Common species in Connecticut
Connecticut follows the state health led source pattern. The species below are drawn from the state-authority sources listed in the sidebar Data Row.
- Asian longhorned tick (CT DPH + CAES surveillance; expanding)
- Lone star tick (continued northward expansion documented by CAES)
When ticks are most active
Broad caution April through October. Blacklegged tick nymphs peak May-July; adult blacklegged active spring + fall and on warm winter days. CT has the highest per-capita Lyme incidence among large U.S. states (Lyme disease is literally named for Old Lyme, Connecticut). Lone star tick activity May-August expanding.
Where you're most likely to encounter ticks
Litchfield Hills hiking, Connecticut River valley trails, Old Lyme + Connecticut shoreline (Lyme disease was first described here), Fairfield County suburban edges, Mystic + eastern CT, Bradley Mountain + state parks, dog walking in any wooded edge — CT is essentially all tick country.
Disease context
Each disease named below carries an evidence tag per the Data Row policy. Pills indicate the strength of state-specific evidence, not the severity of the disease. Symptoms should always be routed to a clinician; this is orientation, not diagnosis.
- Lyme diseasestate surveillance confirmed
Lyme is literally named for Old Lyme, CT (1975 cluster). CT consistently leads U.S. Lyme per-capita incidence; CT DPH + CAES publish county-level data
- Anaplasmosisstate surveillance confirmed
- Babesiosisstate surveillance confirmed
CT has substantial babesiosis case loads
- Powassan virus diseasestate surveillance confirmed
- Ehrlichiosisstate surveillance confirmed
- Hard tick relapsing feverstate surveillance confirmed
- Alpha-gal syndromeregional pattern
Lone star expansion makes CT a watch zone for AGS
- Rocky Mountain spotted fevernon diagnostic mention only
If you find a tick — what to do
Map resolution notes
mixed resolution.CAES Tick Office data supports county-resolution + pathogen-prevalence claims uniquely well in CT — one of the most data-rich states in the country. CT DPH publishes county-level Lyme + tickborne disease data. CDC maps support national comparison.
State sources
- Primary species source
- Connecticut Department of Public Health (CT DPH) Tickborne Diseases hub; Connecticut Agricultural Experiment Station (CAES) Tick Office (long-running CT-state-funded tick identification + research program — among the most established in the U.S.).
- Primary health source
- CT DPH Tickborne Diseases hub + CT DPH reportable disease summaries; CAES Tick Office publications and surveillance reports; CDC pages and maps for national guardrails.
- Primary extension source
- UConn Cooperative Extension + CAES Tick Office (CAES + UConn share extension publications on CT tick species, life cycle, and yard management).
- Surveillance
- CT DPH county-level Lyme + tickborne disease surveillance; CAES Tick Office maintains the longest-running U.S. state tick surveillance + testing program — county-level tick species data + pathogen prevalence data is uniquely available for CT; CDC for national comparison.