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close this bookWHO Recommended Surveillance Standards (WHO; 1999; 157 pages)
View the documentAcknowledgements
View the documentAcronyms
View the documentIntroduction
View the documentNational Coordination of Communicable Disease Surveillance
View the documentExplanatory notes
View the documentSurveillance activities: criteria and WHO Department
View the documentCommunicable disease contacts in Regional Offices
open this folder and view contentsDiseases
close this folderSyndromes
View the documentAcute haemorrhagic fever syndrome
View the documentAcute lower respiratory tract infections (aLRTI) and Pneumonia
View the documentAcute (watery) diarrhoea
View the documentAcute (bloody) diarrhoea
View the documentAntimicrobial resistance
View the documentAnti-tuberculosis drug resistance
View the documentFoodborne diseases
View the documentSexually transmitted diseases/syndromes
View the documentAnnex 1 Software free and in the public domain
View the documentAnnex 2 Proposed surveillance definitions
View the documentAnnex 3 Role and use of Geographic Information Systems (GIS) and mapping for epidemiological surveillance
 

Foodborne diseases

RATIONALE FOR SURVEILLANCE

A foodborne disease is a disease, usually either infectious or toxic in nature, caused by agents that enter the body through ingestion of food or drinking-water. In addition to diseases mentioned in the manual (cholera, hepatitis A, shigellosis, salmonellosis), other foodborne diseases can also be the object of surveillance, which helps to determine the magnitude and trend of foodborne diseases and to monitor and evaluate food safety. Surveillance is also needed for early detection and control of outbreaks, identification of risk factors, and planning and evaluation of interventions.

RECOMMENDED CASE DEFINITION

Clinical case definition

The clinical case definition varies with the specific disease.

Laboratory criteria for confirmation

Isolation of pathogen.

Case classification

 

Suspected: A case that meets the clinical case definition of a specific foodborne disease.

Probable: Not applicable.

Confirmed: A suspected case in whom laboratory investigation confirms the presence of one or more foodborne pathogens in a clinical specimen.

RECOMMENDED TYPES OF SURVEILLANCE

Parallel systems of surveillance may be used, depending on specific surveillance objectives

 

• Routine immediate reporting of case-based data on suspected cases from peripheral level to intermediate level (notifications). Routine weekly reporting of aggregated data on suspected and confirmed cases from peripheral to intermediate and central levels

• Routine weekly case-based or aggregated reporting from laboratories on confirmed cases to intermediate and central levels

• Sentinel surveillance (utilizing reporting physicians or laboratories)*

• Community studies

 

* Sentinel surveillance or community studies can provide detailed epidemiological and microbiological information, and may give a better picture of true incidence and impact of disease in a defined population, but are likely to miss outbreaks and thus do not necessarily represent a valid approach to outbreak detection.

All outbreaks must be investigated and notified to the intermediate and central level.

International: Reports on notifications, laboratory data and outbreaks to be sent to the WHO Global Database on Foodborne Diseases Incidence as well as to regional surveillance programmes. Reports on investigations of specific outbreaks, particularly those implicating a commercial product, to the WHO Global Database on Foodborne Diseases Outbreaks.

 

Note: A minimum data set should be collected on each outbreak at intermediate and central levels. This should be done after the outbreak investigation and should include key variables describing the nature and extent of the outbreak.

RECOMMENDED MINIMUM DATA ELEMENTS

Case-based data at peripheral level

 

• Case classification (suspected/confirmed)
• Unique identifier, age, sex, geographical information
• Date of onset, diagnosis, travel history
• Suspected food, where purchased, prepared, consumed

Aggregated data for reporting

 

• Number of cases by age group, sex, geographical area, week

Case-based data from laboratory

 

• Unique identifier, age, sex, geographical information
• Date of onset, date of specimen
• Specimen type, organism(s) identified

Aggregated data from laboratory

 

• Number of cases by age group and sex, geographical area, week, organism

Outbreaks aggregated data

 

• Number of people at risk/ill/hospitalized/dead
• Geographical information, outbreak setting (e.g., restaurant, hospital, school)
• Date of first and last case
• Food or constituent implicated, causal agent
• Other factors (storage, heating, cross-contamination, food handler, environment)

RECOMMENDED DATA ANALYSES, PRESENTATION, REPORTS

Surveillance data

 

• Frequent review of clinical and laboratory data looking for clusters of cases in time, place or person; all suspected clusters must be investigated to establish whether an outbreak has occurred

• Incidence of disease notifications and laboratory identifications by week, geographical area, organism, age group and sex (map incidence by geographical area if possible)

Outbreak investigation data

 

• Outbreak incidence by month, geographical area, setting, causal agent, attack rate, duration, foods implicated and contributing factors

See: WHO Guidelines for the Investigation and Control of Foodborne Disease Outbreaks, in preparation.

PRINCIPAL USES OF DATA FOR DECISION-MAKING

 

• Determine the magnitude of the public health problem
• Detect clusters/outbreaks on time
• Track trends in foodborne disease over time
• Identify high risk food, food practices and populations for specific pathogens
• Identify emergence of new pathogens
• Guide the formation of food policy and monitor the impact of control measures
• Assess risk and set standards
• Provide information to enable the formulation of health education in food safety

See: Surveillance of foodborne diseases: What are the options? WHO/FSF/FOS/97.3. Food Safety Unit, WHO, 1997, 44 pages.

SPECIAL ASPECTS

Human surveillance should be linked with food safety and control authorities.

Some diseases (e.g., salmonellosis) have a specific surveillance system which requires reference laboratories for detailed serotyping.

CONTACT

Regional Offices

See Regional Communicable disease contacts on section "Communicable disease contacts in Regional Offices".

Headquarters: 20 Avenue Appia, CH-1211 Geneva 27, Switzerland

Food Safety Programme/Protection of human Environment (FOS/PHE)

 

E-mail: motarjemiy@who.ch
Tel: (41 22) 791 3558/3535/2111
Fax: (41 22) 791 4807 attn FSF

Communicable Diseases Surveillance and Response (CSR)

 

E-mail: stohrk@who.int / outbreak@who.ch
Tel: (41 22) 791 2529/2660/2111
Fax: 791 4893
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