Worst States for Lyme Disease

The humidity in the spring and summer seasons in Washington, D.C., provides ideal conditions for ticks — particularly deer ticks that carry Lyme disease. Based on the number of infections reported between 2016 and 2018, there are an average of 8.9 cases of Lyme disease in Washington D.C. annually for every 100,000 residents, a higher incidence rate than in all but 14 states.

Even in urban areas, disease carrying ticks can live in backyards and parks. While in much of the country Lyme disease is spread by deer populations who then pass the disease on to ticks, in urban areas like Washington, the disease is likely passed to ticks mostly by mice.

There are an average of 10.9 cases of Lyme disease for every 100,000 people in Virginia annually. The average annual incidence rate only accounts for confirmed cases and does not include probably cases, which numbered nearly 400 in 2018. Not all cases of Lyme disease are confirmed by lab tests, as testing for the infection is done by checking for antibodies for the disease, which can take several weeks after the initial infection to develop.

New York state ranks among the worst places in the country for Lyme disease. There are an average of 14.5 cases of the disease for every 100,000 people in the state annually. Lyme disease used to be more of a problem in southern parts of the state, including the lower Hudson Valley and Long Island. In recent years, however, the disease has been moving farther north, into central New York and the Adirondack region.

Over the last three years, there has been an average of 18.6 confirmed cases of Lyme disease for every 100,000 people in Maryland annually. While the incidence of the infection is higher than in most of the country, infections have become less common in recent years. There were only 14.8 cases for every 100,000 people in 2018, down from 19.7 in 2017 and 21.2 in 2016. Over the last decade of data, the worst year for Lyme disease in the state was 2009, when there were 25.7 new infections for every 100,000 residents.

Lyme disease tends to be more common in Northeastern and mid-Atlantic states, but Minnesota is one of a few Midwestern states with a near nation-leading incidence rate of the infection. There are an average of 21.9 new infections for every 100,000 people in the state annually, more than double the average infection rate nationwide of 8.1 per 100,000.

Minnesota residents are more likely to contract Lyme disease than most Americans and are also more likely to be able to seek and afford treatment. Minnesota is one of only seven states where less than than 5% of the population is without health insurance.

Lyme disease has become much more common in West Virginia in recent years. As recently as 2012, there were only 4.4 cases for every 100,000 people. As of 2018, there were 30.7 confirmed cases of the disease for every 100,000 state residents — a nearly 600% increase.

Deer tick populations, which carry Lyme disease, have grown in West Virginia in recent years. In March 2018, Gov. Jim Justice signed legislation that prevents insurance companies from denying coverage for Lyme disease treatment and care.

Wisconsin is the only state in the Midwest and one of nine states nationwide with an average of more than 25 new cases of Lyme disease for every 100,000 people annually. Infections have become less common in the state recently, as there were only 19.3 cases for every 100,000 people in 2018, down 38% from 31.0 cases per 100,000 people in 2017.

People who spend more time outdoors are at increased risk of being bitten and infected by disease-carrying ticks. In Wisconsin, nearly 80% of adults are regularly physically active, a larger share than in the majority of states.

Lyme disease was first identified in Connecticut in the 1970s, and today, the state remains one of the hotspots for the disease. There are 36.2 new infections for every 100,000 people annually in Connecticut, more than four times the national incidence rate of 8.1 new infections per 100,000.

Encouragingly, cases of the disease are becoming less common in the state. There were only 35.5 cases for every 100,000 people in 2018, down 55% from a 10-year high of 78.2 cases per 100,000 in 2009. However, experts warn that tick populations may surge this year in the state due to the mild winter and cool spring.

The humidity common in much of the mid-Atlantic region allows tick populations to thrive. In New Jersey, nearly 2,900 people were infected with Lyme disease by deer ticks, and an additional 1,100 people were likely infected. Over the last three years, there has been an average of 36.6 confirmed cases of Lyme disease for every 100,000 people in the state annually, well above the comparable 8.1 per 100,000 national average.

Confirmed cases of Lyme disease have climbed in recent years in Delaware. There were 505 confirmed cases in the state in 2018 alone, or 52.2 infections for every 100,000 people — a 19% increase from the previous year. Still, the incidence rate lags well behind the highs recorded in the state from 2009 to 2011, when Delaware led the nation in Lyme disease incidence rates.

Though cases of the infection have been identified in each of the state’s three counties, cases tend to be concentrated in New Castle, the state’s northernmost county that sits across the Delaware River from New Jersey and shares a border with Maryland and Pennsylvania — three other states that rank on this list.

The northeastern United States — particularly the New England region — is a hotspot for Lyme disease. Each of the five states with an annual incidence rate of more than 50 cases of the disease for every 100,000 people is located in the Northeast, and Rhode Island is one of them.

Cases have climbed considerably in Rhode Island over the last 10 years, from just 14.2 cases per 100,000 people in 2009 to 62.5 per 100,000 in 2018. It is important to note that the most recent incidence rate only includes the 661 confirmed cases in the state and not the additional 450 probable cases.

Every year from 2009 through 2013, New Hampshire ranked among the three states with highest concentration of new Lyme disease cases. Over the last three years, there has been an average of 63.8 cases for every 100,000 people annually, the fourth highest average among states. In 2018, the most recent year of data, there were 68.3 cases for every 100,000 people, the second most of any state, trailing only Maine, New Hampshire’s neighbor to the east.

Of the states with the highest incidence of Lyme disease, Pennsylvania is the only one located outside of the New England region. There were an average of 68.1 new Lyme cases annually in the state for every 100,000 residents between 2016 and 2018.

The type of tick that carries Lyme disease was virtually non-existent in Pennsylvania as recently as the 1960s. Experts attribute its prevalence today to climate change, change in human and animal behavior that may bring ticks closer to population centers, and the regrowth of timber that was initially cut around 1900 that is now providing a habitat for tick populations.

Over the last 30 years, cases of Lyme disease have skyrocketed in Vermont. In the early 1990s, there were fewer than a dozen cases a year. As of 2018, there were 348 confirmed cases and another 228 likely cases. Though the number of cases fluctuates from year to year, there are currently an average of 79.1 cases for every 100,000 people in the state annually.

Though Vermonters have been diagnosed with Lyme disease in every county in the state, the disease tends to be concentrated in the southern half of the state — particularly in Bennington, Rutland, and Windham counties.

Maine’s annual incidence of Lyme disease of 92 per 100,000 residents is the highest of any state and more than 10 times higher than the nationwide incidence rate of 8.1 cases per 100,000 people.

Maine is one of the most rural and sparsely populated states in the country, and Mainers are likely to be close to grassy and wooded areas where disease-carrying blacklegged ticks tend to live. According to the Maine Center for Disease Control and Prevention, Lyme disease is common in every part of the state, and children ages 5 to 14 are at especially high risk for the disease.