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Volume 17, Number 8—August 2011
Research

Early Warning System for West Nile Virus Risk Areas, California, USA

Ryan M. Carney1Comments to Author , Sean C. Ahearn, Alan McConchie2, Carol A. Glaser, Cynthia Jean, Chris Barker, Bborie Park, Kerry Padgett, Erin Parker, Ervic Aquino, and Vicki L. Kramer
Author affiliations: Author affiliations: California Department of Public Health, Richmond, California, USA (R.M. Carney, C. Glaser, C. Jean, K. Padgett, E. Parker, E. Aquino); City University of New York, New York, New York, USA (S.C. Ahearn, A. McConchie); University of California, Davis, California, USA (C. Barker, B. Park); California Department of Public Health, Sacramento, California, USA (V. Kramer)

Main Article

Figure 2

Schematic of the Dynamic Continuous-Area Space-Time (DYCAST) procedure, illustrating domains of Knox test (16,17) implemented at the center of an individual ≈0.44 km2 grid cell. The 2.4-km (1.5-mi) radius of the spatial domain represents twice the daily feeding distance (14) of Culex spp. mosquitoes in California (18) and is equivalent to the effective flight range of these vectors (19,20). The 21-day temporal domain accounts for the extrinsic incubation period of West Nile virus (21) and 2 avia

Figure 2. Schematic of the Dynamic Continuous-Area Space-Time (DYCAST) procedure, illustrating domains of Knox test (16,17) implemented at the center of an individual ≈0.44 km2 grid cell. The 2.4-km (1.5-mi) radius of the spatial domain represents twice the daily feeding distance (14) of Culex spp. mosquitoes in California (18) and is equivalent to the effective flight range of these vectors (19,20). The 21-day temporal domain accounts for the extrinsic incubation period of West Nile virus (21) and 2 avian infection cycles of 7 days each (5,14,22). These bounds define the spatiotemporal domain, within which reports of dead birds (asterisks) are evaluated for proximity in space (0.40 km) and time (3 days) (small white cylinder). Statistical significance of dead bird report pairing is assessed by using random simulations (p<0.1) (15). Procedure is repeated at other cell centers to create a continuous surface of risk.

Main Article

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Main Article

1Current affiliation: Brown University, Providence, Rhode Island, USA.

2Current affiliation: University of British Columbia, Vancouver, British Columbia, Canada.

Page created: August 15, 2011
Page updated: August 15, 2011
Page reviewed: August 15, 2011
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