Development of Aedes albopictus risk maps
|Project type:||Short Term RTD|
|Funding agency:||ECDC (Stockholm, Sweden)|
|Geographic keyword: Europe|
|General keyword: Disease modeling|
|Specific keyword: Invading species | Mosquitoes | Aedes albopictus|
Following the 2005-2006 outbreaks of Chikungunya virus in the Indian Ocean islands and more recently in Italy (summer 2007), the ECDC has requested expert advise in entomology to ensure a comprehensive understanding of the vector-related risk for introduction, establishment and spread of the virus in Europe. An entomology expert meeting was organized in Paris in October 2007 and several recommendations were proposed. Among these recommendations is the need to develop maps depicting the current presence of Ae. albopictus in Europe as well as to highlighting the areas at risk of introduction of the mosquito.
The objectives of TigerMaps, in accordance with the request for offer, are two-fold:
- To produce a map that shows the precise current distribution of Ae. albopictus in Europe:
"The first map, representing the current distribution of Ae. albopictus in Europe, should be based on vector surveillance data available on regional and/or national level in the countries. This map should make a distinction between areas with vector surveillance systems present, reporting positive or negative results, and areas without vector surveillance systems or data available. Second, where possible, the map should differentiate whether in a specific area the vector is present only in limited foci, or whether it is established rather in a widespread manner."
- To map the risk for establishment of Ae. albopictus in Europe, in the event of it being introduced:
"The four main climatic factors considered to be relevant to map the risk of establishment and abundance of Ae. albopictus if introduced to an area, have been agreed to be: winter temperatures, annual rainfall, summer rainfall and summer temperatures. Thus, a map based on climatic scenarios should be developed in order to show the risk of establishment of the vector, if introduced. For the best possible result, all four factors need to be studied separately, followed by the identification of the best possible combination of all factors. Ideally, a dynamic model is needed, considering the weight of each of the determinants.
If possible and considered relevant, the number of weeks of vector activity could also be incorporated."
In order to synergize the best competences related to these objectives, a consortium has been established, coordinated by Avia-GIS and grouping four confirmed experts with relevant and complementary experience/expertise in the field of insect vector/disease mapping/modeling in general and Ae. albopictus in particular:
- Guy Hendrickx, leader in GIS spatial predictive modeling;
- Jolyon Medlock, expert in emerging vector borne diseases and modeling;
- Francis Schaffner, leader in vector systematics and biology, specialist for Ae. albopictus;
- Ernst-Jan Scholte, expert in surveillance of introduced vectors.
Legend to the figures:
Figure 1: Areas for possible establishment of Aedes albopictus in Europe based on 5 climate scenarios. The image shows likelihood for the establishment. Scenario 1 (light yellow) = 450mm annual rainfall, -1°C January isotherm, scenario 2 (yellow) = 500mm rainfall, 0°C–scenario 3 (orange) = 600mm, 1°C – scenario 4 (red) = 700mm, 2°C – scenario 5 (brown) = 800mm rainfall, 3°C Source: Unpublished map made by Medlock J. & Schaffner F., based upon Medlock et al. 2006 – Analysis of potential for survival and seasonal activity of Aedes albopictus in the UK. J Vector Ecol. 31 (2): 292-304.
Figure 2: The image shows likelihood for periods of activity, based on criteria for establishment (-1°C January isotherm and 450mm annual rainfall) and criteria for activity (10.5°C, 11.25hrs daylight, autumn diapause threshold 13.5hrs daylight). Source: Unpublished map made by Medlock J. & Schaffner F., based upon Medlock et al. 2006 – Analysis of potential for survival and seasonal activity of Aedes albopictus in the UK. J Vector Ecol. 31 (2): 292-304.
Figure 3: Predicted non-Australasian potential distribution of Ae. albopictus. Darker shades indicate greater numbers of models in agreement for suitable habitat with the darkest shades signifying 10 models with the legend showing each. Source: Benedict MQ, Levine RS, Hawley WA and Lounibos P, 2007. Spread of the Tiger: Global Risk of Invasion by the Mosquito Aedes albopictus. Vector-borne and zoonotic diseases 7(1):76-85.