Semenza et al. temperatures of importance for the activity and survival of the vector (Lindgren et al. 2000). The experts who participated in the survey stated that with climate change, Lyme bor‑ reliosis is expected to change its altitude and latitude distribution (Figure 1A). This is in accordance with the literature regarding both observed relationships between climate varia‑ tions and tickb‑orne disease incidence over the last four to five decades (Daniel et al. 2009; Kaiser 1995; Lindgren and Gustafson 2001) and projected changes (Jaenson and Lindgren 2011), which estimate Lyme borreliosis becom‑ ing more prevalent in northern and central Europe and expanding to higher latitudes and altitudes. However, contributing factors other than climate, such as socioeconomic changes, may play important roles as well, particu‑ larly in central and eastern regions of Europe (Randolph 2008). Emerging concerns for some of the vector‑ borne diseases, in particular chikungunya and dengue fevers, were reflected in the differences in answers between the survey periods No national assessment National assessment No data No planning and coordination institutes Planning and coordination institutes No data N 0 190 380 760 1,140 1,520 Kilometers N 0 225 450 900 1,350 1,800 Kilometers 390 (Table 1). This could be explained in part by increased awareness among experts in the wake of recent outbreaks, such as the first‑ ever European chikungunya outbreak in Italy in 2007 (Rezza et al. 2007). Experts reported observed changes in their countries in the seasonality of hantavirus (Figure 1C). In the Nordic countries, larger outbreaks of hantavirus have been associated with lack of snow cover, which forces rodents, the vector of hantavirus, to move closer to and inside human buildings. Large epidemics occurred, for example, during the exception‑ ally mild and snowless winter of 2006/2007 in northern Sweden (Evander and Ahlm 2009). Leishmaniasis transmitted by sandflies is currently prevalent only in southern Europe, where the experts did not consider it likely to be affected by climate change (Figure 1D). Sandfly vectors, as well as the protozoa, are very sensitive to ambient temperatures. In fact, there are indications that the geographic distribution of leishmaniasis has expanded, and locally infected cases have now been documented in southern Germany (Lindgren et al. 2006; Naucke and Schmitt 2004). Food- and water-borne diseases. Water‑ borne diseases display a strong seasonality (Schijven and de Roda Husman 2005), and experts in northern and eastern Europe con‑ sidered these diseases likely to be affected by climate change (Figure 3A,B). Leptospirosis can be transmitted by water contaminated with urine and fecal matter from infected ani‑ mals, such as the floodwaters in the Czech Republic in 1997. Projected increases in the intensity and fre‑ quency of rainfall in the northern regions could lead to Cryptosporidium infiltration in water‑ treatment and distribution systems (Semenza and Nichols 2007). Respondents from north‑ ern European countries reported a potential increase in climate change risk, as opposed to those from southern European countries, where projected decreases in precipitation could reduce these risks (Figure 3B). However, these observations also reflect reporting bias; those countries with better EU Cryptosporidium 0 190 380 760 1,140 1,520 Kilometers N N 0 190 380 760 1,140 1,520 Kilometers Infectious disease risk not considered Infectious disease risk considered No data Surveillance needs improvement Surveillance needs no improvement No data Figure 4. Responses from national infectious disease experts, 2009/2010, as to whether their countries had (A) performed national assessments of health impacts from climate change; (B) considered infectious disease health risk as a result of climate change; and (C) developed local planning and coordination institutes to monitor and control climates­ensitive infectious diseases. ( D) They were also asked to rate the effectiveness of their country’s surveillance and control programs for vector,­ water,­ and foodb­orne diseases. ovlume 120 | number 3 | March 2012 • Environmental Health Perspectives