Tick-borne illness

Babesiosis

Babesiosis is a malaria-like parasitic infection of red blood cells (Babesia microti) carried by black-legged ticks in the Northeast and Upper Midwest.

Continental risk map
Where Babesiosis hits hardest
H3 hexagon heatmap of 12,996 reported cases across 51 states.
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State-by-state cases

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Alaska — no CDC-reported casesAKMaine — 643 casesMEVermont — 142 casesVTNew Hampshire — 280 casesNHWashington — 3 casesWAIdaho — no CDC-reported casesIDMontana — no CDC-reported casesMTNorth Dakota — 2 casesNDMinnesota — 269 casesMNWisconsin — 392 casesWIMichigan — 8 casesMINew York — 3,605 casesNYMassachusetts — 3,471 casesMAOregon — 17 casesORNevada — no CDC-reported casesNVWyoming — no CDC-reported casesWYSouth Dakota — 1 caseSDIowa — 4 casesIAIllinois — 10 casesILIndiana — 3 casesINOhio — 14 casesOHPennsylvania — no CDC-reported casesPANew Jersey — 1,323 casesNJConnecticut — 1,610 casesCTCalifornia — 18 casesCAUtah — 2 casesUTColorado — no CDC-reported casesCONebraska — 1 caseNEMissouri — 7 casesMOKentucky — 1 caseKYWest Virginia — 2 casesWVVirginia — 10 casesVAMaryland — 41 casesMDDelaware — 18 casesDERhode Island — 990 casesRIArizona — no CDC-reported casesAZNew Mexico — no CDC-reported casesNMKansas — no CDC-reported casesKSArkansas — 5 casesARTennessee — 6 casesTNNorth Carolina — no CDC-reported casesNCSouth Carolina — 5 casesSCDistrict of Columbia — 2 casesDCHawaii — no CDC-reported casesHIOklahoma — no CDC-reported casesOKLouisiana — 5 casesLAMississippi — no CDC-reported casesMSAlabama — 1 caseALGeorgia — 2 casesGATexas — 10 casesTXFlorida — 73 casesFLCASES · PER STATE
none
most cases

12,996 reported cases across 51 states.

Top 8 states
#NameCases
1New York3,605
2Massachusetts3,471
3Connecticut1,610
4New Jersey1,323
5Rhode Island990
6Maine643
7Wisconsin392
8New Hampshire280
JFMAMJJASOND

Cases peak in July — about 2,563 cases reported.

MonthCases
Jan41
Feb22
Mar42
Apr57
May297
Jun1,544
Jul2,563
Aug1,143
Sep326
Oct198
Nov146
Dec70

Year-over-year

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8,7556,5664,3782,189020192022REPORTED CASES · PER YEAR

Ticks that carry it

2 known
TickScientific nameOne-liner
Blacklegged tickIxodes scapularisThe black-legged tick is the primary US vector of Lyme disease, established across the Northeast, Upper Midwest, and Mid-Atlantic.
Castor bean tickIxodes ricinusThe castor bean tick is the principal European vector of Lyme borreliosis and tick-borne encephalitis, ranging from Britain to the Caspian.

Pathogens that cause it

1 known
PathogenScientific nameOne-liner
Babesia microtiBabesia microtiMalaria-like protozoan that infects red blood cells; the dominant cause of human babesiosis in the northeastern and upper-midwest US.

Wild facts

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