Water and food-borne diseases
- There has been a linear increase in reported cases of some food-borne diseases for each degree increase in weekly or monthly temperature over a certain location-specific threshold (medium confidence). Several thousand cases of salmonella are expected in future years, particularly in countries where food safety standards are poor.
- Changing frequency and intensity of precipitation events (and temperature) from climate change may result in outbreaks of water-borne diseases (high confidence) and could mobilise pathogens.
- In the Mediterranean additional salmonella problems from bathing water quality are projected, which would require proper monitoring and surveillance.
Percentage change of weekly salmonella cases by 1 oC temperature increase
Note: The figure shows the percentage change of weekly salmonella cases 1 degree Celcius temperature increase
Kovats, R. S.; Edwards, S.; Hajat, S. et al., 2004. The effect of temperature on food poisoning: time series analysis in 10 European countries. Epidemiology and Infection 132 (3): 443.
Access to public sources of drinking water in EU Member States is high. Heavy precipitation has been linked to a number of drinking-water outbreaks of Cryptosporidium (a pathogen causing a diarrhoeal illness) in Europe, due to spores infiltrating drinking water reservoirs from springs and lakes and persisting in the water distribution system (Lake et al., 2005; Semenza and Nichols, 2007). In Germany, bacteriological and parasitic parameters spiked considerably during extreme runoff events (Kistemann et al., 2002). New pathogens have also emerged in recent years. In Europe the risk of infectious disease outbreaks is relatively small due to the standard of water treatment and distribution infrastructure. While water-borne outbreaks have a rather large potential, the actual disease burden in Europe is difficult to estimate and is most probably underestimated. Examples of an increased risk of infectious disease outbreaks have been found in the United Kingdom (Reacher et al., 2004), Finland (Miettinen et al., 2001), Czech Republic (Kriz et al., 1998) and Sweden (Lindgren, 2006).
Key food- and water-borne infections in Europe are monitored. The incidence of salmonella has been declining in many countries, but that of other pathogens is increasing. Several studies have confirmed and quantified the effects of high temperatures on common forms of food poisoning, such as salmonellosis (D'Souza et al., 2004; Kovats et al., 2004; Fleury et al., 2006) (see Figure 1). These found an approximately linear increase in reported cases with each degree increase in weekly or monthly temperature over a certain threshold. Temperature is much less important for the transmission of Campylobacter (Kovats et al., 2005; Louis et al., 2005; Tam et al., 2006). Contact between food and pest species, especially flies, rodents and cockroaches, is also temperaturesensitive. Fly activity is largely driven by temperature rather than by biotic factors (Goulson et al., 2005).
Harmful algal blooms (HABs) produce toxins that can cause human diseases, mainly via consumption of contaminated shellfish. Warmer seas may thus contribute to more cases of human shellfish and reef-fish poisoning (ciguatera) and poleward expansions of these disease distributions (Lehane and Lewis, 2000; Hall et al., 2002; Hunter, 2003; Korenberg, 2004).
Infections with Salmonella spp. increase by 5-10 % for each degree increase in weekly temperature, at ambient temperatures above 5 oC (Kovats et al., 2004). Some emerging studies show that the disease burden in Europe could be significant (all else being constant) with potentially an extra 20 000 cases per year by 2030 and 25 000-40 000 by 2080 (EC, 2007).
Water stress over central and southern Europe is projected to increase. In the EU, the percentage of land area under high water stress is likely to increase from 19 % today to 35 % by the 2070s, by when the number of additional people affected is expected to be between 16 and 44 million. Furthermore, in southern Europe and some parts of central and eastern Europe, summer water flows may be reduced by up to 80 %. By 2025 it is projected that an additional 31 million people will be living in the coastal zone of the Mediterranean, and that 130 million more will visit the region each year.
Indicator specification and metadata
- Percentage change of weekly salmonella cases by 1 0C temperature increase
Policy context and targets
In April 2009 the European Commission presented a White Paper on the framework for adaptation policies and measures to reduce the European Union's vulnerability to the impacts of climate change. The aim is to increase the resilience to climate change of health, property and the productive functions of land, inter alia by improving the management of water resources and ecosystems. More knowledge is needed on climate impact and vulnerability but a considerable amount of information and research already exists which can be shared better through a proposed Clearing House Mechanism. The White Paper stresses the need to mainstream adaptation into existing and new EU policies. A number of Member States have already taken action and several have prepared national adaptation plans. The EU is also developing actions to enhance and finance adaptation in developing countries as part of a new post-2012 global climate agreement expected in Copenhagen (Dec. 2009). For more information see: http://ec.europa.eu/environment/climat/adaptation/index_en.htm
No targets have been specified
Related policy documents
No related policy documents have been specified
Methodology for indicator calculation
Methodology for gap filling
No methodology references available.
Data sets uncertainty
Four main issues should be considered when evaluating the relationship between health outcomes and exposure to changes in rainfall and water availability and quality: (1) links between water availability, household access to improved water and the health burden due to diarrhoeal diseases; (2) the role of extreme rainfall (intense rainfall or drought) in facilitating water-borne outbreaks; (3) effects of temperature and runoff on microbiological and chemical contamination of coastal, recreational and surface waters; (4) direct effects of temperature on the incidence of diarrhoeal and other diseases. Climate variability and change also change the risks of fires and pest and pathogen outbreaks, with negative consequences for food, fibre and forestry (Menne et al., 2008).
Access to safe water remains an extremely important global health issue. The risk of outbreaks of water-borne diseases increases where standards of water, sanitation and personal hygiene are low.
Extreme precipitation events leading to floods or droughts can have direct and indirect health effects. Flooding can cause drowning, injuries (cuts, sprains, laceration, punctures, electric injuries, etc.), diarrhoeal diseases, vector-borne diseases (including those borne by rodents), respiratory infections, skin and eye infections, and mental health problems. Floods also have other effects with health consequences: damage to infrastructure for health care and water and sanitation, crops (and/or disruption of food supply) and property (lack of shelter), and disruption of livelihood and displacement of populations. Droughts or extended dry spells can impair provision of safe water leading to water-related health problems, for example through reducing the volumes of river flow, which may increase the concentration of effluent pathogens, posing a problem for the clearance capacity of treatment plants.
Climate change is also likely to affect the quality of coastal waters, by changing natural ecosystems or the quality of the waters draining into the coastal zone. This poses specific risks for the recreational use of bathing waters, particularly for transient tourist populations that may not have built-in resistance to endemic water-related diseases or may be faced with water quality that does not meet the stringent conditions imposed in the home country. The quality and safety of seafood is directly linked to the quality of the water in the coastal zone.
Intestinal infectious diseases that are transmitted through food or water are sensitive to climate and weather factors. Such diseases are the main causes of infectious diarrhoea and cause significant amounts of illness each year in Europe. Approximately 20 % of the population in western Europe is affected by episodes of diarrhoea each year (van Pelt et al., 2003). Such infections have a significant economic impact in terms of treatment costs and loss of working time (Roberts et al., 2003).
Various adaptation options are available, which include ensuring access to safe drinking water, providing sanitation services, and establishing common standards for surveillance systems and contingency plans for detecting and preventing water-borne disease outbreaks. Water-safety plans may need to be revised for changing climate conditions. Such plans will need to include ways of ensuring safe drinking water from source to tap through better risk assessment and management. Improved management of water demand in the context of fully-integrated planning for river-basin management will become imperative as a first coping mechanism, but is unlikely to satisfy all the needs created by demographic growth, rising living standards and economic development. Alternative strategies will need to be explored, including reusing treated wastewater, using grey water, harvesting rainwater and, where economically viable, desalination. Contamination of food products usually arises from improper practices at some point during the journey from farm to fork. Providing education and timely information on the best ways to handle food and avoid food-borne diseases to producers, food handlers and consumers is essential. Food-borne disease outbreaks can be prevented by using safe water and raw materials, keeping food clean and at safe temperatures, cooking food thoroughly, and keeping raw and cooked food separate.
Effect of temperature on food poisoning
provided by London School of Hygiene and Tropical Medicine
Climate change (Primary topic)
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
- CLIM 038
Contacts and ownership
EEA Contact InfoHans-Martin Füssel
EEA Management Plan2008 2.3.1 (note: EEA internal system)
For references, please go to www.eea.europa.eu/soer or scan the QR code.
This briefing is part of the EEA's report The European Environment - State and Outlook 2015. The EEA is an official agency of the EU, tasked with providing information on Europe’s environment.
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