Lyme Disease
the spread of ticks in Canada and what you should know
When you hear the term Lyme disease, the first thing that likely comes to mind is the image of a blacklegged, blood-sucking tick. Ticks themselves do not cause Lyme disease, but rather can carry certain species of bacteria that do. The primary Lyme disease causing bacteria in North America is Borrelia burgdorferi, while in Europe Borrelia garinii is the most common. Not all ticks carry the Lyme disease causing bacteria, but upward of 20% of the blacklegged tick populations in some at-risk Canadian cities have tested positive for Borrelia in recent years. Lyme disease occurs when Borrelia burgdorferi move into the blood through the site of the tick bite and attach to the inside of the blood vessels to cause an early localized infection. Without treatment, the bacteria can move to and infect other parts of the body causing further long-term complications.
Risk Areas
The risk of a tick bite is greatest during warmer months, from early spring to late fall. In milder regions of the country with little snowfall there is also a risk of tick bites throughout the winter. Ticks like to live in tall grassy or wooded areas, as well as on animals, including mammals and birds.
Between 2011 and 2017, there was a 700% increase in Lyme disease diagnoses recorded in Canada, from 266 to 2,025 cases. This increased prevalence is due to the spread of blacklegged ticks in central and eastern Canadian cities and rural areas, likely caused by warming temperatures and the tick’s ability to hitch a ride on migratory birds and mammals.
Although this increased number of cases is troubling, there are many preventative measures that we can take to protect ourselves against tickborne Lyme disease.
Prevention
If you enjoy spending time outdoors, but want to avoid getting tick bites and possibly exposing yourself to Lyme disease, follow these tips:
- Cover up when in wooded or grassy areas and stick to designated trails to prevent ticks from attaching to the skin and finding a place to bite.
- Tuck shirts into pants and pants into socks, and wear light coloured clothing so you can easily visualize and remove dark coloured ticks.
- Treat clothing and gear with products containing permethrin and spray skin with bug repellent containing N,N-Diethyl-meta-toluamide (DEET) or icaridin to deter ticks.
- Upon returning indoors check your entire body thoroughly for ticks and shower immediately to prevent attachment.
- If you find a tick attached, remove it immediately with tweezers, as the probability of transfer of Borrelia through the tick bite is low within the first 24 hours.
- Place worn clothing in dryer on high heat for 10 minutes to kill any remaining ticks.
With the increased presence of blacklegged ticks in eastern and central Canada, it is also important to know the signs and early symptoms of Lyme disease to prevent its progression and associated complications.
Symptoms and Diagnosis
The time to onset of first symptoms can vary between individuals, presenting within days to several weeks of a tick bite. The earliest symptoms of Lyme disease can include a characteristic bullseye skin rash of migrating redness (erythema migrans), which is present in 50-80% of individuals, along with flu-like symptoms such as fever, headache, body aches, neck stiffness, and fatigue.
If left untreated, further symptoms can appear in the following weeks to months including erythema migrans on other parts of the body, arthritis manifesting as severe joint pain at one or several joints, and several neurological issues. Lyme disease can also result in neurological issues, such as numbness or weakness in the limbs, inflammation of the lining of the brain (meningitis), and temporary paralysis of one side of the face (Bell’s palsy). Individuals living with chronic Lyme disease may also experience heart problems, liver and eye inflammation, and severe fatigue.
Gastrointestinal manifestations, such as lack of appetite resulting in weight loss, nausea, vomiting, diarrhea, and abdominal pain are also common in the early stages of Lyme disease. Further, liver function can be negatively affected in individuals with Lyme disease, and is more likely to occur as the bacteria move out of the blood vessels into nearby tissue. Elevations in specific liver enzymes, such as aspartate- and alanine- aminotransferases, have been reported in Lyme disease patients. With appropriate treatment, liver function can improve within three weeks.
For an extensive list of symptoms that can be associated with Lyme disease please refer to www.canlyme.com/lyme-basics/symptoms/.
A positive Lyme disease diagnosis is typically made through recognition of erythema migrans, confirmation of potential exposure to Lyme disease risk area and/or history of tick bite, and testing for specific antibodies to Borrelia bacteria in the blood. Antibody testing may present a limitation as they may not always be present in the blood at early stages of the disease.
Treatment
Several antibiotics, including doxycycline, amoxicillin, and cefuroxime, have been reported as effective treatments for Lyme disease, depending on the stage and which parts of the body are affected. Early, localized Lyme disease, in the absence of neurological involvement, can be effectively treated with oral doxycycline or amoxicillin. Doxycycline is contraindicated during pregnancy or lactation and in children younger than eight years of age. Additional antibiotics, such as penicillin or ceftriaxone, delivered intravenously may be required for individuals with neurological symptoms or more advanced disease. Unfortunately, many individuals with chronic Lyme disease may experience recurrences of severe muscle and joint pain, and severe fatigue even after appropriate treatment.
Protecting Your Pets Against Tick Bites and Lyme Disease
It can be difficult to know where to start when checking your furry best friend for ticks after a walk through the forest. Keeping your pets on the designated trail, especially in off-leash parks, may be difficult and complicates a major preventative measure that we ourselves can rely on heavily to prevent tick bites. Interestingly, only 5% of dogs are reported to show symptoms after a Lyme disease-transmitting tick bite, including weight loss due to a lack of appetite, lethargy, swollen joints, and in some cases, lameness resulting in a limp. Antibiotic treatment can only be given to dogs that display these symptoms and where there is evidence of exposure to a Lyme disease transmitting tick risk area. Preventing tick bites in the first place is therefore key to protecting your pets. If you suspect your pet may have Lyme disease, contact a veterinarian.
Know Where to Check Your Pets
Check by running your fingers, while applying gentle pressure, through your pet’s fur to feel for bumps. Concentrate on warm, protected areas of your pet where ticks would not easily fall off such as in and around the ears and eyelids, under the collar, under the front and between the back legs, between toes, and around the tail. If you locate a tick, remove it carefully with tick tweezers, which make it easier to remove the entire tick and prevent a localized reaction, or take your pet to the veterinarian for tick removal.
Preventative Therapies
There are topical creams available that you can apply to the back and neck of your dog, which stop the tick from biting them in the first place. Topical application can be difficult for pets with longer fur and for water-loving animals as it is no longer effective after a swim in a pond or lake. Oral treatments are also available, which are effective for up to a month and work by causing the tick to fall off as soon as it tastes medicated blood. Discuss the best tick preventative products for your dog (as well as your cat, as they can be highly sensitive to many chemicals!) with a veterinarian.