Fig. 1

Surveillance for I. scapularis and associated human LD cases in Canada and the US. Occurrence of blacklegged tick populations detected in active field surveillance in central and eastern Canada from 2003 to 2012 are shown in panel a, reproduced with permission from [73]: the scale indicates the percent of sites positive for I. scapularis. The occurrence of human LD cases identified in enhanced surveillance in Canada from 2009 to 2012 are shown in panel b (reproduced unchanged from [13]), noting that locations of acquisition of cases in the province of Quebec are not available. MB = Manitoba, ON = Ontario, QC = Quebec, NB = New Brunswick, NS = Nova Scotia. Occurrence of US counties with I. scapularis in a summary of tick surveillance data from the US (using the data in [58]) is shown in panel c. This map shows the evolution of I. scapularis populations in the US from data compiled in 1999 and in 2016. Red and orange fill indicates counties that were considered, respectively, as having “established” or “reported” I. scapularis in 1999 (see [58] for the definitions). Green and yellow fill respectively indicate counties that changed from no records to established or from reported to established by 2016. The occurrence of LD cases reported in national surveillance in the US (by county of residence) is shown in panel d (reproduced from [47])