“Malaria has a one way airline ticket to visit you!”
Zhuojie, H., Das, A., Youliang, Q., & Tatem, A. J. (2012). Web-based GIS: the vector-borne disease airline importation risk (VBD-AIR) tool. International Journal Of Health Geographics, 11(1), 33-46. doi:10.1186/1476-072X-11-33 (accessed February 2, 2014).
The past decade has seen a dramatic increase in international travel and now passengers can travel around the world in a matter of hours. However, this also increases the risk of diseases being spread around the world or vector-borne diseases, such as malaria, dengue, yellow fever, and chikungunya, establishing themselves in new locations. In their study, Zhuojie et al. (2012) use the GIS tool Vector-Borne Disease Airline Importation Risk Tool (VBD-AIR) to study how vector-borne diseases can spread by using international air routes. Current models are static and do not take into account climate-driven seasonal fluctuations that can prevent vector-borne diseases from spreading to a new location.
For example, I fly to Rio de Janeiro in February for carnival and do not return back to Austin until June. While there I get bitten by mosquitoes and some of them just happen to hitch a flight back to Austin via the aircraft’s wheel well. Under this scenario, my mosquito friends may establish themselves in Austin and being spreading malaria in Central Texas. If I returned back to Austin during the month of February, then there would be a low risk of mosquitoes from Brazil surviving in Austin because of the winter season. Current models do not account for seasonal variations.
Color scale indicates predicted unsuitable to suitable conditions as a continuous scale from yellow to dark blue.
A) Predicated distribution of chikungunya outbreaks
B) Climatic and environmental suitability of Aedes albopictus (mosquito that carries malaria)
VBD-AIR uses data from airport locations, air routes, disease and vector distributions, global climate data, and travel time. For this reason, VBD-AIR is a better tool to use in anaylizing the spread of vector-borne diseases.
Malaria, dengue, yellow fever, and chikungunya are transmitted by mosquitoes. Non-endemic countries are seeing increasing cases of these diseases among travelers or returning migrants. Dengue fever has seen a reemergence due to air travel. The same is occurring with yellow fever, but the disease has spread from South America and Africa to Asia, where it is not commonly found. As for chikungunya, the disease has spread its range.
Zhuojie et al. (2012) use three types of mosquitoes for VBD-AIR: Aedes aegypti, Aedes albopictus, and Anopheles. Aegypti, which spreads dengue fever, chikungunya, and yellow fever, is native in Africa, but it is now found in tropical regions throughout the world. Albopictus can spread dengue, yellow, fever, and West Nile virus; however, this type of mosquito is a poor vector in spreading diseases. Anopheles transmits malaria. In order for these mosquitoes to establish themselves in a new area, they need the right temperature, rainfall, and humidity.
The enemy! Aedes albopictus
Next, the authors used VBD-AIR to create a website were air travelers can visit to create a risk assessment of their travels and vector-borne diseases. Travelers can now see how vector distribution, seasonal climate changes, and changing air traffic are interrelated in spreading vector-borne diseases. VBD-AIR illustrates how different regions, airports, and air routes carry varying risks in spreading vector diseases.
VBD-AIR can be used to model health risks and assist medical personnel in screening patients who just returned from overseas travel. Furthermore, VBD-AIR helps travelers to assess their risks to vector-borne diseases so that they can better protect themselves. Next time I travel abroad, I’ll use VBD-AIR and prevent mosquitoes from hitching a ride back home with me.