Spatial risk assessments based on vector-borne disease epidemiologic data: importance of scale for West Nile virus disease in Colorado.
We used epidemiologic data for human West Nile virus (WNV) disease in Colorado from 2003 and 2007 to determine 1) the degree to which estimates of vector-borne disease occurrence is influenced by spatial scale of data aggregation (county versus census tract), and 2) the extent of concordance between spatial risk patterns based on case counts versus incidence. Statistical analyses showed that county, compared with census tract, accounted for approximately 50% of the overall variance in WNV disease incidence, and approximately 33% for the subset of cases classified as West Nile neuroinvasive disease. These findings indicate that sub-county scale presentation provides valuable risk information for stakeholders. There was high concordance between spatial patterns of WNV disease incidence and case counts for census tract (83%) but not for county (50%) or zip code (31%). We discuss how these findings impact on practices to develop spatial epidemiologic data for vector-borne diseases and present data to stakeholders.
Winters
Anna M
AM
Division of Vector-Borne Infectious Diseases, National Center for Vector-Borne, Zoonotic and Enteric Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
Eisen
Rebecca J
RJ
Delorey
Mark J
MJ
Fischer
Marc
M
Nasci
Roger S
RS
Zielinski-Gutierrez
Emily
E
Moore
Chester G
CG
Pape
W John
WJ
Eisen
Lars
L
D000818:Animals; D003120:Colorado / Q000453:epidemiology; D009033:Culicidae; D004196:Disease Outbreaks; D040362:Geographic Information Systems; D005843:Geography; D006801:Humans; D007303:Insect Vectors; D008954:Models, Biological; D011159:Population Surveillance; D018570:Risk Assessment; D012307:Risk Factors; D014901:West Nile Fever / Q000453:epidemiology* / Q000821:virology