CDC: Lyme Disease Cases Increase Dramatically Due to Change in Reporting

The CDC revealed that Lyme disease cases in the United States increased about 70 percent in 2022 due to new reporting measures.

The Centers for Disease Control and Prevention (CDC) headquarters in Atlanta on April 23, 2020. Tami Chappell/AFP via Getty Images

Lyme disease cases in the United States increased about 70 percent in 2022, according to data from the U.S. Centers for Disease Control and Prevention (CDC), which said that it was due to a change in reporting.

Reported cases of the tick-borne bacterial infection surpassed 62,000 in 2022 after it averaged about 37,000 each year from 2017 to 2019, the agency said Thursday in a report.

Traditionally, health departments received positive lab tests and went back to doctor’s offices to gather more information about the patients. But reporting fell off in 2020 and 2021 when health department staffers were busy working on COVID-19.

Starting in 2022, all that’s required to report cases—at least in high-incidence states—is a positive lab test. It’s possible that better, more sensitive testing is being used more and that may have contributed to the increase, CDC officials said.

“Before 2022, many of these cases would have been excluded, either because health departments were unable to obtain the necessary clinical information or because available clinical data were inconsistent with the objective criteria specified in the case definition,” the report said.

An estimated 476,000 Americans are diagnosed with it each year, but only a fraction are officially reported. With the reporting changes, it’s possible that the new Lyme testing requirements may give a better overall picture of how many people actually suffer from the illness, although CDC officials said it’s too early to tell.

In the report, the CDC said, “Although the total number of reported cases is higher than in previous years, it still does not approach the estimated 476,000 Lyme disease diagnoses estimated to occur annually in the United States, a frequency that highlights the need for effective prevention methods.”

Lyme disease, caused by the bacteria Borrelia burgdorferi, was first reported in Lyme, Connecticut, and is the most common infection from ticks in the United States. Cases generally occur in the Northeast, mid-Atlantic, and Midwest states.

The report said that the increase in Lyme cases in 2022 was larger among older Americans, saying that it doubled among adults aged 65 and older relative to the previous years. It might be due to more frequent testing among those age groups, “proportionally more disseminated illness in older age groups,” or “ proportionally more positive laboratory test results related to previous exposure B. burgdorferi rather than a current illness,” according to the CDC.

“So we’re capturing a bigger piece of that pie. And we’re saving them time,” Kiersten Kugeler, an epidemiologist in the CDC, told Stat News about the report.

It has long been noted that Lyme disease is notoriously difficult to test because testing doesn’t detect the bacterial infection in the first several weeks after the tick bite. Instead, the tests look for antibodies, which only develop over time, meaning that some patients may develop long-term symptoms of the bacteria long after they’ve been bitten.

“For the early stages of disease, it’s primarily a clinical diagnosis. It’s someone coming into their doctor … saying, ‘Hey, I don’t feel well. Look at this rash on my leg. I was outside a couple of weeks ago.’ And they go: ‘Oh yeah, you’ve got Lyme disease,’” Ms. Kugeler said, likely referring to the telltale bullseye rash that sometimes develops at the spot where the tick bite was located. Many cases of Lyme, however, don’t include a rash, health officials say.

She added that the CDC’s change means that it will provide clearer data on how many Lyme cases are actually being reported, while other officials conceded to Stat that Lyme reporting has been imperfect over the years.

Symptoms

Symptoms of Lyme disease initially include fever, chills, general malaise, joint pain, muscle pain, stiff neck, and the bullseye rash. The disease is spread via black-legged or deer ticks, which are common throughout the U.S. East Coast.

Without treatment in a timely manner, some health officials say the bacteria will continue to spread throughout the body over weeks, months, and years.

Late-stage Lyme can occur months or years after the tick bite, officials say. Common symptoms include swelling of one of the knees or other large joints well as arthritic-type pain, fatigue, joint or muscle pain, and nerve pain. Other complications include weakness or paralysis in the facial muscles, meningitis, heart problems such as endocarditis, or numbness in a nerve.

A tick whose bite can transmit Rocky Mountain spotted fever, at the French National Institute of Agricultural Research in Maison-Alfort, France, on July 20, 2016. Bertrand Guay/AFP via Getty Images

Treatment?

Generally, health care providers prescribe a 10 to 14-day course of antibiotics such as doxycycline to treat early Lyme disease, although other antibiotics can be used such as amoxicillin, cefuroxime, and azithromycin. Later-stage Lyme infections can require longer courses of the medication.

However, over the years, some authors and makers of supplements have suggested that herbs such as the Amazonian rainforest vine cat’s claw, Japanese knotweed, Andrographis paniculata, grapefruit seed extract, otoba bark, garlic, Chinese skullcap, and berberine may be effective at treating long-term Lyme cases. Several studies have been commissioned to test the efficacy of these herbs

A study published by the U.S. National Institutes of Health in 2016 concluded that “antimicrobial agents derived from natural sources such as plants, herbs, spices, fruits, and essential oils,” including several of the aforementioned ones, “have shown activity against” the bacteria.

The Associated Press contributed to this report.