title: Shifts in the spatiotemporal dynamics of schistosomiasis: a case study in Anhui Province, China.
abstract: BACKGROUND
  The Chinese national surveillance system showed that the risk of Schistosoma japonicum infection fluctuated temporally. This dynamical change might indicate periodicity of the disease, and its understanding could significantly improve targeted interventions to reduce the burden of schistosomiasis. The goal of this study was to investigate how the schistosomiasis risk varied temporally and spatially in recent years.
  
  
  RESULTS
  Parasitological data were obtained through repeated cross-sectional surveys that were carried out during 1997-2010 in Anhui Province, East China. A multivariate autoregressive model, combined with principal oscillation pattern (POP) analysis, was used to evaluate the spatio-temporal variation of schistosomiasis risk. Results showed that the temporal changes of schistosomiasis risk in the study area could be decomposed into two sustained damped oscillatory modes with estimated period of approximately 2.5 years. The POPs associated with these oscillatory components showed that the pattern near the Yangtze River varied markedly and that the disease risk appeared to evolve in a Southwest/Northeast orientation. The POP coefficients showed decreasing tendency until 2001, then increasing during 2002-2005 and decaying afterwards.
  
  
  CONCLUSIONS
  The POP analysis characterized the variations of schistosomiasis risk over space and time and demonstrated that the disease mainly varied temporally along the Yangtze River. The schistosomiasis risk declined periodically with a temporal fluctuation. Whether it resulted from previous national control strategies on schistosomiasis needs further investigations.
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China; Laboratory for Spatial Analysis and Modeling, School of Public Health, Fudan University, Shanghai, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China; Laboratory for Spatial Analysis and Modeling, School of Public Health, Fudan University, Shanghai, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.affiliation: School of Epidemiology, Public Health and Preventive Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Anhui Institute of Parasitic Diseases, Wuhu, China.
authors.forename: Fenghua
authors.initials: F
authors.lastname: Gao
authors.affiliation: Anhui Institute of Parasitic Diseases, Wuhu, China.
authors.forename: Qizhi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Anhui Institute of Parasitic Diseases, Wuhu, China.
authors.forename: Shiqing
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China; Laboratory for Spatial Analysis and Modeling, School of Public Health, Fudan University, Shanghai, China; Biomedical Statistical Center, Fudan University, Shanghai, China.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China; Laboratory for Spatial Analysis and Modeling, School of Public Health, Fudan University, Shanghai, China.
authors.forename: Qingwu
authors.initials: Q
authors.lastname: Jiang
mesh_terms: D000818:Animals; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D006801:Humans; D011157:Population Dynamics; D011159:Population Surveillance; D045483:Rivers; D012549:Schistosoma japonicum; D012554:Schistosomiasis japonica / Q000453:epidemiology*