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| Agenda Item 9 | CAP 04/6 |
FAO/WHO Regional Conference on Food Safety for Asia and Pacific
Seremban, Malaysia, 24-27 May 2004
FOODBORNE DISEASE MONITORING AND SURVEILLANCE SYSTEMS
(Paper prepared by the Government of Malaysia)
1. INTRODUCTION
2. FOODBORNE DISEASE SURVEILLANCE
3. NEXT STEPS
4. CONCLUSION
5. RECOMMENDATIONS
6. REFERENCES:
ANNEX 1 - CATEGORIES OF FOODBORNE DISEASE SURVEILLANCE
ANNEX 2 - FINAL GENERAL RECOMMENDATIONS
Food borne diseases are usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. They have a significant impact on people’s health, along with economic consequences, and represent a growing public health problem. Outbreaks of food borne disease attract media attention and raise consumer concern in developing as well as developed countries.
The global incidence of food borne diseases is difficult to estimate although many people fall ill and die as a result of eating unsafe food. In industrialized countries, 30% of the people are affected by food borne diseases annually, and the problem is likely to be even more widespread in developing countries. WHO reported that in 2000, 2.1 million people died from diarrhoeal diseases, most of whom were children in the less developed countries. For example, in the United States of America (USA), 76 million cases of food borne diseases resulting in 325, 000 hospitalizations and 5,000 deaths were estimated to occur each year, while medical costs and loss of productivity were estimated as USD 35 billion (1997). The cholera outbreak in Peru in 1991 resulted in the loss of USD 500 million in fish and fishery export for that year while in Japan an outbreak of Escherichia coli O157:H7, an emerging food borne pathogen which presents itself as acute bloody diarrhoea and renal failure, had affected over 6,300 school children and resulted in 2 deaths in 1996.
In Malaysia the incidence of notifiable food borne diseases, namely cholera, typhoid, food poisoning, hepatitis A and dysentery is less than 5/100,000 population, sporadic in nature and outbreaks are confined to certain areas only.
The increased incidence of food borne diseases with widespread outbreaks, the emergence of new food borne pathogens and the development of antimicrobial resistance were recognized as threats to our food safety agenda. The factors contributing to the above were globalization of the food supply, advances in food production and processing technologies, changes in agricultural and animal husbandry practices, demographic changes and changes in lifestyle.
The true dimension of the burden of food borne diseases is still unknown as a result of poor documentation and absence of reliable data, thus limiting our understanding of its public health importance and impeding our efforts to secure the resources and support necessary for effective control of food borne diseases.
Improving surveillance on human food borne disease and monitoring of food contaminants will help greatly in establishing and evaluating priorities in the prevention and control of food borne diseases and reduce uncertainties in its mitigation strategies. The 53rd World Health Assembly (WHA) in the year 2000 adopted a resolution to recognize food safety as an essential public health function and called for the development of a Global Strategy for reduction of the burden of food borne diseases. The resolution WHA 53.15 encouraged member states 'to implement and keep national, and when appropriate, regional mechanisms for food borne diseases surveillance’. In 2002, WHO published a document 'WHO Global Strategy for Food Safety: safer food for better health’ to address this issue. The overall objective of strengthening surveillance of food borne disease is to provide member states with the necessary data to reduce the burden of food borne disease by improving their food safety system.
Innovative strategies and methods are needed for surveying food borne disease and food contamination. Development of a strategy to reduce food-related risks requires knowledge about the current situation of food borne diseases at all levels and must be based on best scientific evidence on food borne hazards and the incidence of food borne disease.
Under the World Trade Organization (WTO) Agreement on the Application of Sanitary and Phytosanitary Measures (SPS), WTO Member Countries should ensure that their sanitary or phytosanitary measures are based on a scientific risk assessment, taking into account the risk assessment techniques developed by the relevant international organizations. In this respect, Codex, which is the international reference for food safety under the SPS Agreement, has adopted the Working Principles for Risk Analysis for Application in the Framework of the Codex Alimentarius, whilst Codex is also developing working principles on risk analysis intended for application by governments. Risk analysis is comprised of risk assessment, risk management and risk communication. Surveillance data is of paramount importance for conducting a risk assessment and eventually for formulating risk management options and implementing risk communication.
Food borne disease surveillance assists in the assessment of the burden of food borne diseases, identification of public health priorities, setting of policies, evaluating program performance and the prevention, detection and control of outbreaks and in the process stimulating research. It may also identify emerging food safety issues.
All countries have different public health systems, giving rise to a wide variation in surveillance systems, with each having a different focus within the realm of food borne diseases. In the year 2002, a WHO consultation on methods for food borne disease surveillance in selected sites had reviewed and grouped the existing food borne disease surveillance systems into 4 categories according to their capacity to generate information (refer to ANNEX 1). It varied from one with no formal surveillance to that of an integrated food chain surveillance system. A country may be primarily within one category but may have surveillance elements from more than one category. Surveillance of food borne diseases may also be part of a national notifiable communicable disease system. However as there is no clear 'best-methods' of surveillance at the moment, the WHO consultative meeting recommended 5 actions to be taken to strengthen the food borne disease surveillance system. (Refer to ANNEX 2).
In Malaysia the current mandatory notification of certain priority food borne diseases has been useful for surveillance, but is inadequate in the event of new emerging food borne diseases. The current surveillance data collected is mainly through physician-based surveillance and outbreak investigations as there is no mandatory requirement for notification from laboratories. Through this system, notification is received from government health facilities consisting of health centers, outpatient departments and hospitals and also from the private hospitals and general medical practitioners. The food borne diseases included in this list are cholera, typhoid and paratyphoid fevers, viral hepatitis A, food poisoning and dysentery.
A systematic approach for the early detection of unknown aetiological agents and notification is therefore needed. The Ministry of Health, Malaysia has produced a manual on a syndromic approach to infectious disease notification and laboratory investigation which complements the other existing specific disease notifications and is useful for rapid response to newly emerging and reemerging diseases. Here the notification is based on a syndrome, not on a specific disease, and the one related to food borne diseases is the “National Acute Gastroenteritis Surveillance”. The Ministry of Health also conducts laboratory- based surveillance of specific infectious diseases and includes food borne diseases due to Salmonella spp., Shigella spp., Salmonella typhi and Vibrio spp..
In Malaysia the facilities of Pulse Field Gel Electrophoresis (PFGE) DNA fingerprinting and gel documentation are already available in the public health and university research laboratories. However, some of the problems and challenges associated with PFGE are the standardization of protocols, reagents, chemicals, electrophoretic conditions, cost and lack of sufficient trained personnel. The realization of a national PulseNet Malaysia will require training of personnel in the use of the standardized protocols so that DNA fingerprints are comparable between laboratories and between countries for rapid identification of clusters of food borne pathogens in case of disease outbreaks. PulseNet is not just about PFGE, but rather a communication network for personnel from the laboratories, surveillance, and epidemiological units to rapidly recognize an imminent food borne disease outbreak.
Improper food handling and unhygienic practices among food handlers have contributed to food poisoning episodes. The Ministry of Health, Malaysia has facilitated a basic training programme on food hygiene and sanitation that food handlers could undergo. Currently the Code of Practice for Food Hygiene and By-Laws of the Local Authority provide general and specific hygienic requirements for food premises. The proposed Food Hygiene Regulations, which is in the process of gazettment, requires that all food handlers be trained by institutes accredited by the Ministry of Health. The Ministry of Health also promotes the use of food safety assurance systems such as HACCP, GMP, and GHP in food industries. The implementation of food safety measures, for example hazard analysis and critical control point systems (HACCP), from farm to table, along with certification of food/farm service outlets using national standards for food safety and introduction of continuous employee training on safe food preparation would greatly reduce contamination of food.
In Malaysia, the Department of Veterinary Services (DVS) conducts a national surveillance program for food borne pathogens associated with livestock products, namely Salmonella, E.coli O157, Campylobacter, Yersinia and Vancomycin-resistant Enterococci (VRE). The Epidemiology and Veterinary Medicine Division, DVS has formulated several diseases surveillance, control, monitoring and eradication programs/protocols of livestock /zoonotic diseases such as for Salmonella, Avian Influenza, VRE, Brucella, Tuberculosis, Johne’s Disease, Nipah Virus and Bovine Spongiform Encephalopathy (BSE).
Besides disease control, eradication and disease free zone programs/protocols, a Livestock Farm Accreditation Scheme has also been implemented. The criteria of the scheme includes an infrastructure protocol, biosecurity protocol, Flock/ Herd Health Program, Good Animal Husbandry Practices, control of drug usage, labeling and trace back system and quality system. The implementation of the scheme will ensure a safe food supply.
Sources of surveillance data for food borne diseases include disease notifications, laboratory reports, environmental indices (food establishment inspection sources; agriculture, veterinary and food analyses), outbreak investigation reports, research studies, morbidity reports, case investigations, sentinel reports, surveys, census and media reports. A considerable amount of information on causative agents, disease characteristics and vehicles of transmission collected by several agencies could be successfully used to decrease the incidence of food borne disease.
Malaysia convened a workshop on this subject from 7-9 July 2003, with the discussion centering on the setting up of a regional laboratory network. The following strategies were agreed upon:
In the Philippines, a project to improve laboratory-based surveillance for food borne pathogens has been started in conjunction with existing surveillance programs. The systems are independent of each other and, as of now, data is not systematically integrated. The project aims to integrate these systems to create a Food borne disease surveillance system that will include antimicrobial resistance data. Microbiologists recently received training in Salmonella serotyping and anti-sera for performing this and forwarding all isolates to the Research Institute of Tropical Medicine.
Viet Nam is currently conducting a study to enhance the capacity to conduct food borne disease surveillance and determine the burden of food borne diseases. The executing agency is the Viet Nam Ministry of Health with supervision from CDC and guidance from WHO's Western Pacific Regional Office. This project comprises four studies:
Fiji, in collaboration with Fiji Ministry of Health, the Fiji School of Medicine, the Western Pacific Regional Office of the World Health Organization, and the Centers for Disease Control and Prevention, has recently developed a national collaborative non-Typhi Salmonella surveillance and laboratory support program. It is designed to provide technical and procedural information for all relevant public health personnel on the surveillance of patients found to have non-Typhi Salmonella and includes specific procedures that need to be carried out to determine the source of infection and associated risk factors.
The USA, the United Kingdom, Australia and the Netherlands have developed an active national surveillance of food borne diseases. In the USA, the Food borne Disease Surveillance Network (US FoodNet) is a collaborative project between the Centers for Disease Control and Prevention (CDC), US Department of Agriculture (USDA) and US Food and Drug Administration (FDA) and was set up in 1996. It is a network of nine sentinel sites conducting active surveillance for a number of food borne pathogens and it measures the burden of illness, determines the source of infection through large case-control studies of sporadic cases and also evaluates the impact of control measures on these infections. Australia established OzFoodNet in 2000 as a collaborative project with the state and territorial health authorities to provide better understanding of the causes and incidence of food borne diseases in the community and to provide an evidence base for policy formulation.
The surveillance capacity to detect widespread outbreaks in the USA has dramatically improved in recent years with PulseNet USA, a national molecular sub-typing network of food borne pathogens. PulseNet is able to compare online results from different laboratories with each other and with a nationwide database. When a cluster is flagged, a detailed epidemiological investigation can often determine the source. PulseNet has gone ‘international’ with extension to other countries, namely PulseNet Canada, PulseNet Europe, PulseNet New Zealand and most recently, PulseNet Asia Pacific.
At the ASEAN level, pursuant to the ASEAN Leaders Meeting on SARS held on 29 April 2003 and ASEAN+3 Health Ministers Meeting on SARS held from 10-11 June 2003, efforts are being undertaken to strengthen collaboration and networking in the surveillance of infectious diseases in this region. Three health projects were identified for strengthening regional cooperation. Thailand was nominated to coordinate the strengthening of disease surveillance, Indonesia to strengthen the ASEAN disease surveillance Net and Malaysia to coordinate the strengthening of laboratory capacity and quality assurance for infectious disease surveillance among ASEAN+3 countries.
At the international level, the WHO Global Salmonella Surveillance Network (WHO Global Salm-Surv) was initiated in the year 2000 to enhance the capacity and quality of Salmonella isolation, identification, serotyping and antimicrobial resistance testing throughout the world. The network consists of institutions and individuals in human health (epidemiologists and microbiologists), veterinary and food-related disciplines. Activities include regional training for microbiologists, external quality assurance and reference testing, a moderated electronic discussion group and a web-based databank containing an annual summary of laboratory results of salmonella serotypes.
WHO Global Salm-Surv has also conducted to training courses for microbiologists in China and will be conducting a third course in 2004 for epidemiologists. There are also plans to develop a burden of illness study, similar to that being performed in Viet Nam. This should be coordinated with any action by WHO and the World Bank.
In the era of information and communication technology (ICT), exchange of information is easier and faster. The utilization of ICT will enhance the surveillance system to be more efficient and effective. Networking, network of networks, on-line reporting, and electronic discussions, to name a few, are ways for various agencies to utilize this technology to the benefit of food borne disease surveillance at various levels.
Effective and efficient food borne disease surveillance will help ensure the quality and safety of food consumed. It should have a global approach in order to enhance the detection and response of food borne illness and act as an early warning system for any outbreak or crisis which may occur at any level, i.e. national, regional or international. Therefore the system should be comprehensive and integrated with food monitoring data along the entire feed-food chain. This would result in robust surveillance and allow appropriate priority setting and public health intervention. Currently, several agencies and stakeholders from multiple disciplines at various levels are involved in the surveillance of food borne diseases, namely Ministries of Health, Veterinary Services, Agriculture and Fisheries, Food industries, Universities, laboratories. While most of the agencies work independently of each other, there should be attempts to collaborate and coordinate the related activities of these agencies so that a unified surveillance system can emerge.
To strengthen and enhance the existing food borne disease surveillance systems, WHO should play the leadership role in guiding member countries with a clear vision and mission. The objectives and strategies established should be acceptable to all member countries, facilitating their implementation of the strategies and their commitment. It has been observed that political commitment from member countries is vital in ensuring the success and sustainability of health programmes implemented, due to the complexity of the interactions involved.
For our existing food borne disease surveillance system to be strengthened, coordinated activities among all sectors dealing with food borne disease surveillance and food safety are of paramount importance. Recognized and standardized methods of surveillance, with epidemiologically- sound and suitable technology will be needed to ensure a functional system. The usage of ICT networking for efficient and effective communication will further enhance and sustain a successful surveillance system. Coordinating centers should be selected based on the level of epidemiological and laboratory facilities and technical expertise available. The centers should be made responsible for conducting training and research in epidemiology as well as laboratory methodology and surveillance.
Innovative strategies and methods are needed for surveying food borne disease and food contamination. Studies linking pathogens in food to the disease in humans would help quantify the risk of food borne diseases. Collaboration among all sectors dealing with food borne disease surveillance and food safety is essential for a meaningful risk analysis outcome. In addition, a laboratory- based surveillance system having networking facilities at the regional and international levels could be utilized in providing food borne disease surveillance information on new emerging pathogens using the modern framework of risk analysis.
In the lesser developed and developing countries where the surveillance system of food borne diseases may be non- existent or not systematic, resources for setting up or strengthening of these surveillance systems should be considered. The issue of manpower, technical expertise, laboratories and technological infrastructure as well as cost effectiveness of the system should be given due emphasis.
The capacity building component in surveillance of food borne diseases in these countries may need to be considered, not only at the national level but also extended to regional and international levels. Capacity building with sufficient resources for infrastructure improvements and development of technical expertise should be considered, especially in the underdeveloped and developing countries. Efforts should also be taken to facilitate the sharing of knowledge, skill and technical expertise related to food borne disease surveillance. Financial constraints posed in measuring the true burden of food borne diseases could be overcome with the establishment of sentinel sites.
Last but not least, food borne diseases should be integrated into the revision of International Health Regulations. The development and enforcement of such legislation will also need the coordination and cooperation among different governmental agencies such as agriculture, fisheries, veterinary services and health.
Food borne diseases are an important public health problem as it not only affects human health, but also has a significant impact on economic and trade issues. The global changes affecting population growth, lifestyle, international food trade, food production and processing, agricultural and animal husbandry practices and antimicrobial resistance have posed a threat to the emergence of food borne diseases. As most of the food borne diseases are not reported, the true dimension of the problem is unknown. The added absence of reliable data on the burden of food borne diseases impedes understanding of its public health importance, although recently publicized outbreaks of food borne diseases have attracted the attention of consumers and policy makers to food safety issues.
Surveillance of food borne diseases provides valuable information in the estimation of the burden of food borne diseases and in the rapid detection and response to outbreaks. For it to be effective, surveillance of food borne diseases has to be integrated with food monitoring data along the entire food chain from farm to table, thus improving the ability to link the pathogen in food to the disease in humans. It must be emphasized that strong leadership with political commitment and collaboration and coordination of activities of the related agencies at the national, regional and global levels are of paramount importance in strengthening and enhancing the existing surveillance systems and in the process, lowering the risk of food borne diseases.
Countries of the region should:
Global Surveillance of food borne disease: Developing a strategy and its interaction to risk analysis. Report of a WHO Consultation. Geneva, Switzerland, 26-29 Nov 2001. WHO/CDS/CSR/EPH/2002.21
Methods for food borne disease surveillance in selected sites: Report of a WHO consultation. Leipzig, Germany, 18-21 March 2002. WHO/CDS/CSR/EPH/2002.22
OzFoodNet: A health network to enhance the surveillance of food borne diseases in Australia. http://www.ozfoodnet.org.au/index.htm
The Present state of food borne disease in OECD countries. J. Rocourt, G. Moy, K. Vierk, J. Schlundt. WHO 2003.
Updated Guidelines for Evaluating Public Health Surveillance Systems.
Recommendations from the Guidelines Working Group. MMWR July 27, 2001/50 (RR13);1-3
WHO Fact Sheet 124.. Emerging Food borne Diseases. Revised January 2002
WHO Food borne Disease. http://www.who.int/foodsafety/foodborne_disease/en/
WHO Global Salmonella Surveillance Site. http://www.who.int/salmsurv/en/
WHO global strategy for food safety : safer food for better health. (Food Safety Issues). WHO. Geneva 2002.
Category 1 No formal surveillance
Description of system
This situation typically exists in countries with political instability, recent history of war, or extreme poverty. The public health system is very low priority or non-existent. Some elements of surveillance may be undertaken by outside agencies.
Data elements
None.
Information expected
Large or unusual outbreaks may be detected and investigated by an outside agency (e.g., non-governmental organizations).
Category 2 Syndromic surveillance
Description of system
Syndromic surveillance is the collection, analysis and interpretation of syndromic data (e.g., diarrhea or food poisoning) from at least selected sites. The surveillance system should use standard case definitions for classifying syndromes. Data should be routinely reported, collated at a central level and promptly disseminated to the public health community. These systems may function with or without laboratory capacity (ministry of health or hospital) but there is no formal laboratory-based surveillance system.
Data elements
Case counts (e.g., see WHO cholera guidelines).
Information expected
Trends over time, seasonal variation.
Define at-risk and high-risk populations.
Recognition of point source outbreaks at the local level.
Recognition of large or unusual outbreaks at the national level.
Category 3 Laboratory-based surveillance
Description of system
Laboratory-based surveillance is the collection, analysis and interpretation of laboratory data from at least selected sites. The surveillance system should use standard case definitions for classifying diseases. Laboratories should use standardized methods for pathogen identification with recognized international quality assurance systems. Data should be routinely reported, collated at a central level and promptly disseminated to the public health community. Laboratory-based surveillance provides higher quality data that syndromic surveillance; countries should strive to develop this type of surveillance system.
Data elements
Etiologic identification
Etiologic agent-specific case counts
Pathogen characterization (e.g., serotyping, antibiogram, etc.)
Information expected
Etiologic agent-specific trends over time, seasonal variation
Define at-risk and high-risk populations
Recognition of point source at the local and diffuse outbreaks at the national level
Category 4 Integrated food-chain surveillance
Description of system
Integrated food-chain surveillance (IFCS) is the collection, analysis, and interpretation of data from animals, food, and humans. The surveillance system should use standard case definitions for classifying diseases. Data should be routinely reported, collated at a central level and promptly disseminated to the public health community. IFCS allows the attribution of burden of illness to specific food categories through the use of detailed information from monitoring food and animals.
Data elements
Etiologic identification
Etiologic agent-specific case counts in the population
Etiologic agent-specific prevalence in animals and foods
Pathogen characterization (e.g., serotyping, antibiogram, etc.)
Community-level case counts
Information expected
Etiologic agent-specific trends over time, seasonal variation
Reliable incidence rates
Define at-risk and high-risk populations
Recognition of point source at the local and diffuse outbreaks at the national level
Ability to use food and/or animal data to generate hypotheses for human disease outbreaks
Comprehensive estimates of burden of food borne disease
Ability to assess the effectiveness of food safety policy interventions
Ability to attribute burden of food borne disease by food category
Ability to detect and control hazards in food
Ability to recognize emerging pathogens in animal