At a glance
Tick surveillance and pathogen surveillance data sets used to develop tick surveillance data dashboards.
![Photo of a magnifying glass with charts on a table.](/ticks/media/images/2024/05/magnifying-glass.png)
Blacklegged tick (Ixodes scapularis) and western blacklegged tick (Ixodes pacificus) by county in the contiguous United States
- Counties classified as "established" are those where six or more ticks of a single life stage or more than one life stage of the tick were collected in the county within a 12-month period.
- Counties classified as "reported" are those where less than six ticks of a single life stage were collected in the county within a 12-month period.
- Counties classified as "no records" should not be interpreted as the tick being absent. No records could be a result of a lack of sampling efforts, tick collections, or a lack of reporting or publishing the results of sampling efforts.
- County status is cumulative. Once a tick species is recorded as "established" within a county, the status will remain "established" in subsequent years.
Established and reported records of I. pacificus and I. scapularis through Dec. 31, 2023
Tickborne pathogens identified in host-seeking blacklegged and western blacklegged (Ixodes species) ticks: status by county in the United States
- 2023 Update: Pathogens included in dataset:
- Borrelia burgdorferi sensu stricto
- Borrelia mayonii
- Borrelia miyamotoi
- Anaplasma phagocytophilum human active variant
- Ehrlichia muris eauclairensis
- Babesia microti
- Powassan virus
- Borrelia burgdorferi sensu stricto
- Counties classified as "present" are those where indicated tickborne pathogens have been identified in one or more host-seeking Ixodes scapularis or Ixodes pacificus ticks, using pathogen species-specific molecular methods.
- Counties classified as "no records" should not be interpreted as the pathogen being absent. No records could be a result of a lack of sampling efforts, tick collections, pathogen testing in collected ticks, or a lack of reporting or publishing the results of sampling efforts.
- County status for tickborne pathogens is cumulative. Once a pathogen has been identified in host-seeking ticks within a county and recorded as "present", the status will remain "present" in subsequent years.