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

Climate impacts on socio-economic systems and health4.4.6 Vector-borne diseasesRelevanceClimate change can lead to significant shifts inthe geographic and seasonal distribution rangesof vector-borne diseases in Europe (Semenza andMenne, 2009).Climate can affect vector-borne diseases byshortening the life-cycles of vectors and theincubation periods of vector-borne pathogens,thereby potentially leading to larger vectorpopulations and higher transmission risks. Overthe longer term, seasonal changes could affectboth vectors and host animals, as well as humanbehaviours and land-use patterns, thereby furtherinfluencing the geographical distribution, seasonalactivity and overall prevalence of vector‐bornediseases in Europe (Lindgren et al., 2012).Furthermore, climatic suitability is essential for thearrival, establishment and spread of 'exotic' diseasesthat are not currently established in continentalEurope. In addition to climate, the spread ofcommunicable diseases depends on a range ofinterconnected ecological, economic and socialfactors, such as land-use patterns and fragmentation;biological diversity; the capacity of public healthsystems; travel, trade and migration; and humanbehaviours affecting individual risk factors (EEA,2010a; Suk and Semenza, 2011).Past trendsVector-borne diseases are an emerging publichealth issue in Europe. Lyme borreliosis is the mostcommon vector-borne disease in the EU, with areported incidence of approximately 85 000 casesper year. The mean number of reported cases oftick-borne encephalitis (TBE) in Europe has beenalmost 2 900 per year during the period 2000–2010(ECDC, 2011). However, these numbers need to beconsidered with care due to difficulties in diagnosisand case definition. Thus, the overall burden ofthese tick-borne diseases in Europe remains unclear.Mosquito-borne diseases have not been a substantialconcern within Europe until recently. However,locally transmitted outbreaks of Chikungunya,Dengue and even malaria have occurred in recentyears. Periodical outbreaks have been reported inGreece and possibly neighbouring countries forleishmaniasis, a disease transmitted by sandflieswhich naturally occur in southern Europe.Tick-borne diseasesTBE and Lyme borreliosis are the two mostimportant tick-borne diseases in Europe, transmittedprimarily by I. ricinus. A key determinant is theabundance of ticks, which is sensitive to climaticvariables, notably temperature. Climate changemay shift the distribution range of I. ricinus towardshigher latitudes and altitudes, as milder wintertemperatures, longer vegetation seasons and earlieronsets of summer appear and warmer temperaturesoccur (Jaenson and Lindgren, 2011). There havealready been reports on the northerly migration ofthe tick species in Sweden (Lindgren et al., 2000),and to higher altitudes in the Czech Republic(Daniel et al., 2003). Range shifts have also beenobserved in Germany and Norway (Semenza andMenne, 2009).Map 4.13 shows the risk of the Lyme diseasepathogen (Borrelia burgdorferi) in Europe. Highrisk is associated with mild winters, highsummer temperatures, low seasonal amplitude oftemperatures and high scores on vegetation indices(Estrada-Pena et al., 2011).There are considerable differences between thedistribution of ticks and the observed incidence ofTBE (Süss et al., 2006). There has been a markedKey messages: 4.4.6 Vector-borne diseases• The transmission cycles of vector-borne diseases are sensitive to climatic factors but also to land use,vector control, human behaviour and public health capacities.• Climate change is regarded as the main factor behind the observed northward and upward move of thetick species Ixodes ricinus in parts of Europe.• Climate change is projected to lead to further northward and upward shifts in the distribution ofI. ricinus. It is also expected to affect the habitat suitability for a wide range of disease vectors,including Aedes albopictus and phlebotomine species of sandflies, in both directions.Climate change, impacts and vulnerability in Europe 2012195