Food Protection Trends - August 2010 - 484

INTRODUCTION
Foodborne illnesses are prevalent in all parts of the world, and their toll on human health is enormous. They affect consumers and industries all over the world, in developed as well as developing countries; some industrialized countries have estimated that each year up to 30% of their population may become ill from biological hazards in the food supply (14). The World Health Organization (WHO) has identified many different types of food contaminants as major sources of disease, including Salmonella, Campylobacter, Clostridium, hepatitis A, Cholera, Listeria, enterohemorrhagic E. coli, metals, persistent organic pollutants, biologically derived toxins, pesticides, toxic chemicals and organisms causing transmissible spongiform encephalopathies (TSE)-type diseases (e.g., bovine spongiform encephalopathy) (15). Some countries publish comprehensive estimates of their national burden of disease linked to foodborne pathogens, while others do not. For example, in the United States, the Centers for Disease Control and Prevention (CDC) estimated in 1999 that foodborne diseases cause 76 million illnesses and 5000 deaths annually (7). WHO has estimated that each year 2.2 million people, including 1.9 million children, die because of diarrheal diseases (18). This and similar partial estimates provide valuable information, but they do not quantify the global burden of disease from contaminated food and water. WHO therefore convened a panel of experts, the Foodborne Disease Burden Epidemiology Reference Group (FERG), to conduct a more comprehensive assessment. The research reported here was intended to complement the work of the FERG and provide the panel with useful information about the extent of informal reporting of foodborne diseases in different world regions. Effective methods of disease surveillance can provide important information for assessing the burden of disease. This is admittedly a complicated task, as foodborne illnesses have many different symptoms, with both short- and longterm consequences. Although nausea and diarrhea are the most common symptoms, other consequences can include kidney and liver failure, brain and neural disorders, septicemia and death. For example, Listeria monocytogenes infection

has a mortality rate of 20–30%, including miscarriages (2). Some illnesses have long-term complications, such as reactive arthritis and paralysis, which can affect 2–3% of those who are infected (12, 13). Moreover, in many countries, because of economic difficulties, inadequate medical care, and lack of health insurance, medical attention is not sought, making accurate reporting of food and waterborne diseases difficult. For example, according to the Jordan Burden of Illness Study in 2003, only two in five persons with diarrhea sought medical care (6). Economic globalization has also increased the risk of outbreaks extending beyond national borders, underscoring the need for a comprehensive global assessment of the burden of food and waterborne illnesses. For example, in 2008, an outbreak caused by melamine contamination in infant formula caused sickness in 300,000, hospitalization of 52,000 and death in at least 6 infants in China; the outbreak, which extended to Hong Kong and Taiwan, sparked global recalls of products containing milk and milk ingredients from China (16). In developing nations, foodborne diseases are a primary cause of malnutrition, which adversely affects the growth and disease resistance of infants and children, making them more vulnerable to a range of ailments such as respiratory infections that contribute to the downward spiral of further malnutrition and disease. Patients can also suffer from arrested physical and mental development, preventing them from reaching their full potential in society (12). Food also plays a central role at the interface between human and animal diseases, because pathogens that evolve in animals can spread to humans through food. This commonly occurs today, as documented by disease outbreaks linked to Salmonella, Campylobacter and hemorrhagic strains of E. coli linked to both animal and plant food vehicles (11). Human practices in raising animals as food sources can lead to the emergence and spread of new pathogens and the development of antibiotic resistance in common animal pathogens, making it harder to treat the diseases they cause (4). Sometimes, emerging diseases begin at the animal level, e.g., highly pathogenic avian influenza and bovine spongiform encephalopathy, but are then transmitted through proximity to animals or through the food supply (10).

An accurate assessment of foodborne diseases is also important in order to quantify their economic burden. Foodborne diseases can contribute to absenteeism from work or school and can lead to high medical, legal and other expenses. The costs to national governments can include increased costs of health care, outbreak investigations, food recalls, and loss of consumer confidence. The best estimates of the economic costs of foodborne disease have come from developed countries. In the United States, for example, foodborne disease costs billions of dollars each year; government sources estimate the cost of human illnesses caused annually by seven foodborne pathogens at U.S. $5.6 to 9.4 billion, and a more recent estimate for the total burden of foodborne disease was $152 billion (5, 8). The cost of human Salmonella infections in England and Wales in 1992 was estimated at U.S. $560 to 800 million, over 70% of which was directly associated with treatment and investigation of cases and sicknessrelated absences from work (12). The cost of the estimated 11,500 cases of food poisoning daily in Australia was calculated at AU $2.6 billion annually (1). In the United Kingdom, care and treatment of people with the new variant of Creutzfeldt-Jacob disease (vCJD) would cost £50,000 per case. A £55,000 trust has been set up to care for up to 250 victims as part of the Government’s no-fault compensation scheme (9). For the year 2008, researchers at the Center for Science in the Public Interest (CSPI) analyzed the reporting of foodborne and waterborne illness outbreaks in public sources (news articles, scientific publications, and announcements by governments or international organizations) in English from every world region except North America. It is acknowledged that disease outbreaks that were documented and analyzed constitute a small portion of the true burden of foodborne disease, which clearly is much larger and should be quantified in countries all over the world.

MATERIALS AND METHODS
Data collection
In October 2007, Safe Food International (SFI), a project of CSPI, launched a data aggregation project to track outbreak reports linked to contaminated

484 FOOD PROTECTION TRENDS | AUGUST 2010

Food Protection Trends - August 2010

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