notifications reported a climate change risk, whereas those countries with incomplete (or no) Cryptosporidium notifications considered the risk to be low (Semenza and Nichols 2007). In this expert survey, outbreaks of water‑ borne diseases were considered less likely to be affected by climate change than food‑ or vectorb‑orne diseases. A total of 23 countries reported one or more waterb‑orne disease out ‑ breaks due to drinking water contamination in the last decade, with 12 reporting five or more outbreaks. For most countries, these numbers amounted to less than one outbreak every few years. No respondents thought that past water‑ borne disease outbreaks due to contaminated drinking water were attributable to actual cli‑ mate change; however, extreme weather events due to climate variability could be implicated. Low numbers of outbreaks of water‑borne diseases are a testament to high‑ quality water treatment in Europe, but this might also be due to underreporting because diarrheal symp‑ toms are reported to health care providers only if they are severe. Foodb‑orne infections linked with climate change were reported largely from central and Weak Needs signiﬁcant improvement Needs some improvement Very effective 35 30 25 20 15 10 5 0 trno IsD i e oom iitsv t n s e iitttuno t-saem .sn lic I 1 fro ks se ra e ic tb v u r tshe IoD l a e H . 2 ce sm llian rga rve rpo u s t n e r r u C . 3 tro ic supp ide m itsco ignep n ru iag d D . 4 ith tro w ce lli.trbaoaonC trryvsneae o i 5 ilam skea n r fa tb to uo n e e s m ae agen isd a M . 6 Figure 5. Responses from national infectious dis­ ease (ID) experts, 2009/2010, as to the effectiveness of institutions, health services, and surveillance pro­ grams for vector­ , water­ , and food­ borne diseases by EEA countries. The y­ axis represents the EEA countries, which included 27 EU member states plus Norway and Iceland, with the exception of Lichtenstein. Incomplete data are due to miss­ ing information. Data are based on the following survey questions: 1. Are there regional or local planning and coordination institutions to monitor and control climate­ sensitive IDs? 2. Are regional or local health services able to provide essen­ tial health services during an ID outbreak? 3. How effective are current surveillance and control pro­ grams for vector­ , water­ , and food­ borne diseases? 4. How effective is their capacity to provide routine and diagnostic support in case of an epidemic? 5. How effective is your collaboration with the veterinary sector with regard to both surveillance and responses to an outbreak? 6. How is an animal disease outbreak, with human health implications, managed in your country? eastern Europe. Salmonella and Campylobacter incidence display a distinct seasonal pattern that has been associated with climate variability (increased temperatures, heat waves, and flood‑ ing) (Bentham and Langford 2001; Kovats et al. 2004, 2005; Lake et al. 2009). However, animal control measures and other public health interventions have led to decreasing risk in several European countries, which may over‑ shadow any potential effects of climate change. Survey respondents did not attribute food‑ borne outbreaks in their countries to climate change, despite evidence of strong correlations between temperature and disease incidence reported in the literature (Kovats et al. 2004). Planning and preparedness. Regional cli‑ mate change impacts are a function of local vulnerabilities, exposure, and changing weather variables. The ability to adapt depends on a number of factors, such as surveillance infor‑ mation, human resources, available technol‑ ogy, institutional capacity, economic resources, social equity, and political will (Huang et al. 2011). In our analysis we attempted to cap‑ ture some of these planning and preparedness activities. The majority of experts (17 of 29) acknowledged research on climate‑sensitive infectious diseases in their countries; however, few institutions are in place to monitor climate‑ sensitive infectious diseases (14 of 29), and the majority of these institutions need improve‑ ment. Respondents from only seven countries indicated that their country had conducted a national climate change assessment that covered infectious diseases extensively or adequately, but onet‑hird of the countries with a response plan were anticipating the need for increasing human and material resources to address risks from climate change (Figure 4 and Table 3). Surveillance activities. Approximately 80% of government officials indicated that their cur‑ rent surveillance activities needed at least some improvement (Figure 4D). Establishing syndro‑ mic surveillance systems (which monitor health‑ related data that precede diagnosis, such as emergency calls, school absenteeism, pharmacy‑ based drug sales, and Internet queries) could be one way of enhancing surveillance because they can capture realt‑ime trends, geographic spread, or outbreaks that would otherwise go unnoticed, thereby complementing ongoing surveillance activities. Surveillance of potential new risk regions where climates‑ensitive patho ‑ gens or disease vectors may become introduced and established is also of considerable impor‑ tance, such as for dengue fever surveillance in the Mediterranean region. Vector, environ‑ mental, or drinking water surveillance are other approaches that could be considered. Limitations. Our study has a number of limitations. Expert opinions can be vulnerable to recall bias, susceptible to institutional or disciplinary biases, shaped by recent disease outbreaks, influenced by increased media Environmental Health Perspectives • volume 120 | number 3 | March 2012 Climate change vulnerability mapping reporting, and so on. Experts in this study were officially nominated by government agencies as the point person for climate change in their country (ECDC 2011), as is standard practice for other infectious disease programs within the ECDC. However, no independent assessment of their professional or academic expertise was conducted. The data collected were not subjected to thirdp‑arty verification and might thus contain inaccuracies and misconstructions. Nevertheless, we compared the different survey results with data from the peer‑reviewed literature and the national reports sent to the UNFCCC (2010). The survey result was remarkably consistent with the other sources we examined, with the exception of food‑ borne diseases, which highlights potential food security issues (food safety, food production, etc.) related to climate change. This expert assessment of national representatives likely corresponds with the government opinion on this topic. Although the data represent perceived impacts, our expert analysis can also shed light on the extent of scientific consensus and thus inform public policy (Van Rij 2010). Conclusion Attributing single infectious disease epidemics to climate change is not possible, but longer‑ term trends in disease outbreaks and incidence may signal linkages to climate variations. The exact attribution of changes in specific infectious disease risks to climate change is probably not attainable. Nonetheless, pub‑ lic health practitioners are obliged to address credible risks—even if that requires acting in the absence of conclusive evidence. Expert opinion can provide pivotal insights and guide climate change adaptation in a field with complex interacting drivers (Suk and Semenza 2011). National expert opinion concerning risks of vector‑ and water‑borne diseases from climate change matched well with data from the peer‑reviewed literature, but less well for foodb‑orne diseases where the causal link has a range of potential confound‑ ers. National climate change assessments were reported mainly from Western Europe, and a number of institutional weaknesses were identified, such as research on and control of climate‑ sensitive infectious diseases. Most noticeable, however, was the need to improve current surveillance of infectious diseases. Current deficiencies are of particular concern given budgetary shortfalls for infectious disease programs during economic crises, as we docu‑ mented recently (Rechel et al. 2011; Suhrcke et al. 2011). The ECDC developed a handbook for climate change impact, vulnerability, and adaptation assessment to assist member states with this process (ECDC 2010b). Ultimately, vigilant surveillance, the cornerstone of public health practice, will likely be ever more impor‑ tant for addressing climate change threats. 391