Figure 1. Dispersion of listeriosis cases, New York State (excluding New York City), November 1996–June 2000. Comparison of New York State population base overlaid with temporal listeriosis clusters from Table 1 (indicated by letter; defined by ribotype and pulsed-field gel electrophoresis type). Cases per county and annualized rate per 100,000 (in parentheses) are shown. New York City listeriosis data are not included in this study.