Connectivity sustains disease transmission in environments with low potential for endemicity: modelling schistosomiasis with hydrologic and social connectivities.
Social interaction and physical interconnections between populations can influence the spread of parasites. The role that these pathways play in sustaining the transmission of parasitic diseases is unclear, although increasingly realistic metapopulation models are being used to study how diseases persist in connected environments. We use a mathematical model of schistosomiasis transmission for a distributed set of heterogeneous villages to show that the transport of parasites via social (host movement) and environmental (parasite larvae movement) pathways has consequences for parasite control, spread and persistence. We find that transmission can be sustained regionally throughout a group of connected villages even when individual village conditions appear not to support endemicity. Optimum transmission is determined by an interplay between different transport pathways, and not necessarily by those that are the most dispersive (e.g. disperse social contacts may not be optimal for transmission). We show that the traditional targeting of villages with high infection, without regard to village interconnections, may not lead to optimum control. These findings have major implications for effective disease control, which needs to go beyond considering local variations in disease intensity, to also consider the degree to which populations are interconnected.
Gurarie
David
D
Department of Mathematics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44122, USA.
Seto
Edmund Y W
EY
D000818:Animals; D004777:Environment; D006790:Host-Parasite Interactions; D006801:Humans; D007398:Interpersonal Relations; D008962:Models, Theoretical; D012547:Schistosoma / Q000502:physiology; D012552:Schistosomiasis / Q000469:parasitology / Q000517:prevention & control / Q000635:transmission*; D014867:Water / Q000469:parasitology*
D014867:Water
Eur J Epidemiol. 2003;18(11):1065-72
14620941
Acta Trop. 1991 Sep;49(4):241-70
1684260
Trans R Soc Trop Med Hyg. 2002 Nov-Dec;96(6):577-9
12625126
Lancet. 1996 Nov 9;348(9037):1274-8
8909380
Science. 2006 Apr 21;312(5772):384-8
16627734
Am J Infect Control. 2005 Jun;33(5):252-7
15947741
Parasitology. 2005 Jan;130(Pt 1):49-65
15700757
Parasitol Int. 2005 Mar;54(1):83-9
15710556
Geospat Health. 2007 May;1(2):233-41
18686248
Trans R Soc Trop Med Hyg. 1996 Jul-Aug;90(4):340-6
8882173
Trans R Soc Trop Med Hyg. 1965 Sep;59(5):489-506
5860312
S Afr Med J. 1996 Apr;86(4):350-3
8693370
Acta Trop. 2000 Oct 23;77(1):41-51
10996119
Nature. 2001 Mar 29;410(6828):515-6
11279464
Am J Trop Med Hyg. 2004 Jan;70(1):48-56
14971698
J Theor Biol. 2004 Aug 7;229(3):349-59
15234202
Emerg Infect Dis. 2007 Jul;13(7):973-9
18214167
Science. 2002 Jul 26;297(5581):537-41
12142520
Bull Math Biol. 2003 Jan;65(1):1-26
12597114
JAMA. 2001 Dec 5;286(21):2711-7
11730447
Rev Inst Med Trop Sao Paulo. 2000 Jul-Aug;42(4):209-17
10968884
Trop Med Int Health. 2007 Oct;12(10):1199-209
17956502
Trans R Soc Trop Med Hyg. 1980;74(1):36-9
7434418
Proc Natl Acad Sci U S A. 2007 Apr 24;104(17):7110-5
17438266
Naturwissenschaften. 2001 Sep;88(9):372-81
11688412
Ann Soc Belg Med Trop. 1990 Sep;70(3):173-80
2122819
Trans R Soc Trop Med Hyg. 1978;72(1):6-15
635979
Lancet Infect Dis. 2006 Jul;6(7):411-25
16790382
Trends Ecol Evol. 1997 Oct;12(10):395-9
21238122
Clin Microbiol Rev. 2001 Apr;14(2):270-95
11292639