What is Lyme disease?
Mainly transmitted through the bite of an infected tick (spiders, horseflies … can also transmit the disease) it is an infectious disease (reportable in Canada) caused by a bacterium, Borrelia burgdorferi. Lyme disease or Lyme borreliosis is what we call a zoonosis that is an infectious disease of animals that can be transmitted from animals to humans as the plague or rabies. Discovered in 1975 for the first time in Lyme city (Connecticut) in the USA, the disease is transmitted in Canada mainly through two species of well-defined ticks:
- Western black-legged tick (Ixodes pacificus) in British Columbia
- The black-legged tick (Ixodes scapularis, or deer (or roe deer ) tick) in the rest of Canada
Once the subject has been bitten, the disease will evolve in stages, from the skin to the blood and tissues:
- Stage 1: the infection remains latent in the early hours (12-24 hours) after the bite
- Stage 2: the infection begins to spread in the days and weeks following the bite
- Stage 3: the infection becomes chronic as no diagnosis was made and no treatment was administered and all this several months or even several years after the bite
You should know that Lyme disease is very treatable when it is diagnosed early, i.e. in its first stage, hence the importance of prevention and diagnosis; we will give more details about this below.
Ticks, the vector of borreliosis
Ticks, warning, danger!
The diagnosis of the disease is very complicated for the simple reason that the vector of the disease, namely the tick, is a very small parasite (ectoparasite mite) whose bite is painless and inconspicuous. Living in wooded and wet areas (forest, wood, grass …) ticks attack both humans and animals. Feeding on infected animals such as rodents, birds, deer … it is in this context that they themselves become carriers of the infectious agent that they transmit to humans, the bite transmitting any bacteria the tick could store in its previous meals.
Please note that the tick can transmit Lyme disease but also tularemia or Rocky Mountains spotted fever, the same patient may be affected by both Lyme disease and the co-infections (including infection with Bartonella)
The ticks family known in Canada as the number one vector of transmission of the disease remains the Ixodes tick, tick with particular characteristics:
- Black color
- 8 feet
- A size ranging from 5 mm to over 20 mm in adulthood particularly when the tick is fed
Therefore prevention is required
Lyme disease is increasingly present in Canada (the number of cases has multiplied by 10 in less than 10 years) (global warming is certainly one of its causes). We must therefore follow a few common-sense tips especially from spring to fall where the risks of being bitten are the highest, since ticks are the most active.
Be aware of the fact that, firstly, if ticks live at ground level, they are perfectly capable of jumping to tackle their new hosts and secondly that they travel without any problems via pets (dogs, cats …)
So during a walk in the woods (searching for mushrooms, hunting …), camping or if you are a professional (forest ranger, logger…) working in areas at risk, simple things must be done thoroughly each time after having finished your activity for optimal prevention:
- Wear clothing that covers your body and especially your legs (no shorts and open shoes)
- Avoid dark clothing (it is more difficult to identify ticks)
- Use a repellent with DEET (N, N-diethyl-3-methylbenzamide) and apply it on your clothes
- Check every part of your body. Be vigilant with children.
- Take a shower to get rid of ticks that are not yet attached
- Carefully inspect animals that can bring ticks into the house. Use products against ticks for your pet.
You should also maintain your green spaces to prevent the spread of ticks around your home (lawn mowed regularly to prevent long grass …)
What to do if I get bitten by a tick?
The sooner the tick is removed after the bite, the less the disease agent is likely to be transmitted to humans.
Using tweezers or a tick clamp that can be bought in pharmacies, you grab the tick by its head and pull straight back, steadily and firmly; the tick’s body is then straight, so perpendicular to the skin. Disinfect the bite area after removing the tick but especially not when the tick is still attached to the skin. It can take several seconds to remove it because the tick‘s hypostome, i.e. the mechanism that allows it to anchor firmly to its prey (made of teeth) is usually very resistant.
Symptoms of Lyme disease
There are several symptoms of Lyme disease and they differ according to the patients, which makes it even more difficult to diagnose it; the disease also has much in common with a simple flu that will not alert the patient immediately, the tick bite being mostly unnoticed. The cause and effect link is therefore generally not established (noticed) by the patient.
The sooner the disease is diagnosed, the more effective the treatment is, with a good chance of recovery. Otherwise, the disease becomes chronic with spreading to other organs: joints and the nervous system, hence the importance of carefully assessing all the symptoms as quickly as possible.
Progressive disease, there are 3 stages:
Stage 1: within a few days, usually a week, a red circle-shaped rash forms around the bite. Then between one to two weeks after the bite, if no treatment is administered, what is called erythema migrans appears, i.e. the redness extends more, which indicates that the bacteria has passed into the blood. This is usually accompanied by flu-like symptoms such as chills, tiredness, swollen lymph nodes, headache, fever, weakness, body aches …
Once again, even in stage 1, the symptoms do not appear in all patients and in most of them the symptoms of stage 1 disappear by themselves, but it does not mean that the disease has disappeared; quite the contrary, in fact.
Stage 2: within a few weeks or even months after the tick‘s bite, the disease will spread to other organs. The disease worsens and it will affect the nervous system, the joints, the skin but also vital organs such as the heart.
Therefore, we can notice the following symptoms:
- the paralysis of limbs or facial paralysis
- an irregular heartbeat, myocarditis, pericarditis …
- a rash that continues to spread
- visual disorders, conjunctivitis …
- a more intense pain in the joints
- cognitive disorders (difficulty in thinking)
Stage 3: If nothing is done, the whole body is affected; symptoms can then lead to chronic diseases such as arthritis. Other symptoms may occur but also worsen:
- digestive and urinary disorders
- a rash that worsens
- increasingly disabling muscle pain, the patient then having the physical condition of a person aged of 70 or 80
- a more severe cardiac impairment (tachycardia, extrasystoles)
- worsening brain damage (visual disturbances, memory problems …)
- breathing problems
Diagnosis and treatment of Lyme disease
A diagnosis often complicated
The diagnosis is often complicated because the most obvious symptoms (including rash) are not systematic in all patients, so they do not always tip the balance towards Lyme disease. Unfortunately, doctors do not immediately think of borreliosis so there is often a misdiagnosis that transforms the recognition of the patient’s Lyme disease in a real uphill battle in order to have the appropriate treatment.
Clinical signs and methodical questioning of the patient (a tick bite, the patient having been in a high-risk area …) makes the doctor request a specific serological test.
Please note that it takes 4 to 6 weeks after the tick bite for the antibodies to develop in the blood; all the blood tests that are performed too early would then produce false negative results. Meanwhile, the doctor will prescribe an antibiotics treatment as soon as possible even if the blood results are not yet known, precisely in order to block the spread of the bacteria.
The followings are laboratory blood tests, these tests looking for antibodies fighting the infection, two tests to be jointly requested (the two go together):
- Firstly an ELISA test is performed
- Then a Western Blot serology that will confirm the first result, if it is positive
Other additional tests:
- The Lymphocyte Transformation Test (TTL)
- A polymerase chain reaction examination or PCR, a very efficient examination because then the DNA of Lyme disease is detected in the patient’s body.
- Lumbar puncture if there are any doubts after negative blood results.
Effective treatment if the diagnosis is made quickly
The effectiveness of the treatment depends on how early the treatment is started and therefore on the diagnosis. A patient in stage 1 will then be much more likely to cure completely after the disease.
The main treatments are:
- Antibiotics taken orally more suited to early-stage disease (stage 1). This treatment usually lasts 2 to 3 weeks. The major antibiotics are based on Doxycycline, Amoxicillin and Cefuroxime.
- An antibiotic treatment by intravenous injection (ceftriaxone) is recommended for patients who have been diagnosed from the stage 2 of the disease.
- An intramuscular antibiotic treatment is also possible.