Tickpedia
County-level presence

Where Borrelia burgdorferi has been detected

Counties with at least one positive surveillance report for Borrelia burgdorferi, aggregated to a state-level choropleth. Click any state to open its page.

Where it's been detected

pathogenCounty · status=present
Alaska — no detections on recordAKMaine — 15 countiesMEVermont — 13 countiesVTNew Hampshire — 10 countiesNHWashington — 3 countiesWAIdaho — no detections on recordIDMontana — no detections on recordMTNorth Dakota — 2 countiesNDMinnesota — 34 countiesMNWisconsin — 41 countiesWIMichigan — 40 countiesMINew York — 59 countiesNYMassachusetts — 6 countiesMAOregon — 1 countyORNevada — no detections on recordNVWyoming — no detections on recordWYSouth Dakota — 1 countySDIowa — 17 countiesIAIllinois — 51 countiesILIndiana — 88 countiesINOhio — 49 countiesOHPennsylvania — 67 countiesPANew Jersey — 20 countiesNJConnecticut — 8 countiesCTCalifornia — 29 countiesCAUtah — no detections on recordUTColorado — no detections on recordCONebraska — 1 countyNEMissouri — no detections on recordMOKentucky — 15 countiesKYWest Virginia — 26 countiesWVVirginia — 47 countiesVAMaryland — 10 countiesMDDelaware — 3 countiesDERhode Island — 1 countyRIArizona — no detections on recordAZNew Mexico — no detections on recordNMKansas — no detections on recordKSArkansas — no detections on recordARTennessee — 6 countiesTNNorth Carolina — 18 countiesNCSouth Carolina — 3 countiesSCDistrict of Columbia — 1 countyDCHawaii — no detections on recordHIOklahoma — no detections on recordOKLouisiana — 1 countyLAMississippi — no detections on recordMSAlabama — no detections on recordALGeorgia — 2 countiesGATexas — no detections on recordTXFlorida — no detections on recordFLCOUNTIES · PER STATE
none
most counties

Detected in 688 counties across 33 states.

Top 8 states
#NameCounties
1Indiana88
2Pennsylvania67
3New York59
4Illinois51
5Ohio49
6Virginia47
7Wisconsin41
8Michigan40

Spread over time

cumulative counties detected
6885163441720202320242025CUMULATIVE COUNTIES · PER YEAR