Why Is Lyme Disease So Bad Right Now?

Tick bites are unusually high in 2026
Blacklegged ticks are established across a widening geographic range
Climate, ecology, and human exposure all contribute

Why is Lyme disease so bad right now? There is no single explanation. Lyme disease remains a major public health problem because people are encountering ticks frequently, blacklegged ticks have expanded geographically, and environmental and ecological conditions can support tick survival and human exposure.

There is also a particularly timely reason people are asking this question in 2026. The Centers for Disease Control and Prevention (CDC) reported in April that emergency department visits for tick bites were higher than normal in many parts of the United States. In every region except the South Central United States, weekly rates were the highest for that time of year since 2017.¹

By July 2026, the CDC reported that emergency department visits for tick bites were at a 10-year high in some parts of the country.²

That does not prove that 2026 will ultimately produce a record number of Lyme disease cases. But it does show that human contact with ticks has been unusually high during parts of this year’s tick season.

Lyme Disease Is Already a Large Public Health Problem

The scale of Lyme disease is much larger than the number of cases appearing in routine surveillance reports might suggest.

The CDC currently reports that more than 80,000 Lyme disease cases are reported each year by states and jurisdictions. However, an estimate based on insurance claims suggests that approximately 476,000 people may be diagnosed and treated for Lyme disease annually in the United States.³

The CDC cautions that the 476,000 estimate may include people treated based on clinical suspicion who did not actually have Lyme disease. Nevertheless, the difference illustrates an important point: reported surveillance cases and the number of people diagnosed and treated for Lyme disease are not the same thing.

Blacklegged Ticks Have Expanded Into New Areas

One of the most important long-term changes is geographic.

The blacklegged tick, Ixodes scapularis, is now widely distributed across the eastern United States. CDC surveillance maps document established populations across a broad geographic area, and research has documented substantial expansion in the Northeast, Upper Midwest, Ohio Valley, and parts of the Southeast.^4,5

A review of historical tick records found that expansion and increasing local populations of blacklegged ticks were followed by increases in Lyme disease cases in newly affected areas.⁵

This matters because Lyme disease is no longer only a concern in a small number of traditional hot spots. Patients and clinicians in areas where Lyme disease was once considered uncommon may increasingly encounter infected ticks.

Climate Is Part of the Story—but Not the Whole Story

Warmer temperatures can affect where ticks survive and how long they remain active. Adult blacklegged ticks may search for hosts whenever winter temperatures rise above freezing, according to the CDC.⁴

Climate models also project continued northward expansion of suitable habitat for Ixodes scapularis. A recent modeling study identified temperature, precipitation, moisture, growing-season length, and other environmental variables as important predictors of tick distribution.⁶

But it is too simplistic to say that climate change alone explains the rise in Lyme disease.

A review examining the spread of blacklegged ticks in the northern United States concluded that the relative contributions of climate, landscape, and host populations remain difficult to separate. The recovery and spread of white-tailed deer populations, land-use changes, reforestation, and other ecological factors have also contributed to tick expansion.⁷

In other words, warmer conditions may make some environments more favorable for ticks, but ticks also need appropriate habitat and animal hosts.

Suburban Landscapes Can Bring People and Ticks Together

Lyme disease risk is not limited to deep wilderness.

Blacklegged ticks thrive in wooded and brushy environments where they can feed on wildlife during different stages of their life cycle. Residential development near wooded areas can place people, pets, deer, rodents, and ticks in close proximity.

This creates opportunities for exposure around yards, trails, parks, gardens, and neighborhood edges—not only during hiking or camping.

As tick populations become established in more communities, everyday outdoor activity can become a meaningful source of exposure.

Tick Bites Are Easy to Miss

Another reason Lyme disease remains difficult to control is that the tick responsible for infection may never be noticed.

Nymphal blacklegged ticks are extremely small, and tick bites are often painless. A tick can attach in a difficult-to-see location and detach before the patient ever knows it was present.

That is why the absence of a remembered tick bite should not automatically exclude Lyme disease. Learn more about Lyme disease without a recognized tick bite.

The rash can also be missed. An erythema migrans rash does not always have the classic bull’s-eye appearance and may occur on an area of the body that is difficult to see. Patients without a recognized bite or obvious rash may initially present with fatigue, headache, fever, muscle or joint pain, or other nonspecific symptoms.

For a broader discussion of presentation patterns, see the Lyme disease symptoms guide.

More Tick Exposure Also Means More Opportunities for Delayed Diagnosis

An increase in tick encounters creates another challenge: not every infection is recognized immediately.

Early Lyme disease may resemble a viral illness. Antibody testing can also be negative early in infection before a detectable antibody response develops. Patients may not recall a tick bite, and the rash may be absent, unnoticed, or atypical.

These factors can contribute to delayed recognition, particularly in regions where clinicians have historically seen relatively little Lyme disease.

As the geographic range of ticks changes, clinical awareness has to change with it. The problem is not simply whether more ticks exist. It is whether patients and clinicians recognize the illness when exposure occurs.

What Should You Do About the Increasing Tick Risk?

The goal is not to avoid the outdoors. It is to recognize that tick exposure can occur in ordinary environments and to respond appropriately.

After spending time in wooded, brushy, or grassy areas, check the body carefully for ticks. Pay particular attention to the scalp, behind the ears, under the arms, around the waist, behind the knees, and other areas where ticks may be difficult to see.

If an attached tick is found, remove it promptly and carefully. The CDC recommends grasping the tick close to the skin with fine-tipped tweezers and pulling upward with steady pressure.⁸

What happens after removal depends on the circumstances of the exposure, the type of tick, attachment characteristics, symptoms, and individual clinical considerations. I discuss these decisions in What to Do After a Tick Bite: Wait or Treat?

Frequently Asked Questions

Why is Lyme disease so bad right now?

Several factors are occurring at the same time. Tick bites have been unusually high in parts of the United States in 2026, blacklegged ticks have expanded geographically, and climate, wildlife populations, land use, and human exposure all influence Lyme disease risk.

Are ticks worse in 2026?

There is evidence of unusually high tick exposure in 2026. In April, the CDC reported that emergency department visits for tick bites were the highest for that time of year since 2017 in every U.S. region except the South Central region. Later in the summer, CDC reported a 10-year high in some parts of the country. These data measure tick-bite visits, however, not final Lyme disease case totals for 2026.

Is climate change causing more Lyme disease?

Climate is one factor. Temperature, humidity, precipitation, and growing-season length can influence tick survival and geographic suitability. However, research also points to wildlife populations, reforestation, land use, habitat, and human behavior. The relative contribution of each factor varies by location and remains an active area of research.

How common is Lyme disease in the United States?

The CDC reports more than 80,000 surveillance cases annually. An insurance-claims estimate suggests approximately 476,000 people may be diagnosed and treated for Lyme disease each year, although the CDC notes that this estimate may include some patients who do not actually have Lyme disease.

Can Lyme disease occur even if I never saw a tick?

Yes. Lyme disease is transmitted by infected ticks, but the tick bite itself may never be noticed. Nymphal ticks are very small, bites may be painless, and the tick may detach before symptoms develop.

Clinical Takeaway

Lyme disease seems especially prominent right now because several trends are converging: unusually high tick encounters in parts of the United States, an expanding geographic range of blacklegged ticks, environmental and ecological changes, and continuing challenges recognizing early infection.

It is important not to attribute the increase to one factor alone. Climate influences tick habitat, but wildlife, landscape changes, human behavior, and local ecology also affect exposure.

And increased exposure makes early recognition increasingly important. A tick bite may go unnoticed, the rash may not look like a classic bull’s-eye, and early symptoms may resemble other illnesses.

The changing Lyme disease landscape is not simply about more reported cases—it is about more opportunities for people to encounter infected ticks in places and situations where they may not expect them.

Related Articles

For more on recognizing Lyme disease and understanding why diagnosis may be delayed:

First Symptoms of Lyme Disease: Why the Rash Is Often Missing
Why Lyme Disease Gets Missed, Misdiagnosed, or Dismissed
Can Lyme Disease Go Away on Its Own?

References

1. Centers for Disease Control and Prevention. CDC Data Show Weekly ER Visits for Tick Bites Higher than Usual. April 23, 2026.
2. National Institute for Occupational Safety and Health. Tick Talk: Protecting Workers From Tickborne Diseases. CDC. July 8, 2026.
3. Centers for Disease Control and Prevention. Lyme Disease Surveillance and Data. Updated September 9, 2026.
4. Centers for Disease Control and Prevention. Blacklegged Tick Surveillance. Updated May 14, 2026.
5. Eisen RJ, Eisen L. Changes in the geographic distribution of the blacklegged tick, Ixodes scapularis, in the United States. Ticks Tick Borne Dis. 2023;14(6):102233.
6. Burrows H, Talbot B, McKay R, Slatculescu A, Logan J, Thickstun C, Kulkarni MA. Rapid Northward Expansion of the Blacklegged Tick, Ixodes scapularis, in Response to Climate Change. J Med Entomol. 2025.
7. Eisen RJ, Eisen L. Evaluation of the association between climate warming and the spread and proliferation of Ixodes scapularis in northern states in the Eastern United States. Ticks Tick Borne Dis. 2023;14(6):102261.
8. Centers for Disease Control and Prevention. What to Do After a Tick Bite. Updated June 9, 2026.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention