No, Lyme Disease Cases Didn’t Spike—Here’s What You Need To Know

Fact checked by Nick Blackmer

Key Takeaways

• A report by the CDC shows that Lyme disease cases in the U.S. jumped by almost 70% in 2022 compared to previous years.

• Experts say that the drastic increase is likely due to a change in how Lyme disease cases are reported, mainly in states where the incidence is high.

• Tick-borne illnesses are also rising due to changes in climate patterns, land use, and deer populations.

Lyme disease cases in the United States rose by almost 70% in 2022 compared to previous years, according to a new report by the Centers for Disease Control and Prevention (CDC).

The average number of cases reported to the CDC between 2017 and 2019 was a little over 37,000 each year. In 2022, the number surged to over 62,000—a 1.7-fold increase from the annual average.

However, experts say that the notable jump in Lyme disease cases is likely due to a shift in disease surveillance methods rather than a sudden increase in the actual number of cases.

“While the cases are going up gradually, the spike is probably an artifact from the change in case reporting,” John Aucott, MD, director of the Johns Hopkins Lyme Disease Clinical Research Center, told Verywell.

Here’s what you need to know about how cases are being reported now, if Lyme cases are actually rising, and what could be causing the increase.

Related: Is Lyme Disease Treatable?

Did Lyme Disease Cases Actually Spike?

Lyme disease cases nearly doubled in 2022 primarily because of a change in how cases are reported. In 2022, the CDC changed its surveillance criteria to make it easier for states to report Lyme cases because “some were having a hard time keeping up with the reporting requirements,” especially with COVID-19, according to Aucott.

Right now, the new reporting system is only being used by high-incidence states, including Delaware, Massachusetts, New York, and Wisconsin.

All that’s needed to report cases of Lyme disease in high-incidence states is a positive lab test. Previously, clinical data and several related forms were needed.

The old reporting system required providers to fill out a case reporting form, which included questions about whether a patient had a rash and other clinical information, said Aucott.

After providers filled out the form, they sent it to the county health department. From there, officials forwarded it to the state health department, where it was determined if the patient was positive for Lyme or not. Finally, officials would report that information to the CDC.

“The multi-step processes involve a lot of human beings, which made it unreliable. It’s also so time-consuming and so expensive that a lot of the states weren’t able to keep up with it,” said Aucott.

The updated reporting system relies on laboratory test results and doesn’t need a provider to record so much clinical information, Andrew Handel, MD, a pediatric infectious diseases expert at Stony Brook Children’s Hospital in New York, told Verywell.

Related: How to Tell If You Have Lyme

Aucott thinks low-incidence states that continue to rely on the old reporting system could experience an undercount in Lyme cases, since the confirmation process relies on case reporting forms from providers.

Related: Living With Lyme Disease

Is the New Reporting System Accurate Enough?

While the new reporting system may seem like an improvement compared to the old reporting system, there are some limitations to its accuracy and totality.

Like Aucott said, it could lead to underreporting of cases in states that aren’t using the new reporting system. A state like California could get lumped into a low-incidence state category even though parts of it are high-incidence, such as Northern California and north of San Francisco.

“It also implies that there’s not that much Lyme disease in the low-incidence states, which I think is an oversimplification,” he added.

The updated reporting system also does not account for tests that may give false-positive results. If someone who had Lyme disease several years ago suspects they have it again, a test could be positive even if they don’t actually have the illness.

That’s because Lyme antibodies remain in the blood for months or years after the infection clears, according to the CDC. “Therefore, the test cannot be used to determine cure,” the agency says on its website.

False negatives are possible, too. If someone with Lyme tests too early, their test result may be negative.

“Antibodies can take several weeks to develop, so patients may test negative if infected only recently,” the CDC says.

Related: Is There a Lyme Vaccine?

Are Lyme Disease Cases Actually Going Up? 

Regardless of how cases are being reported, Handel said that Lyme disease cases are increasing and have been in the last few decades. One of the main reason for the increase is climate change.

“As we have less cold winters and longer warm seasons, it gives more opportunity for ticks to reproduce, find hosts, and transmit these infections,” said Handel.

Other factors contributing to the rise in tick-borne illnesses include landscape changes and shifts in land use. When new construction goes up in an area that is heavily wooded, there’s a higher chance of coming across ticks and the animals that ticks thrive on, like rodents and deer.

“Deer populations are enlarging everywhere,” said Aucott. “More deer translates into more ticks because the ticks feed on the deer.”

How to Protect Yourself from Lyme Disease

To prevent Lyme disease, Aucott and Handel both recommend:

• Avoiding high-risk tick environments, like wooded areas and tall grass when hiking or camping.

• Wearing protective clothing like closed-toe shoes, long-sleeved shirts, and pants.

• Treating clothing and gear with permethrin (a broad-spectrum insecticide and insect repellent).

• Doing a thorough tick check when you get home to make sure you don’t have any ticks on your body or clothes.

Related: Is Lyme Disease Contagious?

Which Ticks Spread Lyme Disease and Where?

In the U.S., Handel said there are two ticks that primarily spread Lyme disease: the blacklegged tick (or deer tick) and the Western blacklegged tick.

Most Lyme cases are concentrated in the Northeast, but they have spread southward toward the Mid-Atlantic states and slightly westward, leading to an increase in cases in Western Pennsylvania over the past decade. The upper Midwest, including Minnesota, has also emerged as another hotspot for Lyme disease, according to Handel.

Even if you take steps to prevent ticks, if you live in a high incidence area, completely avoiding them may not be possible. If you find a tick on your body, remove it as soon as you can, contact your healthcare provider, and watch for potential symptoms of a tickborne illness, including a rash (often in a bull’s-eye pattern for Lyme), headache, fever, chills, and muscle pain.

What This Means For You

A change in reporting has led to a rise in Lyme disease cases in the U.S., but experts say cases have also been increasing due to changes in climate patterns, shifts in land use, and a rise in deer populations. Preventing tick bites is your best defense against any tick-borne illness, including Lyme disease.

Read Next: What Happens If You Don't Treat Lyme?

Read the original article on Verywell Health.