Blacklegged Tick Distribution in U.S. Counties (1998-2016)
Comparing the spread of blacklegged ticks across U.S. counties
Counties with Blacklegged Ticks in 1998
30%
of U.S. counties
Counties with Blacklegged Ticks in 2016
45.7%
of U.S. counties
Established Tick Counties in 1998
396
counties
Established Tick Counties in 2016
842
counties
County Distribution Status
Percent of Counties with Ticks
Comparison of Established Blacklegged Tick Counties
1998
2016
No Records
Reported (fewer than 6 ticks)
Established (6+ ticks or multiple life stages)
Regional Distribution of Blacklegged Ticks
Regional Expansion of Blacklegged Ticks (1998-2016)
Low Expansion
Moderate Expansion
High Expansion
Very High Expansion
*A county is classified as "established" if it has at least six individual ticks of a single life stage or at least two life stages detected in the county.
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Compare geographical patterns between 1998 and 2016