Lyme disease is emerging in Canada, and is expected to increase with climate change, but effective, enhanced surveillance and clinician awareness will be key to minimizing the impact of the disease, write researchers in a review in CMAJ (Canadian Medical Association Journal) http://www.cmaj.ca/press/pg1221.pdf (www.cmaj.ca).

Lyme disease is transmitted by ticks which feed on animal or human hosts. It begins with a skin lesion that expands and if untreated, can result in facial palsy, meningitis, cardiac issues and progress to nerve damage (peripheral neuropathy) and inflammation of the brain and spinal cord (encephalomyelitis).

Epidemiological understanding about a patient's likely exposure to ticks is key, as serological testing is insensitive in the early stages of disease but can be useful in the later stages.

Current passive surveillance for ticks has identified new endemic areas in Canada but additional methods are needed to identify emerging areas of Lyme disease. Populations of the tick (Ixodes scapularis) are emerging in southern Ontario, Nova Scotia, southeastern Manitoba, New Brunswick and southern Quebec. Tick populations (I. pacificus) are widespread in southern British Columbia, although the prevalence of the Lyme disease agent (Borrelia burgdorferi) in those populations is lower than in the tick spreading in the east.

Vigilance by clinicians will help in disease surveillance and in prompt treatment. An important role of surveillance will be to inform the public and physicians about local risks and what to do for prevention and early diagnosis of Lyme disease.

"Lyme disease is emerging in Canada, and effective, enhanced surveillance needs to be instigated, and physician awareness of Lyme disease will be crucial to minimizing the impact of the disease," write Dr. Nicholas Ogden from the Public Health Agency of Canada and coauthors.