Lyme Disease Statistics by State

Lyme disease is transmitted by the bite of an infected blacklegged tick, can cause joint pain, fever, and kidney complications in dogs, and is far more common in some parts of the country than others. The Companion Animal Parasite Council (CAPC) tracks real antibody test results from veterinary clinics nationwide and publishes them as a continuously updated map, broken down by state.

The figures below reflect CAPC's live data as of August 2026: more than 9 million canine Lyme disease antibody tests run so far this year, with results aggregated state by state. Because 2026 isn't over yet, these are year-to-date totals, not final annual figures.

Canine Lyme Disease Positivity Rate by State

Like its heartworm data, the Companion Animal Parasite Council (CAPC) aggregates real canine Lyme disease antibody test results from veterinary clinics and labs nationwide — over 9 million tests so far in 2026 — and publishes them as a live, continuously updated map, broken down by state.

The Lyme Belt

Ten states dominate the top of the list, and they form a very different geographic cluster than heartworm's Southern belt: West Virginia (16.98%), Vermont (11.99%), Maine (11.47%), New Hampshire (10.07%), Connecticut (9.77%), Massachusetts (8.67%), Pennsylvania (8.58%), Rhode Island (8.40%), New York (7.72%), and Wisconsin (6.47%) — all Northeast or Upper Midwest states. West Virginia's rate of 16.98% is roughly 74 times higher than Oklahoma's 0.23%, the lowest in the country. This tracks the known range of the blacklegged tick (Ixodes scapularis), Lyme disease's primary vector in the eastern US, which is most established in the Northeast and Upper Midwest.

Heartworm vs. Lyme: Opposite Geographic Patterns

It's worth comparing this map to our heartworm statistics by state page: the two diseases have almost inverse geographic footprints. States near the top of the heartworm list (Mississippi, Louisiana, Arkansas, Alabama, Texas) rank near the bottom for Lyme, and vice versa. A dog's real regional parasite risk profile depends on which disease you're asking about, not a single national risk level.

What This Data Does and Doesn't Show

These are positivity rates among dogs that were tested, not the infection rate across each state's full dog population. Testing patterns vary by region and veterinary practice, so a state's true population-wide rate could differ from its tested-positivity rate. This is still the most current, largest-scale, real-world signal available, since it's built from actual lab results rather than modeled estimates.

For general national pet health statistics, see our pet health statistics page.

The Big Picture

Lyme disease risk in US dogs is sharply regional and concentrated in the Northeast and Upper Midwest — almost the mirror image of heartworm's Southern concentration. A dog in West Virginia tests positive at roughly 74 times the rate of a dog in Oklahoma. That gap tracks the range of the blacklegged tick closely, and CAPC's longer-term maps have shown that range gradually expanding westward and southward over time, which is why regional risk should be treated as a moving target rather than a fixed map.