Climate change, impacts and vulnerability in Europe ... - MemoFin.fr

Climate impacts on socio-economic systems and healthcontaminated waters (Lindgren et al., 2012). Floodsand increased water flows can lead to contaminationof drinking, recreational or irrigation water and thusincrease the risk of water-borne diseases, such ascryptosporidiosis.It is not currently possible to attribute past trends inthese diseases, or individual outbreaks, to climatechange due to data gaps for selected pathogens andclimatic determinants. The current knowledge onthe relationship between climatic factors and the riskassociated with several climate-sensitive food- andwater-borne diseases (caused by bacteria, virusesand parasites) in Europe is presented below.CampylobacterIncidence of campylobacteriosis has been linkedto mean temperatures, though not consistently(Fleury et al., 2006; Bi et al., 2008). High ambienttemperatures and relatively low humidity have beenlinked with increased incidence (Patrick et al., 2004;Lake et al., 2009). Assessment of this relationship isdifficult, as Campylobacter does not replicate outsideits animal host and the seasonal incidence peakdoes not occur during the hottest time of the year.Rain in early spring can trigger campylobacteriosisoutbreaks (WHO, 2008b). Outbreaks tend to occurmore often in rural areas, where households aresupplied by private water sources, more susceptibleto contamination during extreme weather events(Pebody et al., 1997; Hearnden et al., 2003). Withthe projected increase in heavy rainfall eventsin northern Europe, the risk of surface andgroundwater contamination is expected to rise.Climate change might increase the use of rainwaterduring times of drought in certain locations. If theharvesting of rainwater increases, Campylobacter inuntreated roof run-off water might contribute to anincreased risk of both animal and human disease(Palmer et al., 1983; Savill et al., 2001).SalmonellaA raise in weekly temperature is followed byan increase in salmonellosis in different settings(Naumova et al., 2006; Zhang et al., 2007; Nicholset al., 2009). Ambient seasonal temperatures aresuspected drivers of reported salmonellosis cases,but an influence of temperature might be attenuatedby public health interventions (Lake et al., 2009).Seasonal detection frequencies for Salmonella sp.in water environments were related to monthlymaximum precipitation in summer and fallfollowing faecal contamination events (Craig et al.,2003; Martinez-Urtaza et al., 2004). Floods caused byheavy rainfall events may disrupt water treatmentand sewage systems and contribute to increasedexposure to Salmonella sp. and other pathogens.Salmonellosis continues to decline in Europe overthe last decade, in part due to control measures.Thus, health promotion and food safety policiesshould be able to mitigate adverse impacts on publichealth.Available projections indicate that by the 2020s,under the A2 scenario, the average annual numberof temperature-related cases of salmonellosis inEurope may increase by almost 20 000 as a result ofclimate change, in addition to increases expectedfrom population changes. By the 2071–2100 period,climate change could result in up to 50 % moretemperature-related cases than would be expectedon the basis of population change alone. However,these estimates need to be interpreted with caution,due to high uncertainty (Watkiss and Hunt, 2012).CryptosporiumHeavy rainfall has been associated with thecontamination of water supplies and outbreaks ofcryptosporidiosis (Aksoy et al., 2007; Hoek et al.,2008), as the concentration of Cryptosporidiumoocysts in river water increases significantly duringrainfall events. Dry weather conditions precedinga heavy rain event has also been associated withdrinking water outbreaks (Nichols et al., 2009). Thus,heavy precipitation can result in the persistence ofoocysts in the water distribution system and theinfiltration of drinking water reservoirs from springsand lakes. A rise in precipitation is predicted tolead to an increase in cryptosporidiosis, althoughthe strength of the relationship varies by climatecategory (Jagai et al., 2009)NorovirusFood-borne norovirus outbreaks have been linkedto climate and weather events; for example, heavyrainfall and floods may lead to wastewater overflowwhich can contaminate shellfish farming sites. Floodwater has been associated with a norovirus outbreakin Austria (Schmid et al., 2005). The magnitude ofrainfall has also been related to viral contaminationof the marine environment and with peaks indiarrhoea incidence (Miossec et al., 2000). Thepredicted increase of heavy rainfall events underclimate change scenarios could lead to an increase innorovirus infections because floods are known to belinked to norovirus outbreaks.200 Climate change, impacts and vulnerability in Europe 2012