Spatial modelling of the potential temperature-dependent transmission of vector-associated diseases in the face of climate change: main results and recommendations from a pilot study in Lower Saxony (Germany)

Abstract

The sustained climate change is going to modify the geographic distribution, the seasonal transmission gate and the intensity of the transmission of vector-borne diseases such as malaria or the bluetongue disease. These diseases occur nowadays at higher latitudes or altitudes. A further rise in ambient temperature and rainfall will extend the duration of the season in which mosquito vectors are transmitting pathogens. The parasites transmitted by the vectors also benefit from increasing temperatures, as both their reproduction and development are then accelerated, too. Thus, it seemed prudent to examine potential effects on the seasonal transmission gate due to the ongoing and predicted climate changes. Lower Saxony (northwest Germany) is a former malaria region with highest incidences of Anopheles atroparvus and tertian malaria along the coastal zones before malaria had finally become extinct in the early 1950s. Nevertheless, the Anopheles mosquitoes which transmit the malaria pathogens have still been present in Lower Saxony up to now. This together with the climate change-related implications gave reason to investigate whether a new autochthonous transmission could take place if the malaria pathogen is introduced again in Lower Saxony. Thus, the potential spatial and temporal structure of temperature-driven malaria transmissions was mapped using the basic reproduction rate (R (0)) and measured and predicted air temperatures (1947-1960, 1961-1990, 1985-2004, 2020, 2060, 2100, each best case and worst case scenario). This paper focuses on both the summarizing of the results from this risk modelling approach and on the conclusions to be drawn. The recommendations highlight the need to link vector monitoring as one of the key elements of an epidemiological monitoring with the environmental monitoring.

Systematic Assessment of the Climate Sensitivity of Important Human and Domestic Animals Pathogens in Europe

“…Climate change is expected to threaten human health and well-being via its effects on climate-sensitive infectious diseases, potentially changing their spatial distributions, affecting annual or seasonal cycles, altering disease incidence and in some cases disease severity 1 . There is a growing body of evidence suggesting that climate change is already driving certain diseases to higher latitudes 2 , 3 or altitudes 4 , and the expectation must be that such effects will continue, and perhaps accelerate in future, as the global climate continues to warm and rainfall patterns change. But while some diseases appear to be responding to climate change, many do not 5 .…”

Current situation of Leishmania infantum infection in shelter dogs in northern Spain

“…In Germany, it has been estimated that some 20,000 infected dogs have been imported by tourists from endemic zones in southern Europe [7]. The presence of reservoirs and the detection of one of the parasite's main vectors, Phlebotomus perniciosus , in central European countries, such as Switzerland [10] or Germany [11], suggest the possible emergence of the disease at latitudes where it did not traditionally exist [12-14]. In effect, the distribution range of leishmaniosis across the European continent is no longer limited to the Mediterranean basin and, recently, new disease foci have been detected at the foothills of mountain ranges such as the Alps [15,16] or Pyrenees [17].…”

Anopheles atroparvus density modeling using MODIS NDVI in a former malarious area in Portugal

“…It is estimated that in 2006 there were 247 million cases of malaria, with 881,000 deaths, of which 92% were children under the age of five, not accounting for the large indirect burden on morbidity and mortality (WHO 2008). In temperate regions, malaria is considered as a potentially re‐emerging disease due to ongoing environmental and temperature changes (Lindsay and Birley 1996, Patz et al 2005, Schroder and Schmidt 2008), land use changes (Lindblade et al 2000, Patz et al 2004, Munga et al 2009) and increases in tourism fluxes (Linard et al 2009).…”