The number of travel-acquired dengue infections has been on a constant rise in the United States and Europe over the past decade. An increased volume of international passenger air traffic originating from regions with endemic dengue contributes to the increasing number of dengue cases. This paper reports results from a network-based regression model which uses international passenger travel volumes, travel distances, predictive species distribution models (for the vector species), and infection data to quantify the relative risk of importing travel-acquired dengue infections into the US and Europe from dengue-endemic regions. Given the necessary data, this model can be used to identify optimal locations (origin cities, destination airports, etc.) for dengue surveillance. The model can be extended to other geographical regions and vector-borne diseases, as well as other network-based processes. 1. Introduction Dengue is the most common mosquito-borne viral diseases in the world [1]. Although it is not currently endemic to either Europe or the continental United States, except along the Texas-México border and possibly Florida, an increase in dengue occurrence in many of the endemic regions worldwide, in conjunction with a significant rise in the volume of international air travel, has resulted in a greater likelihood of imported dengue infections among travelers returning to the United States and Europe from dengue-endemic regions [2]. It has also increased the potential for transport and establishment of the mosquito vector species in those regions of Europe and the U.S. in which suitable habitat is available. The causal agent for dengue is a virus that is transmitted from person to person through the bite of infected Aedes mosquitoes (mainly Ae. aegypti and Ae. albopictus), with humans serving as the main viral host [1]. The geographic establishment of dengue is thought to be limited purely by the occurrence of its principal vector mosquito species, Ae. aegypti and Ae. albopictus. Both species have proven to be highly adaptable to human habitation and, as a result, the global spread of the vector has been difficult to contain [1]. Dengue is considered endemic to urban and suburban areas in parts of tropical and subtropical America, part of Australia, South and Southeast Asia, the Pacific, and eastern Africa. In addition, the number of imported cases of dengue in the U.S. and Europe is on the rise and further spread and establishment are anticipated [2, 3]. At present, there is no epidemiological surveillance on a national scale in Europe or at the
References
[1]
World Health Organization: Dengue (WHO), http://www.who.int/topics/dengue/en/, 2010.
[2]
A. Wilder-Smith and D. J. Gubler, “Geographic expansion of Dengue: the impact of international travel,” Medical Clinics of North America, vol. 92, no. 6, pp. 1377–1390, 2008.
[3]
D. J. Gubler, P. Reiter, K. L. Ebi, W. Yap, R. Nasci, and J. A. Patz, “Climate variability and change in the United States: potential impacts on vector- and Rodent-Borne diseases,” Environmental Health Perspectives, vol. 109, no. 2, pp. 223–233, 2001.
[4]
European Center for Disease Control (ECDC), http://www.ecdc.europa.eu/, 2010.
[5]
Centers for Disease Control and Prevention, “Locally acquired Dengue—Key West, Florida, 2009-2010,” Morbidity and Mortality Weekly Report, vol. 59, no. 19, pp. 577–581, 2010.
[6]
Centers for Disease Control and Prevention, “Dengue hemorrhagic fever—U.S.-Mexico Border, 2005,” Morbidity and Mortality Weekly Report, vol. 56, no. 31, pp. 785–789, 2007.
[7]
A. T. A. Mairuhu, J. Wagenaar, D. P. M. Brandjes, and E. C. M. Van Gorp, “Dengue: an arthropod-borne disease of global importance,” European Journal of Clinical Microbiology and Infectious Diseases, vol. 23, no. 6, pp. 425–433, 2004.
[8]
TropNetEurope: European Network on Imported Infectious Disease Surveillance, http://www.tropnet.net/index_2.html, 2010.
[9]
T. Jelinek, N. Mühlberger, G. Harms et al., “Epidemiology and clinical features of imported dengue fever in Europe: sentinel surveillance data from TropNetEurop,” Clinical Infectious Diseases, vol. 35, no. 9, pp. 1047–1052, 2002.
[10]
A. J. Tatem, S. I. Hay, and D. J. Rogers, “Global traffic and disease vector dispersal,” Proceedings of the National Academy of Sciences of the United States of America, vol. 103, no. 16, pp. 6242–6247, 2006.
[11]
C. González, O. Wang, S. E. Strutz, C. González-Salazar, V. Sánchez-Cordero, and S. Sarkar, “Climate change and risk of leishmaniasis in North America: predictions from ecological niche models of vector and reservoir species,” PLoS Neglected Tropical Diseases, vol. 4, no. 1, Article ID e585, 2010.
[12]
S. Sarkar, S. E. Strutz, D. M. Frank, C. L. Rivaldi, B. Sissel, and V. Sánchez-Cordero, “Chagas disease risk in Texas,” PLoS Neglected Tropical Diseases, vol. 4, no. 10, Article ID e836, 2010.
[13]
A. T. Peterson, “Biogeography of diseases: a framework for analysis,” Naturwissenschaften, vol. 95, no. 6, pp. 483–491, 2008.
[14]
Centers for Disease Control and Prevention, “Travel-associated Dengue infections—United States, 2001–2004,” Morbidity and Mortality Weekly Report, vol. 54, no. 22, pp. 556–558, 2005.
[15]
US Department of Commerce and International Trade Administration, http://tinet.ita.doc.gov/view/m-2007-O-001/index.html, 2010.
[16]
K. Standish, G. Kuan, W. Avilés, A. Balmaseda, and E. Harris, “High dengue case capture rate in four years of a cohort study in Nicaragua compared to national surveillance data,” PLoS Neglected Tropical Diseases, vol. 4, no. 3, Article ID e633, 2010.
[17]
Centers for Disease Control and Perevention Dengue Branch (CDCDB), http://www.cdc.gov/Dengue/about/index.html, 2010.
[18]
World Health Organization (WHO)-Regional Offices, http://www.who.int/about/regions/en/index.html, 2010.
[19]
A. Moffett, N. Shackelford, and S. Sarkar, “Malaria in Africa: vector species' niche models and relative risk maps,” PLoS ONE, vol. 2, no. 9, Article ID e824, 2007.
[20]
J. G. Rigau-Pérez, D. J. Gubler, A. V. Vorndam, and G. G. Clark, “Dengue: a literature review and case study of travelers from the United States, 1986–1994,” Journal of Travel Medicine, vol. 4, no. 2, pp. 65–71, 1997.
[21]
U.S. Department of Transportation's Research and Innovative Technology Administration (RITA), http://www.rita.dot.gov/about_rita/, 2010.
[22]
Eurostat: European Commission Statistics Database, http://epp.eurostat.ec.europa.eu/portal/page/portal/eurostat/home, 2010.
[23]
C. R. Margules and S. Sarkar, Systematic Conservation Planning, Cambridge University Press, Cambridge, UK, 2007.
[24]
J. Franklin, Mapping Species Distributions: Spatial Inference and Prediction, Cambridge University Press, Cambridge, UK, 2009.
[25]
S. J. Phillips and M. Dudík, “Modeling of species distributions with Maxent: new extensions and a comprehensive evaluation,” Ecography, vol. 31, no. 2, pp. 161–175, 2008.
[26]
J. Elith, C. H. Graham, R. P. Anderson et al., “Novel methods improve prediction of species' distributions from occurrence data,” Ecography, vol. 29, no. 2, pp. 129–151, 2006.
[27]
A. Moffett, S. Strutz, N. Guda et al., “A global public database of disease vector and reservoir distributions,” PLoS Neglected Tropical Diseases, vol. 3, no. 3, Article ID e378, 2009.
R. J. Hijmans, S. E. Cameron, J. L. Parra, P. G. Jones, and A. Jarvis, “Very high resolution interpolated climate surfaces for global land areas,” International Journal of Climatology, vol. 25, no. 15, pp. 1965–1978, 2005.
[30]
E. Massad and A. Wilder-Smith, “Risk estimates of dengue in travelers to dengue endemic areas using mathematical models,” Journal of Travel Medicine, vol. 16, no. 3, pp. 191–193, 2009.
[31]
C. T. Code？o, P. M. Luz, and C. J. Struchiner, “Risk assessment of yellow fever urbanization in Rio de Janeiro, Brazil,” Transactions of the Royal Society of Tropical Medicine and Hygiene, vol. 98, no. 12, pp. 702–710, 2004.
[32]
Y. Bar-Yam, Dynamics of complex systems. Chapter 2, section 3, Addison-Wesley, Reading, Mass, USA, 1997.
[33]
O. Wichmann, N. Mühlberger, and T. Jelinek, “Dengue - The underestimated risk in travellers,” Dengue Bulletin, vol. 27, pp. 126–137, 2003.
[34]
Federal Aviation Administration: Passenger Boarding (Enplanement) and All-Cargo Data for U.S. Airports, http://www.faa.gov/airports/planning_capacity/passenger_allcargo_stats/passenger/, 2010.
