foodborne diseases

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World Health House Indraprastha Estate, Mahatma Gandhi Marg, New Delhi-110002, India www.searo.who.int

in the South-East Asia Region

foodborne diseases

Burden of

Globally, billions of people are at risk of foodborne diseases (FBDs) and millions fall ill from these every year. Many die as a result of consuming unsafe food. FBDs can also affect economic development through the tourism, agricultural and food export industries. The South-East Asia Region has the second highest burden of FBDs after the African Region, with more than 150 million cases and 175 000 deaths annually.

The World Health Organization has launched a comprehensive and first of its kind report to estimate the global and regional burden of FBDs. This report will support policy-makers in implementing the right strategies to prevent, detect and manage foodborne risks to improve food safety. It highlights the work of WHO's Regional Office for South-East Asia with national governments on improving surveillance of foodborne diseases and meeting unique local challenges.

9 789290 225034 ISBN 978-92-9022-503-4

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Burden of foodborne diseases

in the South-East Asia Region

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WHO Library Cataloguing-in-Publication data

World Health Organization, Regional Office for South-East Asia.

Burden of foodborne diseases in the South-East Asia Region.

1. Foodborne Diseases 2. Epidemiology 3. Food contamination

ISBN 978-92-9022-503-4 (NLM classification: WC 268)

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Acronyms ...v

Introduction: Foodborne diseases ...1

Foodborne infections ...2

Chemicals and toxins in food ...3

Food allergy ...4

Global burden of foodborne diseases ...5

Objectives ...5

Methodology ...6

Gaps and limitations ...9

Foodborne diseases in the WHO South-East Asia Region...11

Foodborne diseases in under-five children ...13

Conclusions and action points ...17

Annexes 1. Classification of foodborne diseases ...21

2 A guide to national burden of foodborne disease study ...42

3 Categorization of subgroups under WHO regions ...47

Acronyms

CA Codex Alimentarius

DALY disability-adjusted life-year ETEC enterotoxigenic Escherichia coli EPEC enteropathogenic Escherichia coli

FAO Food and Agriculture Organization of the United Nations FBDs foodborne diseases

FERG Foodborne Disease Burden Epidemiology Reference Group GEMS Global Environmental Monitoring System

HAV hepatitis A virus

IHR (2005) International Health Regulations (2005) INFOSAN International Food Safety Authorities Network NTS non-typhoidal Salmonella enterica

POPs persistent organic pollutants sp., spp. species (sing. and plural) WHO World Health Organization

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Introduction: Foodborne diseases

Food is an essential requirement for humans but it can also be a vehicle of disease transmission if contaminated with harmful microbes (bacteria, viruses or parasites) or chemicals/toxins. Globally, billions of people are at risk of foodborne diseases (FBDs) and millions fall ill every year. Many also die as a result of consuming unsafe food.

Foodborne illnesses are mainly caused due to food contamination with harmful bacteria, viruses, parasites, toxins or chemicals. Microbial and chemical risks could be introduced at the farm level (e.g. using water contaminated by industrial waste or poultry farm waste for irrigation of crops). Similarly, such risks may emerge during processing, transportation or storage of food and food products.

While many FBDs may be self-limiting, some can be very serious and even result in death. These diseases may be more serious in children, pregnant women and those who are older or have a weakened immune system. Children who survive some of the more serious FBDs may suffer from delayed physical and mental development, impacting their quality of life permanently. Food allergy is another emerging problem.

A brief description of major FBDs of public health importance is presented in Annex 1.

FBDs are more critical in developing countries due to various reasons, such as use of unsafe water for cleaning and processing of food, poor food production processes and food handling, absence of adequate food storage infrastructure, and inadequate or poorly enforced regulatory standards. The tropical climate in many countries in the Region also favours the proliferation of pests and naturally occurring toxins and increase the risk of contracting parasitic diseases including worm infestations.

FBDs can also affect economic development through the tourism, agriculture and food export industries. In a globalized world, FBDs do not recognize borders. A local incident can quickly become an international emergency due to the speed and range of product distribution, impacting health, international relations and trade. A brief description of foodborne diseases is presented in Annex 1.

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Foodborne infections

When certain disease-causing microbes (bacteria, viruses or parasites) contaminate food, they can cause foodborne illness, often called “food poisoning”. Foods that are contaminated may not look, taste or smell any different from foods that are safe to eat.

Salmonella, Campylobacter, Shigella and Escherichia coli (also called E. coli) are the common bacteria that cause foodborne illnesses. Salmonella is the most common cause of foodborne illnesses and meat, egg and seafood are common food sources for much illnesses. Some foodborne bacteria like Listeria monocytogenes can even grow inside the refrigerator in ready-to-eat food. Staphylococcus aureus bacteria grow in food and produce toxins that cause staphylococcal food poisoning. Viruses that commonly cause foodborne illnesses are norovirus and hepatitis A virus (HAV), which can be transmitted through contaminated water as well as contaminated surfaces.

Foodborne bacteria are often naturally present in food and under the right conditions, a single bacterium can grow into millions of bacteria in a few hours. These bacteria multiply rapidly on foods with lots of protein or carbohydrates when food temperature is between 5 °C and 60 °C, which is often known as the “food danger zone”. Therefore, most foodborne illnesses and outbreaks are reported during the summer months.

Bacteria grow and multiply on some types of food more easily than on others. The types of foods that bacteria prefer include meat, poultry, dairy products, eggs, seafood, cooked rice, prepared fruit and salads. These foods are more likely to be infected by foodborne bacteria but other foods could also be infected or cross-contaminated by them if appropriate food safety measures are not taken during preparation, storage, transportation and handling .

The symptoms of FBDs range from mild and self-limiting (nausea, vomiting and diarrhoea with or without blood) to debilitating and life-threatening (such as kidney and liver failure, brain and neural disorders, paralysis and potentially cancers) leading to long periods of absenteeism from work and premature death. After eating tainted food, abdominal cramps, diarrhoea and vomiting can start as early as one hour or within three days depending on the foodborne pathogen, type of toxin and level of food contamination.

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Chemicals and toxins in food

Food adulteration and falsification are still a problem in countries of the WHO South- East Asia Region where informal food production and distribution systems are deeply entrenched at the community level. Adulteration of food is normally observed in its most crude form where prohibited substances are either added or used to partly or wholly substitute healthy ingredients or to artificially create the impression of freshness in stale food. Adulterants may be in solid form, of chemicals, or liquid and made up of colouring substances. Poisonous colouring agents like auramine, rhodomine b, malachite green and Sudan red are applied on food items for colouring, brightness and freshness. This can damage the liver and kidneys sometimes. These agents also cause stomach cancer, asthma and bladder cancer. Colouring agents such as chrome, tartazine and erythrosine are used in spices, sauces, juices, lentils and oils, causing cancer, allergy and respiratory problems. The calcium carbide of industrial grade used for fruit ripening by unscrupulous traders may contain toxic impurities such as traces of arsenic and phosphorous, which can be quite harmful for the health and can lead to various ailments..

Dioxins are byproducts of industrial processes but could also result from natural phenomena such as volcanic eruptions and forest fires. Human exposure is primarily through food – mainly meat and dairy products, fish and shellfish. These toxins accumulate in humans, especially in body fat. Dioxins are toxic to the thyroid gland and inhibit sperm production, and prolonged exposure leads to accumulation in the body.

The dioxin concentration in breast milk fat directly reflects its concentration in body fat.

Mycotoxins are a group of naturally occurring chemicals produced by certain moulds or fungi. They can grow on a variety of different crops and foodstuffs including cereals, nuts, spices and dried fruits. Mycotoxins are produced by several fungi in foodstuffs and these feed during production, storage and transportation, often under warm and humid conditions. Mycotoxins of most concern from a food safety perspective include the aflatoxins, ochratoxin A, fumonisins, trichothecenes and zearalenone.

Aflatoxins are most commonly found in maize and peanuts, and feed as contaminants, and these can also be found in the milk of animals that are fed aflatoxin-contaminated feed in the form of aflatoxin M1.

Most natural toxins found in fish are produced by species (spp.) of naturally occurring marine algae. They accumulate in fish when they feed on the algae or on other fish that have fed on the algae. Ciguatera fish poisoning is associated with consumption of toxin-contaminated subtropical and tropical reef fish. Unfortunately,

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these toxins are not destroyed by normal cooking or processing. Naturally occurring cyanogenic glycosides are found in raw or unprocessed cassava (Manihot esculenta), which can cause nerve damage or death if consumed in quantity.

Food poisoning from the consumption of poisonous wild mushrooms has been reported frequently during the monsoon season in countries of the South-East Asia Region. In some episodes, whole families have lost their lives due to consumption of poisonous wild mushrooms. The majority of fatal mushroom poisoning occurs due to ingestion of Amanita phalloides – the death cap – due to its high content of Amatoxin, a potent cytotoxin. Fatal poisoning is usually associated with delayed onset of symptoms, which are very severe and have a toxic effect on the liver, kidney and nervous system.

Unfortunately, cases remain undiagnosed, under-reported and unpublished as these happen in rural communities.

Food allergy

Food allergy is an abnormal response to a food triggered by the body’s immune system.

Individuals with food allergies develop symptoms by eating foods that for the vast majority of the population are part of a healthy diet. Food allergy is a growing problem.

The prevalence of food allergies in the general population has been roughly estimated to be around 1–3% in adults and 4–6% in children.

Peanut or groundnut allergy occurs early in life (<five years of age) and is believed to be lifelong. Egg and milk allergies are most common food allergies among infants but are often outgrown. More than 70 foods have been described as causing food allergies.

Several studies indicate that 75% of allergic reactions among children are due to a limited number of foods, namely egg, peanuts, milk, fish and nuts. Fruits, vegetables, nuts and peanuts are responsible for most allergic reactions among adults.

Food allergies are a concern for both the allergic individual and also all involved in supplying and preparing food, including family and friends, caterers, restaurants and the food industry. There is no cure for food allergies, so it is important to avoid the food that cause the allergy. Having the correct information to eat, order food and shop wisely can make a big difference. People with food allergies have to be extremely careful about what they eat. Eating away from home is often risky for an allergic person.

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Global burden of foodborne diseases

Foodborne diseases (FBDs) are an important cause of illness and death around the world. However, the extent and cost of unsafe food, and especially the burden due to chemical and parasitic contaminants in food, is still not fully known. Epidemiological data on FBDs and laboratory capacity to detect the cause of FBDs are not available widely, particularly in the developing world. As a result, many foodborne outbreaks often go unrecognized, unreported or uninvestigated.

A major problem in addressing food safety concerns is the lack of accurate data/

information regarding the extent and cost of FBDs. Lack of comprehensive data and information on the burden of FBDs makes it challenging for policy-makers to set public health priorities and allocate resources. Therefore, the World Health Organization (WHO) has taken an initiative to carry out an estimation of the global burden of FBDs and generation of evidence-based data and information that will enable policy-makers to prioritize and allocate resources for food safety.

Objectives

WHO Department of Food Safety, Zoonoses and Foodborne Diseases together with its partners launched the initiative to estimate the global burden of FBDs in 2006.

The primary goal of the initiative is to enable policy-makers and other stakeholders to set appropriate, evidence-based priorities in the area of food safety. After an initial consultation, WHO established a Foodborne Disease Burden Epidemiology Reference Group (FERG) in 2007 to lead the initiative. These objectives were to:

• strengthen the capacity of Member States to conduct the burden of foodborne disease assessments and to increase the number of Member States that have undertaken a burden of foodborne disease study;

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• provide estimates on the global burden of FBDs according to age, sex and regions for a defined list of causative agents of microbial, parasitic and chemical origin;

• increase awareness and commitment among Member States for the implementation of food safety standards; and

• encourage Member States to use burden of foodborne disease estimates for cost-effective analyses of prevention, intervention and control measures.

Methodology

These objectives were addressed through the establishment of six task forces, each pursuing on groups of hazards or select aspects of the methodology. Together with the WHO Secretariat, these task forces commissioned systematic reviews and other studies to provide the data from which burden estimates could be calculated.

According to WHO, it was important to provide estimates of foodborne disease at as localized a level as possible because not all foodborne hazards affect every country equally. On account of gaps in the information available from certain countries (especially developing countries), subregional estimates are considered more robust as they build on the data from several countries in each Region.

The six WHO regions were divided into 14 subregions as shown in Figure 1, based on five categories considering child and adult mortality rates, as follows:

• Category A: very low child and adult mortality

• Category B: low child mortality and very low adult mortality

• Category C: low child mortality and high adult mortality

• Category D: high child and adult mortality

• Category E: high child mortality and very high adult mortality

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Figure 1: Categorization of subgroups under WHO regions for estimation of global burden of foodborne diseases

Source: FERG Report (2015)

The list of countries that were divided into 14 subregions is available in Annex 3. A country can obtain national estimates by referring to estimates for the subregion to which it belong.

In addition to providing global and regional estimates, the initiative also sought to promote actions at a national level. This involved capacity-building through national foodborne disease burden studies, and encouraging the use of information on the burden of disease in setting evidence-informed policies. A suite of tools and resources were created to facilitate national studies on the burden of foodborne diseases and pilot studies were conducted in four countries (Albania, Japan, Thailand and Uganda).

Thirty-one foodborne hazards causing 32 diseases with 11 diarrhoeal disease agents (1 virus, 7 bacteria and 3 protozoa), 7 invasive infectious disease agents (1 virus, 5 bacteria and 1 protozoa), 10 helminths and 3 chemicals are included (as shown in Table 1).

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Table 1: Hazards and foodborne diseases considered in studies

Hazards Foodborne diseases

Diarrhoeal disease agents

Virus (1) Norovirus

Bacteria (7) Campylobacter sp., Enteropathogenic E.

coli (EPEC), Enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli, Non-typhoidal Salmonella enterica, Shigella sp., Vibrio cholerae (V. cholerae)

Protozoa (3) Cryptosporidium sp., Entamoeba histolytica, Giardia sp.

Invasive infectious disease agents

Virus (1) Hepatitis virus A (HAV)

Bacteria (5) Brucella sp., Listeria monocytogenes,

Mycobacterium bovis (M. bovis), Salmonella paratyphi A (S. paratyphi A), Salmonella typhi (S. typhi)

Protozoan (1) Toxoplasma gondii

Helminths Cestodes (3) Echinococcus granulosus, Echinococcus

multilocularis, Taenia solium (T.solium) Nematodes (2) Ascaris sp., Trichinella sp.

Trematodes (5) Clonorchis sinensis, Fasciola sp., Opisthorchis sp., Paragonimus sp., intestinal fluke

Chemicals Toxins and poisons (3) Aflatoxin, Cassava cyanide, Dioxin

Together, the 31 hazards caused an estimated 600 million foodborne illnesses, 420 000 deaths and 33 million disability-adjusted life-years (DALY) in 2010. DALY is a measure of the overall disease burden expressed as the number of years lost due to ill-health, disability or early death.

Diarrhoeal diseases are the leading cause of foodborne disease illnesses – particularly norovirus and Campylobacter spp.. It is estimated that one in 10 people in the world fall ill every year due to eating contaminated food, as shown in Figure 2.

Foodborne diarrhoeal disease agents caused 230 000 deaths, particularly non-typhoidal S. enterica (NTS), which causes diarrhoeal and invasive disease. Other major causes of foodborne deaths were S. typhi, T. solium, hepatitis A virus and aflatoxin.

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Figure 2: Burden of foodborne illness

1 in 10 people in the world fall ill every year due to eating contaminated food

The global burden of FBDs is considerable with marked regional variations. The burden of FBDs is borne by individuals of all ages, but particularly children under five years of age and persons living in low-income regions of the world. Nearly 40% of the foodborne disease burden was among children under five years of age with 18 million DALY lost due to foodborne diarrhoeal disease agents, particularly NTS and EPEC.

Other foodborne hazards with a substantial contribution to the global burden included S. typhi and T. solium.

Gaps and limitations

Estimates are based on the best available data at the time of reporting. Identified data gaps were filled using imputation, assumptions and other methods.

Data gaps were a major hurdle to making estimates of the foodborne disease burden in these national studies. The global and regional estimates provided by FERG offer an interim solution until improved surveillance and laboratory capacity is developed.

It is likely that the true number of illnesses and deaths resulting from FBDs worldwide is even higher because:

• many cases of food poisoning go unrecognized and untreated,

• there are gaps in the collection and reporting of data (especially in developing countries) on the burden of FBDs,

• there are other causes beyond the 31 hazards included in this report, especially in the chemical domain,

• for certain foodborne hazards, there is still considerable uncertainty regarding their clinical impact. Current estimates only included symptoms for which sufficient evidence existed.

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WHO is focusing its efforts on supporting national policy-makers and governments in improving surveillance of FBDs to obtain a clearer picture of the unique local challenges and implement the right strategies to prevent, detect and manage foodborne risks.

The report prepared by the WHO Foodborne Disease Burden Epidemiology Reference Group provides the first estimates of global foodborne disease in terms of incidence, mortality and disease burden in the form of DALY. This report is the outcome of 10 years of monumental work by WHO and its donors and partners as well as a number of individuals contributing to this initiative from around the world. The report is an essential part of WHO’s efforts to facilitate global prevention, detection and response to public health threats associated with unsafe food. It is a continuation of WHO activities dedicated to driving food safety as highlighted during World Health Day 2015.

An important goal of the FERG initiative and the next step in the process is to encourage and support countries in undertaking foodborne burden of disease studies, using consistent WHO tools and processes. Therefore, a guide to national burden of foodborne diseases study has been briefly mentioned in Annex 2.

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Foodborne diseases in the WHO South-East Asia Region

Home to a quarter of the world’s population, the WHO South-East Asia Region has the second highest burden of FBDs per population among WHO regions. It has more than half of the global infections and deaths due to typhoid fever or hepatitis A.

Based on data (2010) from the FERG report, the annual burden of FBDs in the South-East Asia Region includes more than:

• 150 million illnesses

• 175 000 deaths

• 12 million DALYs.

Figure 3: Top 10 causes of foodborne illnesses in the WHO South-East Asia Region

0 5 million 10 million 15 million 20 million 25 million Salmonella typhi

Ascaris species Entamoeba histolytica Hepatitis A virus Enteropathogenic E. coli Norovirus Non-typhoidal S. enterica Enterotoxigenic E. coli Shigella species Campylobacter species

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As shown in Figure 3, Campylobacter sp. was the leading cause of foodborne illness with an estimated more than 20 million cases every year in the Region. This was followed by Shigella sp. and enterotoxigenic Escherichia coli with more than 19 million cases each. At the fourth spot, NTS was estimated to cause more than 16 million infections.

In aggregate terms, E. coli and S. spp. were the leading causes of foodborne illnesses. Norovirus and hepatitis A virus also caused significant diseases in the Region.

Amoebiasis caused by Entamoeba histolytica and worm infestation by Ascaris sp. were the leading parasitic causes of illness due to contaminated food.

Figure 4: Top 10 causes of deaths due to foodborne illnesses in the WHO South-East Asia Region

0 5 000 10 000 15 000 20 000 25 000 30 000 35 000

Campylobacter spp.

Taenia solium Salmonella paratyphi A Vibrio cholerae Enterotoxigenic E. coli Enteropathogenic E. coli Non-typhoidal S. enterica Hepatitis A virus Norovirus Salmonella typhi

As shown in Figure 4, the leading cause of death due to foodborne diseases in the Region was S. typhi (more than 32 000 deaths), followed by norovirus (nearly 19 000 deaths) and hepatitis A virus (nearly 18 000 deaths) respectively. NTS at fourth position was responsible for nearly 16 000 deaths in the Region. EPEC and ETEC caused more than 15 000 and 10 000 deaths respectively. Cholera (caused by V. cholerae) and paratyphoid fever (caused by S. paratyphi A) were estimated to have caused more than 7600 and nearly 7500 deaths respectively.

Among the parasites, the pork tapeworm (T. solium) was estimated to cause more than 6800 deaths annually. Despite being the leading cause of foodborne illness in the

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Going by the estimated burden of FBDs in terms of DALYs in the Region as shown in Figure 5, S. typhi is the leading cause of ill-health, disability or early death and leads to the highest number of DALYs (nearly 2.3 million). S. paratyphi A that causes a similar illness was also estimated to be responsible for more than half a million DALYs every year.

Figure 5: Top 10 causes of DALYs due to foodborne illnesses in the WHO South-East Asia Region

0 0.5 million 1 million 1.5 million 2 million 2.5 million Salmonella paratyphi A

Vibrio cholerae Campylobacter spp.

Taenia solium Enterotoxigenic E. coli Hepatitis A virus Non-typhoidal S. enterica Enteropathogenic E. coli Norovirus Salmonella typhi

Viral causes of foodborne diseases – norovirus and hepatitis A virus were estimated to be responsible for nearly 1.3 million and 870 000 DALYs every year.

Interestingly, non-typhoidal S. enterica continued to occupy the fourth position among the top 10 causes of DALYs and was estimated to be responsible for more than a million DALYs. EPEC and ETEC were responsible for nearly 1.2 million and 760 000 DALYs respectively.

The pork tapeworm was responsible for nearly 670 000 DALY and Campylobacter sp. and cholera led to 600 000 and 530 000 DALY respectively.

Foodborne diseases in under-five children

The burden of FBDs in children under five years of age is quite high in the Region as compared with other WHO regions. As shown in Figure 6, three out of 10 children suffer from diarrhoea in South-East Asia.

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Figure 6: Under-five children suffering from diarrhoea in the WHO South-East Asia Region

3 in 10 children under five years of age suffer from diarrhoea

The Region contributes to one third of the global deaths due to diarrhoea in children under five years of age that could be prevented.

Figure 7: Top 10 causes of foodborne illnesses in children under five years of age in the South-East Asia Region

0 2 million 4 million 6 million 8 million 10 million 12 million Entamoeba histolytica

Hepatitis A virus Giardia spp.

Ascaris spp.

Non-typhoidal S. enterica Norovirus Shigella spp.

Campylobacter spp.

Enteropathogenic E. coli Enterotoxigenic E. coli

In children under five years of age (as shown in Figure 7), the top three causes of foodborne illnesses were ETEC (nearly 11 million cases), EPEC (nearly 7.3 million cases) and Campylobacter sp. (nearly 7 million cases).

Shigella sp., norovirus and NTS caused 5.2, 5 and 4.4 million illnesses respectively and hepatitis A virus caused nearly 1.4 million cases in children under five years of age.

Among parasitic infections in under-five children, round worm (Ascaris sp.),

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Figure 8: Top 10 causes of deaths due to foodborne illnesses in children under five years of age in the South-East Asia Region

0 1 000 2 000 3 000 4 000 5 000 6 000 7 000 8 000

Taenia solium Salmonella paratyphi A Shigella spp.

Hepatitis A virus Campylobacter spp.

Enterotoxigenic E. coli Non-typhoidal S. enterica Norovirus Salmonella typhi Enteropathogenic E. coli

Source: FERG report (2015)

As shown in Figure 8, the top three causes of death due to FBDs in children under five years of age in the Region were EPEC (nearly 7400), S. typhi (6600) and norovirus (4000).

Other major causes of death in children under five years of age were estimated to be NTS (3663 deaths), ETEC (3532 deaths), Campylobacter spp. (3322 deaths) and hepatitis A virus (2805 deaths).

Figure 9: Top 10 causes of DALYs due to foodborne illnesses in children under five years of age in the South-East Asia Region

0 100 000 200 000 300 000 400 000 500 000 600 000 700 000 800 000 Ascaris spp.

Dioxin Shigella spp.

Hepatitis A virus Campylobacter spp.

Enterotoxigenic E. coli Non-typhoidal S. enterica Norovirus Salmonella typhi Enteropathogenic E. coli

Source: FERG report (2015)

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In terms of DALY due to FBDs in children under five years of age (as shown in Figure 9), the leading cause was EPEC (nearly 674 000 DALY), followed by S. typhi (610 000 DALY) and norovirus (nearly 364 000 DALY).

Other causes of DALYs include NTS, ETEC, Campylobacter sp. hepatitis A virus, Shigella sp. and dioxin. Interestingly, dioxin was estimated to have a significant impact in children under five years of age in the Region with more than 160 000 DALYs. It was based on the result of breast milk testing for a persistent organic pollutants (POPs) study carried out in India under the Global Environmental Monitoring System (GEMS).

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Conclusions and action points

The most comprehensive report to date on the impact of contaminated food on health and well-being is titled ‘Estimates of the Global Burden of Foodborne Diseases’. These estimates are the result of a decade of work, including inputs from more than 100 experts from around the world. Based on what we know now, it is apparent that the global burden of FBDs is considerable. The FERG report highlights the global threat posed by FBDs in the context of globalization of the food trade. Unsafe food endangers everyone and billions of people are at risk.

The global burden of FBDs is considerable with marked regional variations. The burden of FBDs is borne by individuals of all ages, and particularly children under five years of age and persons living in low-income regions of the world. These estimates are conservative; further studies are needed to address the data gaps and limitations of this study. The considerable difference in the burden of foodborne disease between low- and high-income regions suggests that a major proportion of the current burden is avoidable and that control methods do exist.

The report highlights that action to reduce illnesses and deaths from FBDs must be tailored according to regional and national needs as the types of contaminants and reasons for their prevalence differ across the world. The report will support policy- makers in implementing the right strategies to prevent, detect and manage foodborne risks to improve food safety.

The report will enable governments achieve the Sustainable Development Goal 2 for food security and nutrition (target 2.1: “By 2030, end hunger and ensure access by all people, in particular the poor and people in vulnerable situations, including infants, to safe, nutritious and sufficient food all year round”). The achievement of Goal 3 (Ensure healthy lives and promote well-being for all at all ages); Goal 1 (End Poverty in all its forms everywhere) and Goal 8 (Promote sustained, inclusive and sustainable

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economic growth, full and productive employment and decent work for all) will also be cited through promoting the safety of food supply domestically and internationally.

The report also reinforces the need for governments, the food industry and individuals to do more to make food safe and prevent foodborne illnesses and intoxications. Safe drinking water, good hygienic practices and improved sanitation are keys for preventing foodborne illnesses and intoxications.

The majority of FBDs and deaths are preventable. Food safety is a public health priority and governments should develop policies and regulatory frameworks to establish and implement effective food safety systems. Food safety systems should ensure that food producers and suppliers along the whole food chain operate responsibly and supply safe food to consumers.

Food safety is a shared responsibility. All food operators and consumers should understand the roles they must play to protect their health and that of the wider community. All stakeholders can contribute to improvements in food safety throughout the food chain by incorporating these estimates into policy development at the national and international levels.

Think globally, act locally: while there is no single, global solution to the problem of FBDs, a strengthened food safety system in one country will positively impact the safety of food in other countries. There is need for coordinated, cross-border action across the entire food supply chain.

Coordinated action at the global, regional and national levels is needed to address risks of FBDs and ensure food safety. Education and training are needed on prevention of FBDs among food producers, suppliers, handlers and the general public, including women and school children.

Key action points towards ensuring food safety in the Region include the conduct of national studies on the burden of FBDs, strengthening of laboratory capacity to be able to detect FBDs, and strengthening the surveillance of FBDs, including the collation of local data to validate regional estimates and translation of estimates of FBDs into food safety policy.

The International Health Regulations (IHR 2005) is a legally binding instrument to

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2015 clearly illustrates that most Member States have limited capacity for surveillance, assessment and management of priority food safety events. Therefore, the WHO Regional Office for South-East Asia is providing technical support to Member States to evaluate existing national foodborne disease surveillance systems, including risk assessment and the management of food safety events, and to identify action plans to improve surveillance, assessment and management of priority FBDs and food safety events.

WHO is working with governments and partners to reduce the level of food contamination throughout different stages of the food-chain. These stages include the point of final consumption to the levels at which the exposure to pathogens and contaminants does not pose significant risks for human health.

WHO promotes the use of international platforms such as the joint WHO-FAO (Food and Agriculture Organization of the United Nations) International Food Safety Authorities Network (INFOSAN) to ensure effective and rapid communication during food safety emergencies. WHO also works closely with other international organizations to ensure food safety along the entire food-chain, from production to consumption, in line with the Codex Alimentarius (CA). CA is a collection of international food standards, guidelines and codes of practice covering all main foods and steps in the food supply chain.

FBDs are preventable. WHO is promoting the important role that everyone can play to promote food safety through systematic disease prevention and awareness programmes. WHO’s Five Keys to Safer Food explains the basic principles that each individual should know all over the world to prevent FBDs:

(1) Keep clean

– thoroughly wash raw fruits and vegetables with tap water.

– keep clean hands, kitchen and chopping board all the time.

(2) Separate raw and cooked food

– do not mix raw food and ready-to-eat food.

– do not mix raw meat, fish and raw vegetables.

(3) Cook thoroughly

– thoroughly cook all meat, poultry and seafood, especially shellfish.

– reheat all leftovers until they are steaming hot.

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(4) Keep food at safe temperatures

– refrigerate cooked food within two hours of preparation.

– never defrost food at room temperature; defrost frozen food in the refrigerator, cold water or the microwave.

(5) Use safe water and raw materials

– use safe drinking water for food preparation.

– check use-by dates and labels while buying packed food.

(29)

Annex 1 Classification of foodborne diseases

1 DiseaseEtiologic agent or causeIncubation period (latency) Signs and symptoms

Food implicated

Specimens to be obtained

Contributing factors 1. Initial or major signs and symptoms of the upper digestive tracts (nausea, vomiting) 1.1 Incubation period tends to be less than 1 hour Fungal agents Poisoning by mushrooms of the group that causes gastrointestinal irritation

Possibly resin-type substances found in some types of mushrooms From 30 minutes to 2 hours Nausea, vomiting, retching, diarrhoea, abdominal pains Many varieties of wild mushrooms

Vomit

Ingestion of unknown toxic varieties of mushrooms, through confusion with other edible varieties

Chemical agents Antimony poisoning Antimony in enamelled iron utensils From a few minutes to 1 hour Vomiting, abdominal pains, diarrhoea Very acid food and beverages Vomit, stool and urine Use of utensils that contain antimony

,

storage of very acid food in enamelled iron utensils

Cadmium poisoning

Cadmium in plated utensils From 15 to 30 minutes

Nausea, vomiting,

abdominal pains, diarrhoea, shock Very acid foods and drinks, candies and other cake decorations Vomit, stool, urine and blood

Use of utensils that contain cadmium, storage of very acid food in containers that contain cadmium, ingestion of foods that contain cadmium

2 1 Adapted and modified from Instituto Panamericano de Protección de Alimentos y Zoonosis (INPPAZ) – Pan American Health Organization WHO 2 Samples should be collected from any of the listed foods that have been ingested during the incubation period of the disease.

(30)

Etiologic agent or causeIncubation period (latency) Signs and symptoms

Food implicated

Contributing factors

Copper in pipes and utensils From a few minutes to a few hours Metallic taste, nausea, vomiting (green vomit), abdominal pains, diarrhoea Very acid food and beverages Vomit, gastric lavage, urine and blood

Storage of very acid food in copper utensils or use of copper tubing in serving very acid beverages, defective valves on devices to prevent reflux (in dispensers)

Sodium fluoride in insecticides From a few minutes to 2 hours Salty or soapy taste, numbness in the mouth, vomiting

, diarrhoea,

abdominal pains, pallour

, cyanosis,

dilated pupils, spasms, collapse, shock Any accidentally contaminated food, particularly dry food such as powdered milk, flour

, baking

powder and cake mixes Vomit and gastric lavages

Storage of insecticides in the same place as food, confusion of pesticides with powdered foods

Lead contained in earthenware pots, pesticides, paints, plaster and putty 30 minutes or more

Metallic taste, burning in the mouth, abdominal pains, milky vomit, black stool or presence of blood, bad breath, shock, blue line at the edge of gums ("lead line") Very acid food and beverages stored in vessels containing lead, any accidentally contaminated food Vomit, gastric lavages, stool, blood and urine Use of vessels containing lead, storage of very acid food in vessels containing lead, storage of pesticides in the same place as food

Tin in tin cans

From 30 minutes to 2 hours Swelling, nausea, vomiting, abdominal

pains, diarrhoea, headache Very acid foods and beverages Vomiting, stool, urine and blood Storage of acid foods in unlined tin containers

Zinc in galvanized containers From a few minutes to 2 hours Mouth and abdominal pains, nausea, vomiting

, dizziness

Very acid food and beverages Vomit, gastric lavages, urine, blood and stool Storage of very acid food in galvanized tins

(31)

DiseaseEtiologic agent or causeIncubation period (latency) Signs and symptoms

Food implicated

Contributing factors 1.2 Incubation period of 1 to 6 hours Bacterial agents Bacillus cereus gastroenteritis (type emetic)

Exoenterotoxin of B. cereus

From ½ to 5 hoursNausea, vomiting,

occasionally diarrhoea Cooked or fried rice and plates of rice with meat

Vomit and stool

Storage of cooked food at warm temperatures, food cooked in large containers, food prepared several hours before serving

Staphylococcal food poisoning Exoenterotoxins A, B

, C, D and E of Staphylococcus aureus.

Staphylococci from the nose, skin, and lesions of infected people and animals, and infected udders of cows From 1 to 8 hours, average of 2 to 4 hours

Nausea, vomiting, retching, abdominal pains, diarrhoea, prostration Ham, beef or poultry products, cream-filled pastries, food mixes and leftover food Patient: vomit, stool, rectal swab. Carrier: nasal swabs, swabs from lesion, and rectal swabs Inadequate refrigeration, handler touched cooked food, preparation of food several hours before serving

,

handlers with purulent infections, food kept at warm temperatures (bacterial incubation), fermentation of foods abnormally low in acids

Chemical agents 3 Nitrite poisoning

Nitrites or nitrates used as compounds to cure meat, or water from shallow wells

From 1 to 2 hoursNausea, vomiting,

cyanosis, headache, dizziness, weakness, loss of consciousness, chocolate

-coloured blood

Cured meats, any accidentally contaminated food and exposure to excessive nitrification

BloodUse of excessive quantities

of nitrites or nitrates to cure food or conceal spoilage, confusion of nitrites with common salt, and other condiments, inadequate refrigeration, excessive nitrification in fertilized food

3 Carbon monoxide poisoning can resemble some of the diseases included in this category. Patients who have been inside a closed automobile with the motor running or who have been in heated rooms with poor ventilation are at risk of exposure to carbon monoxide.

(32)

Food implicated

Okadaico acid and other toxins produced by dinoflagellates of the

Dinophysis spp.

From 1/2 to 12 hours, usually 4 hours Diarrhoea, nausea, abdominal pains Mussels, clams, oysters

Gastric rinse

Shellfish caught in water with high concentration of Dynophysis spp.

Cyclopeptides and gyromitrine found in certain mushrooms From 6 to 24 hours Abdominal pains, feeling of fullness, vomiting

, prolonged

diarrhoea, loss of strength, thirst, muscle cramps, rapid and weak pulse, collapse, jaundice, somnolence, dilated pupils, coma, death Amanita phalloides, A. verna, Galerina autumnalis. Esculenta giromitra (false colmenilla) and similar spp. of mushrooms

Urine, blood, vomit Ingestion of certain spp. of

Amanita, Galerina and Giromitra

mushrooms, ingestion of unknown varieties of mushrooms, confusion of toxic mushrooms with edible varieties

-like

Norovirus viruses are relatively stable in the environment and can survive freezing and heating to 60°C

12 to 48 hoursVomiting, watery,

non-bloody diarrhoea with abdominal cramps, low

-grade fever,

myalgia, malaise, headache Contaminated food or water

Stool specimens taken within 48 to 72 hours after onset of symptoms

Direct person-to-person

spread or faecally contaminated food or water

, touching surfaces

or objects contaminated with norovirus, noroviruses can also spread via a droplet route from vomitus.

(33)

Food implicated

Small round viruses, productive of gastroenteritis Includes adenovirus, coronavirus, rotavirus, parvovirus, and astrovirus

½ to 3 days, usually 36 hours

Nausea, vomiting,

diarrhoea, abdominal pain, myalgia, headache, light fever . Duration: 36 hours Shellfish from contaminated water

Stool, blood in acute and convalescent phases

Infected people who touch food ready for consumption, harvest of shellfish from contaminated waters, improper disposal of wastes, use of contaminated water

2. Manifestation of pharyngitis and respiratory signs and symptoms 2.1 Incubation period less than 1 hour Chemical agents Calcium chloride poisoning Freezing mixtures of calcium chloride for freezing desserts

A few minutes

Burning in the tongue, mouth, and throat, vomiting

Frozen dessertsVomit

Contamination of popsicles during freezing

, permitting the

introduction of calcium chloride in the syrup

Sodium hydroxide poisoning

Sodium hydroxide (caustic soda) in compounds used to wash bottles, detergent, drain cleaners, hair

- relaxants

A few minutes

Burning of the lips, mouth and throat; vomiting , abdominal pains, diarrhoea

Bottled beveragesVomit

Improper rinsing of bottles washed with caustic substances

2.2 Incubation period from 18 to 72 hours Bacterial agents Infections by beta- haemolytic streptococci Streptococcus pyogenes

of the

throat and lesions of infected people From 1 to 3 daysPharyngitis, fever, nausea, vomiting,

rhinorrhoea, sometimes rash Raw milk, foods containing egg Pharyngeal swabs, vomitWorkers who touched

cooked food, workers with purulent infections, inadequate refrigeration, improper cooking or reheating

, preparation

of food several hours before serving

(34)

Food implicated

Contributing factors Coxiella burnetii

2-3 weeks (3-30 days) Chills, headache, malaise, myalgia and sweets Raw milk from infected cattle or goats, direct contact with contaminated materials

Serum

Consumption of raw milk, direct contact with aborted materials, inadequate disinfection and disposal of aborted materials

Exoenterotoxin of B. cereus, organisms in the soil From 8 to 16 hours (average of 12 hours) Nausea, abdominal pains, diarrhoea

Foods made from grains, rice, custard, sauces, meatballs, sausages, cooked vegetables, dehydrated or reconstituted products

StoolInadequate refrigeration,

storage of food at warm temperatures (bacterial incubation), preparation of food several hours before serving , improper reheating of leftovers

Endoenterotoxin formed during the sporulation of C. perfringens in the

intestines, the body

, in human or

animals faeces or in the soil From 8 to 22 hours (average of 10 hours)

Abdominal pains, diarrhoea Cooked beef or poultry

, broths, sauces and soups

Stool

Inadequate refrigeration, storage of food at warm temperatures (bacterial incubation), preparation of food several hours before serving

, improper

reheating of leftover food

(35)

Food implicated

Contributing factors 3.2 Incubation period usually from 18 to 72 hours Bacterial agents Diarrheal diseases caused by Aeromonas

Aeromonas hydrophila

1 to 2 daysWatery diarrhoea,

abdominal pain, nausea, headache Fish, shellfish, snails, water

Stool

Contamination of food in sea or surface water

Campylobacter InfectionCampylobacter jejuni 2 to 7 days usually between 3 and 5 Abdominal pains, diarrhoea (frequently with mucus and blood), headache, myalgia, fever

,

anorexia, nausea, vomiting

. Sequellae:

Guillian-Barre syndrome Raw milk, beef liver

, raw clams

Stool or rectal swabs, blood Drinking raw milk, handling raw products, eating raw or undercooked poultry

,

inadequate cooking or pasteurization, cross

-

contamination with raw meat

Cholera

Endoenterotoxin of V. cholerae classical and El Tor biotypes,

from faeces of infected persons

From 1 to 3 days

Severe, watery diarrhoea (rice water stools), vomiting

,

abdominal pains, dehydration, thirst, collapse, loss of skin tone, shrivelled fingers, sunken eyes Raw fish and shellfish, food washed or prepared with contaminated water

, water

Stool

Harvesting of fish and shellfish from water contaminated with sewage in endemic areas, poor personal hygiene, infected handlers who touched food, inadequate cooking

, use of

contaminated water in washing or rinsing food, improper disposal of wastewater , use of waste from latrines as fertilizer

(36)

Food implicated

Contributing factors caused vibrioCholera like vibrio

From 5 to 48 hours, average from 10 to 24 hours Abdominal pains, diarrhoea, nausea, vomiting

, fever,

chills, headache, myalgia Various foods, water Stool, rectal swabs Infected handlers who touch food, insufficient cooling

, incomplete cooking, improper cleaning and disinfection of equipment

E. coli O157:H7,

O26, O111, O115, O113 1 to 10 days usually 2 to 5 days

Watery diarrhoea

followed by bloody diarrhoea, severe abdominal pain, blood in the urine. Sequelae: Haemolytic uremic syndrome (HUS)

Hamburger, raw

milk, sausages, yogurt, lettuce, water Stool, rectal swabs Hamburger made from meat of infected animals, consumption of raw meat and milk, inadequate cooking

, cross-contamination,

infected people touching food ready for consumption, improper desiccation and fermentation of meats

Strains of Enteroinvasive E. coli

½ to 3 days

Severe abdominal pain, fever

, watery

diarrhoea, (usually with mucus and blood present) tenesmus Salads and other food that are not subsequently treated, water Stool, rectal swabs

Inadequate cooking,

infected persons touching food ready for consumption, not washing hands after defecation, storing food at room temperature, storing food in the refrigerator in large containers, preparing food several hours before serving , improper reheating of food

(37)

Food implicated

Diarrhoea caused by ETEC

Strains of ETEC½ to 3 days

Profuse watery diarrhoea (without mucus or blood) abdominal pain, vomiting

,

prostration, dehydration, light fever Salads and other food that are not subsequently thermally treated, fresh cheeses, water Stool, rectal swabs

Inadequate cooking,

infected people touching food ready for consumption, not washing hands after defecation, storage of food at room temperature, keeping food in the refrigerator in large containers, preparing food several hours before serving

,

improper reheating of food, use of raw milk in making cheese

Enteritis by Plesiomonas

Pleisomonas shigeloides

1 to 2 days

Diarrhoea with mucus and blood in the stool

Water

Stool, rectal swabs

Inadequate cooking Salmonellosis

Various serotypes of Salmonella from faeces of infected people and animals From 6 to 72 hours, average from 18 to 36 hours Abdominal pains, diarrhoea, chills, fever

, nausea, vomiting, malaise Beef and poultry and their byproducts, egg products, other foods contaminated with salmonellae Stool, rectal swabs

Inadequate refrigeration, storage of food at warm temperatures (bacterial incubation), inadequate cooking and reheating

, preparation

of food several hours before serving

, cross-

contamination, improper cleaning of equipment, infected handlers who touch cooked food, acquisition of food from contaminated sources.

(38)

Food implicated

Contributing factors Shigella flexneri,

S. dysenteriae, S. sonnei

and S. boydii

From ½ to 7 days, usually from 1 to 3 days Abdominal pains, diarrhoea, mucoid faeces with blood present, fever Any food ready for consumption that becomes contaminated, frequently salads, water Stool, rectal swabs

Infected handlers touching the food, inadequate refrigeration, improper cooking and reheating

V. parahaemolyticus from sea water or marine products

From 2 to 48 hours, average 12 hours Abdominal pains, diarrhoea, nausea, vomiting

, fever, chills, headache Raw or contaminated sea food, shellfish Stool, rectal swabs

Inadequate cooking,

inadequate refrigeration, cross

-contamination,

improper cleaning of equipment, use of sea water in preparing food

Yersinia enterocolitica

1 to 7 days

Abdominal pains (can simulate appendicitis), light fever

, headache,

discomfort, anorexia, nausea, vomiting

Raw milk, water

Stool, rectal swabs Inadequate cooking or pasteurization, cross

-contamination,

contaminated ingredients or water

Enteric viruses (echovirus, coxsackievirus, reovirus, adenovirus) From 3 to 5 daysDiarrhoea, fever, vomiting, abdominal

pains, sometimes respiratory symptoms Food ready for consumption

Stool

Poor personal hygiene, infected workers touching food, improper cooking and reheating

Ascaris lumbricoides14 to 20 days

Stomach disorders, cramps, vomiting

, fever

Vegetables and water

Stool

Inadequate waste disposal, poor hygiene in food handling

(39)

Food implicated

Amoebic dysentery (amoebiasis) Entamoeba histolytica From a few days to several months usually between 2 and 4 weeks Abdominal pains, constipation or diarrhoea with blood and mucus Vegetables and raw fruits

Stool

Poor personal hygiene, infected handlers touching the food, improper cooking and reheating

Giardiasis

Giardia lamblia from faeces of infected people

From 1 to 6 weeks

Abdominal pains, diarrhoea with mucus, fatty stools Raw fruits and vegetables, water

Stool

Poor personal hygiene, infected handlers touching food, improper cooking

, improper waste water disposal CryptosporidiosisCryptosporidium parvum

1 to 12 days, usually 7 days Profuse watery diarrhoea, abdominal pain, anorexia, vomiting

, light fever

Apple cider, water

Stool, intestinal biopsy

Improper disposal of animal wastes, contamination from the animal environment, inadequate filtering of water

Hydatidosis (unilocular or multilocular) Echinococcus granulosus

,

Echinococcus multilocularis

Months to years

Abdominal pain, abnormal abdominal tenderness, hepatomegaly with an abdominal mass, jaundice, fever Food or water contaminated with faeces of infected dog

, fox

Biopsy or serum

Consumption of raw vegetables or water contaminated with faeces of infected dog or fox

Liverfluke (Fascioliasis)Fasciola hepaticaFrom 4 to 6 weeksDyspepsia, fever,

right upper quadrant pain, anorexia, hepatomegaly

, splenomegaly,

ascites, urticaria, respiratory symptoms, and jaundice Aquatic plants or plants with high moisture content

Stool, tissue biopsy Eating raw aquatic plants, inefficient disposal of human and animal wastes in pond or water bodies

foodborne diseases

in the South-East Asia Region

foodborne diseases

Burden of

Burden of foodborne diseases

in the South-East Asia Region

Contents

Acronyms

Introduction: Foodborne diseases

Foodborne infections

Chemicals and toxins in food

Food allergy

Global burden of foodborne diseases

Objectives

Methodology

Gaps and limitations

Foodborne diseases in the WHO South-East Asia Region

Foodborne diseases in under-five children

Conclusions and action points

Annex 1 Classification of foodborne diseases