(NEWS10) – The number of untreatable cases of Lyme disease could affect thousands of Americans.

Researchers say while most patients recover from Lyme disease, treatment fails in at least 10 to 20 percent of patients, who develop persistent symptoms including chronic pain, cognitive dysfunction, and fatigue. This is known as post-treatment Lyme disease (PTLD).

Using six datasets, researchers were able to estimate that by 2020 there will be between nearly 82,000 to nearly 2 million cases of PTLD in the United States.

Researchers say there is a large variance is estimated cases due to “vast under-reporting by health authorities.”

Each year, there is an estimated 400,000 cases of Lyme disease.

The CDC recommends the following to prevent Lyme disease:

  • Wear repllent
  • Check for ticks daily
  • Shower soon after being outdoors
  • Call your doctor if you get a fever or rash

Early symptoms of the disease include skin rash, fever, and joint pain. Timely diagnosis and antibiotic treatment can help most patients recover.