Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Data from an outbreak (August to October, 2002) of West Nile virus (WNV) encephalomyelitis in a population of
horses located in northern Indiana was scanned for clusters in time and space. One significant (
p
= 0.04) cluster
of case premises was detected, occurring between September 4 and 10 in the south-west part of the study area
(85.70°N, 45.50°W). It included 10 case premises (3.67 case premises expected) within a radius of 2264 m. Image
data were acquired by the Advanced Very High Resolution Radiometer (AVHRR) sensor onboard a National
Oceanic and Atmospheric Administration polar-orbiting satellite. The Normalized Difference Vegetation Index
(NDVI) was calculated from visible and near-infrared data of daily observations, which were composited to produce
a weekly-1km
2
resolution raster image product. During the epidemic, a significant (
p
< 0.01) decrease (0.025
per week) in estimated NDVI was observed at all case and control premise sites. The median estimated NDVI
(0.659) for case premises within the cluster identified was significantly (
p
< 0.01) greater than the median estimated
NDVI for other case (0.571) and control (0.596) premises during the same period. The difference in median
estimated NDVI for case premises within this cluster, compared to cases not included in this cluster, was greatest
(5.3% and 5.1%, respectively) at 1 and 5 weeks preceding occurrence of the cluster. The NDVI may be useful
for identifying foci of WNV transmission.
Vector-Borne Zoonotic Dis. 5, 181-188.