Tickborne pathogen surveillance

Distribution of Lyme disease spirochetes in host-seeking Ixodes scapularis and Ixodes pacificus ticks, 2020

Map of the US showing distribution of counties where Lyme disease have been identified. Cases are concentrated in the Northeast and California and Washington state.

Reported distribution of counties where Lyme disease spirochetes have been identified.  Counties classified as “present” are those where Borrelia burgdorferi sensu stricto or Borrelia mayonii have been identified in one or more host-seeking Ixodes scapularis or Ixodes pacificus ticks, using species-specific molecular methods.

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