Management of Addition of final sentence “Management of
Contacts symptomatic contacts is the same as for cases”.
6.5 Management of Addition of the following to the third bullet
Outbreaks point: “These definitions should be reviewed
during the course of the outbreak, and modified
if necessary, to ensure that the majority of cases
are captured by the definitions”.
Addition of the eighth bullet point: “If a food
item is suspected to be the cause of the outbreak,
identify the origin, along with the transportation,
storage and preparation processes”.
Addition of final two paragraphs.
7.0 References Updated.
8.0 Additional Updated.
Resources
10© 2014 Queen’s Printer for Ontario
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