Water Quality, Exposure and Health

, Volume 4, Issue 3, pp 159–168 | Cite as

Modeling the Combined Influence of Host Dispersal and Waterborne Fate and Transport on Pathogen Spread in Complex Landscapes

  • Adam N. AkullianEmail author
  • Ding Lu
  • Julia Z. McDowell
  • George M. Davis
  • Robert C. Spear
  • Justin V. Remais
Original Paper


Environmental models, often applied to questions on the fate and transport of chemical hazards, have recently become important in tracing certain environmental pathogens to their upstream sources of contamination. These tools, such as first-order decay models applied to contaminants in surface waters, offer promise for quantifying the fate and transport of pathogens with multiple environmental stages and/or multiple hosts, in addition to those pathogens whose environmental stages are entirely waterborne. Here we consider the fate and transport capabilities of the human schistosome Schistosoma japonicum, which exhibits two waterborne stages and is carried by an amphibious intermediate snail host. We present experimentally derived dispersal estimates for the intermediate snail host and fate and transport estimates for the passive downstream diffusion of cercariae, the waterborne, human-infective parasite stage. Using a one-dimensional advective transport model exhibiting first-order decay, we simulate the added spatial reach and relative increase in cercarial concentrations that dispersing snail hosts contribute to downstream sites. Simulation results suggest that snail dispersal can substantially increase the concentrations of cercariae reaching downstream locations, relative to no snail dispersal, effectively putting otherwise isolated downstream sites at increased risk of exposure to cercariae from upstream sources. The models developed here can be applied to other infectious diseases with multiple life-stages and hosts, and have important implications for targeted ecological control of disease spread.


Infectious disease Schistosoma japonicum Fate and transport Migration Dispersal Spatial spread Environment Public health 



This work was supported in part by the NSF/NIH Ecology of Infectious Disease Program (grant 0622743), by the National Institute for Allergy and Infectious Disease (grant nos. K01AI091864 and R01AI068854), and by the Emory University Global Health Institute Faculty Distinction Fund. The authors wish to thank our colleagues at the Sichuan Centers for Disease Control and Prevention (Chengdu, People’s Republic of China), and our colleagues at the Anxian, Zhongjiang and Jinyang County Anti-Schistosomiasis Stations for their continued support and collaboration. We would also like to thank Yiliu Chen for her contributions to the cercarial transport model and Kenneth Bencala for providing expert advice on modeling hydrological transport processes.


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Adam N. Akullian
    • 1
    Email author
  • Ding Lu
    • 2
  • Julia Z. McDowell
    • 3
  • George M. Davis
    • 4
  • Robert C. Spear
    • 5
  • Justin V. Remais
    • 3
  1. 1.School of Public Health and Community Medicine, Department of EpidemiologyUniversity of WashingtonSeattleUSA
  2. 2.Institute of Parasitic DiseaseSichuan Provincial Center for Disease Control and PreventionChengduPeople’s Republic of China
  3. 3.Department of Environmental Health, Rollins School of Public HealthEmory UniversityAtlantaUSA
  4. 4.Department of Microbiology and Tropical MedicineGeorge Washington University Medical CenterWashingtonUSA
  5. 5.Center for Occupational and Environmental Health, School of Public HealthUniversity of California, BerkeleyBerkeleyUSA

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