title: Global malaria connectivity through air travel.
abstract: BACKGROUND
  Air travel has expanded at an unprecedented rate and continues to do so. Its effects have been seen on malaria in rates of imported cases, local outbreaks in non-endemic areas and the global spread of drug resistance. With elimination and global eradication back on the agenda, changing levels and compositions of imported malaria in malaria-free countries, and the threat of artemisinin resistance spreading from Southeast Asia, there is a need to better understand how the modern flow of air passengers connects each Plasmodium falciparum- and Plasmodium vivax-endemic region to the rest of the world.
  
  
  METHODS
  Recently constructed global P. falciparum and P.vivax malaria risk maps, along with data on flight schedules and modelled passenger flows across the air network, were combined to describe and quantify global malaria connectivity through air travel. Network analysis approaches were then utilized to describe and quantify the patterns that exist in passenger flows weighted by malaria prevalence. Finally, the connectivity within and to the Southeast Asia region where the threat of imported artemisinin resistance arising is highest, was examined to highlight risk routes for its spread.
  
  
  RESULTS
  The analyses demonstrate the substantial connectivity that now exists between and from malaria-endemic regions through air travel. While the air network provides connections to previously isolated malarious regions, it is clear that great variations exist, with significant regional communities of airports connected by higher rates of flow standing out. The structures of these communities are often not geographically coherent, with historical, economic and cultural ties evident, and variations between P. falciparum and P. vivax clear. Moreover, results highlight how well connected the malaria-endemic areas of Africa are now to Southeast Asia, illustrating the many possible routes that artemisinin-resistant strains could take.
  
  
  CONCLUSIONS
  The continuing growth in air travel is playing an important role in the global epidemiology of malaria, with the endemic world becoming increasingly connected to both malaria-free areas and other endemic regions. The research presented here provides an initial effort to quantify and analyse the connectivity that exists across the malaria-endemic world through air travel, and provide a basic assessment of the risks it results in for movement of infections.
authors.affiliation: Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA. seenhzj@gmail.com.
authors.forename: Zhuojie
authors.initials: Z
authors.lastname: Huang
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tatem
mesh_terms: D064870:Air Travel; D003198:Computer Simulation; D014943:Global Health; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000635:transmission*; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000635:transmission*
references.citation: Int J Health Geogr. 2012 Aug 14;11:33
references.pmid: 22892045
references.citation: Nat Rev Microbiol. 2010 Apr;8(4):272-80
references.pmid: 20208550
references.citation: Am J Trop Med Hyg. 2001 Jan-Feb;64(1-2 Suppl):12-7
references.pmid: 11425173
references.citation: J Infect Dis. 2011 Dec 15;204(12):1980-8
references.pmid: 22021623
references.citation: Malar J. 2012 Apr 24;11:122
references.pmid: 22531245
references.citation: Am J Trop Med Hyg. 2012 Feb;86(2):349-58
references.pmid: 22302873
references.citation: Parasit Vectors. 2011 May 26;4:92
references.pmid: 21615906
references.citation: Lancet Infect Dis. 2012 Nov;12(11):888-96
references.pmid: 23099083
references.citation: Trends Parasitol. 2010 Sep;26(9):447-56
references.pmid: 20728060
references.citation: BMJ. 2012 Mar 27;344:e2116
references.pmid: 22454091
references.citation: Lancet Infect Dis. 2004 Jun;4(6):327-36
references.pmid: 15172341
references.citation: AIDS. 2012 Nov 28;26(18):2351-60
references.pmid: 22951637
references.citation: Euro Surveill. 2011 Oct 20;16(42):
references.pmid: 22027375
references.citation: Science. 2012 Oct 12;338(6104):267-70
references.pmid: 23066082
references.citation: BMC Infect Dis. 2010 Sep 22;10:279
references.pmid: 20860809
references.citation: Lancet. 1988 Mar 12;1(8585):586
references.pmid: 2894515
references.citation: Lancet. 2012 May 26;379(9830):1960-6
references.pmid: 22484134
references.citation: Nat Commun. 2011;2:266
references.pmid: 21468018
references.citation: Lancet Infect Dis. 2010 Aug;10(8):545-55
references.pmid: 20637696
references.citation: Sci Rep. 2011;1:93
references.pmid: 22355611
references.citation: PLoS One. 2013 May 15;8(5):e64317
references.pmid: 23691194
references.citation: Neth J Med. 2002 Dec;60(11):441-3
references.pmid: 12685493
references.citation: Malar J. 2011 Dec 20;10:378
references.pmid: 22185615
references.citation: Am J Trop Med Hyg. 2012 Aug;87(2):231-241
references.pmid: 22855752
references.citation: Proc Natl Acad Sci U S A. 2004 Mar 16;101(11):3747-52
references.pmid: 15007165
references.citation: Clin Infect Dis. 1998 Jul;27(1):142-9
references.pmid: 9675468
references.citation: MMWR Morb Mortal Wkly Rep. 2002 Oct 18;51(41):921-3
references.pmid: 12403407
references.citation: Malar J. 2009 Dec 10;8:287
references.pmid: 20003266
references.citation: Parasitol Today. 1988 May;4(5):147-50
references.pmid: 15463072
references.citation: Parasitology. 2012 Dec;139(14):1816-30
references.pmid: 22444826
references.citation: Malar J. 2012 Sep 17;11:328
references.pmid: 22985344
references.citation: Science. 2012 Nov 2;338(6107):612-4
references.pmid: 23118172
references.citation: Malar J. 2011 Nov 10;10:339
references.pmid: 22074219
references.citation: MMWR Morb Mortal Wkly Rep. 2003 Sep 26;52(38):908-11
references.pmid: 14508439
references.citation: Lancet Infect Dis. 2012 Mar;12(3):222-30
references.pmid: 22252149
references.citation: J Infect Dis. 2010 May 1;201(9):1326-30
references.pmid: 20350192
references.citation: Proc Natl Acad Sci U S A. 2010 Jul 6;107(27):12222-7
references.pmid: 20566870
references.citation: Malar J. 2011 Nov 10;10:340
references.pmid: 22074250
references.citation: Am J Emerg Med. 2012 Jul;30(6):972-80
references.pmid: 21908138
references.citation: PLoS One. 2011;6(9):e23832
references.pmid: 21912645
references.citation: Proc Natl Acad Sci U S A. 2005 May 31;102(22):7794-9
references.pmid: 15911778
references.citation: Clin Microbiol Infect. 2012 May;18(5):468-74
references.pmid: 21848975
references.citation: Bull World Health Organ. 1989;67(6):737-43
references.pmid: 2699278
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Nov;70(5 Pt 2):056131
references.pmid: 15600716
references.citation: Malar J. 2012 Jun 18;11:205
references.pmid: 22703541
references.citation: PLoS Negl Trop Dis. 2012;6(9):e1814
references.pmid: 22970336
references.citation: Malar J. 2012 Feb 21;11:52
references.pmid: 22353879
references.citation: Malar J. 2006 Jul 14;5:57
references.pmid: 16842613
references.citation: PLoS One. 2012;7(2):e31743
references.pmid: 22363717
references.citation: Science. 2013 Feb 22;339(6122):909-10
references.pmid: 23430640