Spatio-temporal pattern of viral meningitis in Michigan, 1993-2001

To characterize Michigan’s high viral meningitis incidence rates, 8,803 cases from 1993–2001 were analyzed for standard epidemiological indices, geographic distribution, and spatio-temporal clusters. Blacks and infants were found to be high-risk groups. Annual seasonality and interannual variability in epidemic magnitude were apparent. Cases were concentrated in southern Michigan, and cumulative incidence was correlated with population density at the county level (r 1⁄4 0.45, p<0.001). Kulldorff’s Scan test identified the occurrence of spatio-temporal clusters in Lower Michigan during July–October 1998 and 2001 (p 1⁄4 0.01). More extensive data on cases, laboratory isolates, sociodemographics, and environmental exposures should improve detection and enhance the effectiveness of a SpaceTime Information System aimed at prevention.