Lyme Diseases is a severe and potentially dangerous condition due to bacterial infection following bites from ticks in the genus Ixodes.

The infection can be treated with a course of antibiotics, but in 10 - 20% of patients ^ref.severe symptoms can persist :

Lyme disease is caused by infection with the bacterium Borrelia burgdorferi. Although most cases of Lyme disease can be cured with a 2- to 4-week course of oral antibiotics, patients can sometimes have symptoms of pain, fatigue, or difficulty thinking that lasts for more than 6 months after they finish treatment. This condition is called Post-Treatment Lyme Disease Syndrome (PTLDS).

Source : US Centers for Disease Control and Prevention,

The reasons for the lingering symptoms is unknown, with some patients still experiencing a variety of problems several years later.

There are no proven treatments for PTLDS - some trials of long-term antibiotic treatment have led to complications, and are not currently recommended.