Number of ticks/Human population
Figure 2. The distribution of Ixodes scapularis submitted to provincial and federal public health agencies from January 1990 to December 2003 (grey circles that are centred on the centroid of the census sub-division from which they were submitted). Only data from individuals who had no history of recent travel out of the census sub-division are shown. Census sub-division in which resident I. scapularis populations are currently known to occur are indicated by arrows, and the CSD containing the only I. scapularis population known in 1991 is indicated by the bold arrow. The boundaries of all census sub-divisions are shown as grey lines. These data include those obtained from the Lyme Disease Association of Ontario for 1993 to 1999. Reproduced with permission from Ogden et al. 2006. J Med Entomol May, 43(3):605.
