An early warning system for West Nile virus (WNV) outbreaks could provide a basis for targeted public education and surveillance activities as well as more timely larval and adult mosquito control. We adapted the spatial scan statistic for prospective detection of infectious disease outbreaks, applied the results to data on dead birds reported from New York City in 2000, and reviewed its utility in providing an early warning of WNV activity in 2001. Prospective geographic cluster analysis of dead bird reports may provide early warning of increasing viral activity in birds and mosquitoes, allowing jurisdictions to triage limited mosquito-collection and laboratory resources and more effectively prevent human disease caused by the virus. This adaptation of the scan statistic could also be useful in other infectious disease surveillance systems, including that for bioterrorism.

West Nile (WN) virus was found throughout New York State in 2000, with the epicenter in New York City and surrounding counties. We tested 3,403 dead birds and 9,954 mosquito pools for WN virus during the transmission season. Sixty-three avian species, representing 30 families and 14 orders, tested positive for WN virus. The highest proportion of dead birds that tested positive for WN virus was in American Crows in the epicenter (67% positive, n=907). Eight mosquito species, representing four genera, were positive for WN virus. The minimum infection rate per 1,000 mosquitoes (MIR) was highest for Culex pipiens in the epicenter: 3.53 for the entire season and 7.49 for the peak week of August 13. Staten Island had the highest MIR (11.42 for Cx. pipiens), which was associated with the highest proportion of dead American Crows that tested positive for WN virus (92%, n=48) and the highest number of human cases (n=10).

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SummaryCuticular structures of insects are often microscopic and intricately complex; among the most complex structures are male genitalia. Genitalic structures are essential in taxonomic and phylogenetic studies of insects. Using well-described species from two disparate dipteran genera, we demonstrate the utility of confocal laser scanning microscopy for studying the morphological characters of fly genitalia by taking advantage of the autofluorescent properties of cuticle material. Reconstructions of confocal data sets obtained from genitalic structures embedded in two commonly used entomological mounting media (euparal and glycerin jelly) are presented. Aberration artefacts often observed in confocal data obtained from thick specimens were analysed and strategies for their minimization are discussed. Our results indicate that confocal laser scanning microscopy and 3D reconstruction are excellent techniques for visualizing small, complex, autofluorescent structures in flies. These techniques could have a profound impact on the quality of information provided by 3D representations of insect structures over more traditional methods of visualization.