Location of active transmission sites of Schistosoma japonicum in lake and marshland regions in China.
Schistosomiasis control in China has, in general, been very successful during the past several decades. However, the rebounding of the epidemic situation in some areas in recent years raises concerns about a sustainable control strategy of which locating active transmission sites (ATS) is a necessary first step. This study presents a systematic approach for locating schistosomiasis ATS by combining the approaches of identifying high risk regions for schisotosmiasis and extracting snail habitats. Environmental, topographical, and human behavioural factors were included in the model. Four significant high-risk regions were detected and 6 ATS were located. We used the normalized difference water index (NDWI) combined with the normalized difference vegetation index (NDVI) to extract snail habitats, and the pointwise 'P-value surface' approach to test statistical significance of predicted disease risk. We found complicated non-linear relationships between predictors and schistosomiasis risk, which might result in serious biases if data were not properly treated. We also found that the associations were related to spatial scales, indicating that a well-designed series of studies were needed to relate the disease risk with predictors across various study scales. Our approach provides a useful tool, especially in the field of vector-borne or environment-related diseases.
Department of Epidemiology, School of Public Health, Fudan University, No. 138 Yi Xue Yuan Road, Shanghai 200032, China. zhj_zhang@fudan.edu.cn
Z J
ZJ
Zhang
T E
TE
Carpenter
H S
HS
Lynn
Y
Y
Chen
R
R
Bivand
A B
AB
Clark
F M
FM
Hui
W X
WX
Peng
Y B
YB
Zhou
G M
GM
Zhao
Q W
QW
Jiang
D000818:Animals; D002681:China / Q000453:epidemiology; D004199:Disease Vectors; D017753:Ecosystem; D005618:Fresh Water / Q000469:parasitology*; D040362:Geographic Information Systems; D006801:Humans; D008954:Models, Biological; D017215:Satellite Communications; D012549:Schistosoma japonicum / Q000302:isolation & purification; D012554:Schistosomiasis japonica / Q000469:parasitology / Q000635:transmission*; D012908:Snails / Q000254:growth & development / Q000469:parasitology* / Q000502:physiology*