About Lyme Disease

Lyme disease (or Lyme borreliosis) is a multisystem infection caused by the bacteria Borrelia and is transmitted through the bite of infected blacklegged ticks (Ixodes species). It is one of the most reported vector-borne diseases in North America. It is an emerging illness in Canada due to various factors such as ticks migrating northward as the climate warms and the tick’s hosts (e.g., mice) also migrating.

The early manifestations of Lyme disease include flu-like symptoms, and a characteristic skin rash called erythema migrans. If left untreated, Lyme disease can lead to debilitating symptoms, affecting the nervous, musculoskeletal and cardiovascular systems. Lyme disease presents itself in three stages:

• early localized disease,
• early disseminated disease, and
• late disseminated disease.

The diagnosis of Lyme disease currently relies on the patient's history of exposure to infected ticks (if known), on clinical presentation and on outcomes of diagnostic tests—with a level of uncertainty for each factor.

Clinical manifestations vary considerably between affected people, making diagnosis of Lyme disease based on symptoms challenging. The accuracy of tests for Lyme disease varies depending on the stage of the disease, with late-stage Lyme disease being easier to detect than the early stages due to the immunological response happening during disease development.

Date modified:

2023-05-03