Guess Who’s Coming to Dinner? Emerging Foodborne Zoonoses

Foodborne infectious diseases sicken millions of Canadians every year, and are a major source of economic costs related to outbreak control, economic losses for food producers and vendors, and productivity costs among sickened individuals. Recent estimates suggest that more than 35 million cases of acute gastroenteritis occur in Canada annually, with an annual cost of more than $3 billion (1); a majority of such illnesses are caused by contaminated food or water. Foodborne infections may also cause severe illness or even death, especially among individuals at the extremes of age and those with impaired immune functions (2). Common foodborne pathogens include commensal flora or pathogens found in animals consumed for food, those found in animal-derived products (eg, Listeria species in cheese and deli meats) (3,4) or those found in produce due to the contamination of fields with animal waste (5). Many foodborne illnesses are reasonably classified as zoonoses, and represent a good exemplar of the importance of the emerging ‘one health’ approach that links human and veterinary disease control efforts (6). Recent challenges in the control of foodborne infectious diseases include centralization and industrialization of farming and food processing (7,8), internationalization of food distribution (9) and the related globalization of cuisines (10). Similar to other infectious diseases, the apparent spectrum of foodborne pathogens has also changed as a result of the improved sensitivity of diagnostic methods, and some diseases that have historically been classed as vector-borne or waterborne are now being identified as transmitted through foods. As Canada emerges as a global hub for immigration, commerce and travel, it becomes increasingly important for Canadian clinicians to be aware of emerging infectious diseases in other geographical locales. In the present note, we describe the clinical features and evolving epidemiology of four emerging foodborne zoonoses.