About Lyme Disease

Lyme disease (or Lyme borreliosis), a multisystem infection caused by the bacteria Borrelia and transmitted through the bite of infected blacklegged ticks (Ixodes species), is one of the most reported vector-borne diseases in North America. It is an emerging illness in Canada due to various factors, including the migration of ticks northward as the climate warms and as host vectors migrate.

Lyme disease early manifestations include flu-like symptoms as well as characteristic skin rash called erythema migrans. If left untreated, it can lead to debilitating symptoms, affecting the nervous, musculoskeletal and cardiovascular systems. The clinical manifestation of Lyme disease presents itself in three stages: the early localized disease, the early disseminated disease, and the late disseminated disease. The diagnosis of Lyme disease currently relies on the patient 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.

The clinical manifestations vary considerably between affected people, therefore the clinical diagnosis of Lyme disease based on symptoms can be challenging. The accuracy of diagnostic tests and test regimen for Lyme disease is variable 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 the course of the disease development.

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