Understanding tick-borne infections

CanLyme supports an understanding of Lyme disease that considers emerging research regarding co-infections, chronic forms of the disease, persistence of infection and alternate methods of transmission for tick-borne infections. 

Divergent perspectives

Much of the controversy around Lyme disease stems from divergent perspectives regarding tick-borne diseases. Some medical professionals and associations support a simplified view of the disease. From this perspective, the possibility of a Lyme infection is often discounted, symptoms are attributed to other ailments, and Lyme disease is ruled out for patients who have a negative Canadian two-tiered blood test or a positive test from an international laboratory, regardless of their testing standards. 

From this perspective, one or two short courses of antibiotics are considered to be effective in eradicating the bacteria, further treatment is considered unsafe and ineffective, and co-infections for the most part are not considered. Unfortunately, these conclusions are based on limited and outdated information.

Emerging research contradicts this perspective of tick-borne illnesses on every front. Much is being discovered about the complexity of the pathogens and the diseases they cause, including the mental health manifestations of these pathogens. Patients and their healthcare providers are left to navigate this complex disease in the context of a healthcare system that has not yet embraced both the emerging evidence and the reality of the uncertainties that remain.

Caught in the crossfire

Differing perspectives regarding tick-borne infections are also evident in the treatment options that healthcare providers consider for these patients. Some follow guidelines written by the Infectious Diseases Society of America, or IDSA. These guidelines are very narrow and outdated and leave many patients with ongoing symptoms and potentially, ongoing infection. There are other guidelines such as those developed by the International Lyme and Associated Diseases Society, or ILADS, that support a more complex perspective of tick-borne infections. 

Some physicians have come under scrutiny for treating Lyme disease beyond those outlined in the IDSA guidelines. Fortunately, there are a growing number of healthcare providers in Canada that are helping their patients despite these challenges, and gaining valuable expertise in the process. Much of this care comes at a financial cost to patients, and those who can’t afford it are left trying to navigate their own solutions without a healthcare provider to oversee their care. All of these challenges make collaboration amongst clinicians critically important.

Reported cases don’t tell the whole story

In 2021 there were 3147 reported cases of Lyme disease in Canada. A combination of very specific symptoms and confirmatory laboratory results are required for a patient to be counted as a probable or confirmed case of Lyme disease in Canada. Health Canada advises that these criteria are meant for surveillance and epidemiologic purposes only.1

In contrast, in the United States, the CDC estimates that 476,000 Americans are diagnosed and treated for Lyme disease each year. Considering the close proximity of Canadian provinces to endemic areas of the US, the expanding territory of ticks, and limitations in testing and case reporting parameters, the number of cases and scope of this problem in Canada is likely much higher than reports indicate.

Different strains of Borrelia and several other tick-borne pathogens can be found across Canada and worldwide, and risk maps reflect surveillance data which is inherently limited. In Canada and worldwide there are many areas with limited or no active surveillance, and birds and animals are constantly carrying ticks into new territory. For that reason, data from bordering provinces and states should also be considered along with a patient’s extended travel history.

Acknowledging the complexity of tick-borne pathogens

Lyme disease is one of multiple interacting vector-borne infections that can be transmitted by routes beyond a tick bite. It is most commonly caused by a corkscrew shaped bacteria, Borrelia burgdorferi, which has unique properties that enable it to move out of the bloodstream into tissues, take on various morphologies, become dormant, evade the immune system and trigger various immune and inflammatory processes. Manifestations of vector-borne diseases can be found in virtually every system in the body, including the brain and nervous system, heart, skin, joints, stomach and eyes. 

Tick-borne diseases can be difficult to diagnose and treat

Borrelia are complex organisms, and disease manifestations can also be complex and vary widely between patients. Patients may have Lyme disease along with other tick-borne infections often referred to as co-infections, other infections including reactivated viruses, and other medical problems which may or may not be related to Lyme. Patients with Lyme disease may be diagnosed with other diseases such as Fibromyalgia, ME/CFS, MS, juvenile arthritis and other autoimmune and inflammatory diseases before receiving a diagnosis of Lyme disease. Including Lyme disease in the differential diagnosis early on is essential. Lyme disease is much more challenging to manage when diagnosis and treatment are delayed. 

More research is needed

Historically, the research of Lyme and other tick-borne infections has been limited when contrasted to the complexity and severity of the disease. Research in the area of testing and treatment for chronic Lyme disease has not been sufficient to adequately address this rapidly growing problem. Fortunately, there has been a steady increase in solutions focussed research in the past several years, often organized and funded by advocacy organizations, foundations and individuals who have been impacted by these diseases. Much more research is needed; without it, clinicians will lack the tools they need, and patients will continue to suffer.


  1. National case definition: Lyme disease