This monograph on Lyme disease, known
more accurately as Lyme borreliosis, was prepared by a group of Belgian
experts and was subsequently reviewed for accuracy by several specialized
What is Lyme borreliosis and how is it contracted?
Borrelia burgdorferi, the etiologic agent of Lyme
disease, is transmitted to humans
via the bite of infected ticks. Ticks can
bite humans throughout much of their lifecycle (larval, nymph, or adult stage)
but seem to most frequently transmit Borrelia during the nymph stage.
Nymphs are smaller (less than 2 mm in diameter) than adult ticks and thus more
often go undetected; they are more active in summer and early autumn.
What are some of the risk factors for contracting Lyme disease?
Taking part in out-of-door activities increases the risk of being
infected by B.
burgdorferi. The risk of transmission is also affected by various other
factors, including the length of time a tick remains attached to the body of the
host (transmission is most likely when a tick is attached for 24-48 hours); the
density of ticks in the area; the percentage of ticks carrying B.
burgdorferi (in Europe, an average of 14%; however, there is
significant regional variation); weather conditions; the types of vegetation in
the area; and the nature of the host’s outdoor activities.
What general precautions should be observed in order to avoid contracting Lyme borreliosis?
Experts generally recommend the following precautions for individuals
participating in out-of-door activities, particularly during the summer and
- Wear clothing that fully covers the body;
- Use insect repellent
- Inspect the body for ticks
- Remove any ticks from the skin as soon as possible;
- Treat outdoor gear with permethrin as needed
What are characteristic tick bite symptoms?
Within two days of being bitten by a tick, victims typically develop an itchy,
poorly-defined skin rash less than 5 cm in diameter. This reaction is
not a sign of borreliosis, but rather a standard
inflammatory or hypersensitivity
reaction to the tick bite. The lesion should fade naturally after two or three
days; as a general rule, patients are advised to monitor the area for changes.
A rash that persists longer than 4-5 days may be a sign of borreliosis;
patients should recognize, though, that such
lesions may likewise be due to a
variety of other (non-borreliosis)
bacterial infections resulting from the
bite or from removal of the tick.
It is important to note that a substantial proportion of individuals exposed
to B. burgdorferi will never develop clinical manifestations of
borreliosis. However, even in the absence of symptoms, exposure to B.
burgdorferi prompts the production of
antibodies specific to the
bacteria: this explains why such
antibodies have been detected in a substantial number of asymptomatic
What are the clinical manifestations of Lyme borreliosis?
Lyme borreliosis is associated with a variety of symptoms, grouped below into
- Skin rashes (erythema
migrans) start at the site of the tick bite and gradually
expand outward, sometimes reaching diameters of 30 cm. Such
lesions often occur in
the armpits, knees, groin, perineum, back, and buttocks, as well as
on the head, and in some cases are associated with local pain. Other
accompanying symptoms may include muscle and joint pain, low-grade
fever, fatigue, and adenopathy. The lesions frequently last no
longer than a month and fade on their own, without medical
- “Secondary” cutaneous lesions (multiple erythema
migrans) are typically smaller than the primary lesion
and frequently appear days or weeks – if not months or years – after
the initial tick bite. They fade naturally over time and are
associated with various nonspecific symptoms, among them muscle or
joint pain, low-grade fever, fatigue, and adenopathy. These
secondary lesions result from dissemination of the
bacteria throughout the
body: B. burgdorferi may spread via the bloodstream to the
nervous system, joints,
and heart. Other organs (e.g., the eyes and
liver) may also be
affected, though this is highly atypical.
- In rare instances, patients may develop
benign lesion that
generally manifests 1-6 months after a bite. Lymphocytomas present
as small, purplish-red nodules and are most frequently found on the
earlobe. In the event of an equivocal diagnosis, a biopsy may be
- Neurological damage may manifest as headaches or as
paralysis; in such cases, paralysis is often accompanied by
neuropathic pain that is more pronounced at night. Damage to the
cranial nerves may result in paralysis of the facial muscles,
abdominal wall, or lower extremities (paresis). In children,
paralysis often takes the form of acute facial nerve palsy.
- Cardiac manifestations are rare and typically involve
spontaneously-resolving conduction disturbances (reduced heart
rate). More serious cardiac disorders may also occur, but are rare.
- Lyme arthritis most commonly affects the knees; this
reaction emerges months, if not years, after the initial tick bite.
Additional symptoms (less common):
- Acrodermatitis chronica atrophicans chiefly affects
women and is characterized by cutaneous lesions that may not appear
until 10 years after the initial tick bite. The condition may be
accompanied by other symptoms, among them arthritis, dislocation of
hand and foot joints, and Achilles tendinitis
- If early-stage Lyme
disease is left untreated,
patients may develop late Lyme neuroborreliosis, which
involves gradual damage (developing over more than six months) to
the brain or spinal cord. Signs of neuroborreliosis include numbness
in the legs, ataxia, paralysis of the extremities, and
Lyme borreliosis and pregnancy: Lyme borreliosis is
not transmitted from mother to fetus; indeed, the
disease is not transmissible
between humans. Though previous publications have raised concerns about Lyme
borreliosis and pregnancy outcomes, these
fears appear to be unfounded: there is no clear link between the disease and
premature delivery, fetal death, or
In some instances, individuals with a documented history of Lyme
disease who received appropriate
treatment at the onset of their
illness have nonetheless reported the persistence (longer than 6 months) of
nonspecific symptoms. These include fatigue; recurrent, migratory
musculoskeletal pain; impaired memory and/or concentration; and migraines. This
condition is sometimes described as post-Lyme disease treatment
syndrome, a diagnosis not without controversy: indeed, the scientific
community continues to debate whether the syndrome actually exists. Opponents
argue, for instance, that some patients with a history of Lyme borreliosis may
actually have been misdiagnosed (i.e., not all patients who report such symptoms
may have had the disease in the first place); they also point out that there is
no evidence that borreliosis patients are more likely to experience these
symptoms relative to the general population.
What are the most effective therapies for the various forms of Lyme borreliosis?
Regardless of specific symptoms, all Lyme borreliosis patients should receive
therapy. Principal components of these
antibiotic regimens include doxycycline or a combination of ceftriaxone and
penicillin derivatives. The emergence of antibiotic-resistant Borrelia
species has not yet been reported. Among
patients who display no clinical symptoms of borreliosis, the presence of
specific anti-B. burgdorferi
antibodies in the bloodstream may be due
either to a prior Borrelia infection or to cross-reaction between
antibodies (i.e., a false positive result). In such cases, no
treatment should be administered, thus
avoiding unnecessary exposure to
If, in spite of appropriate antibiotic
therapy, the patient does not experience
significant improvement in health or does
not recover fully (the most common concern), the diagnosis must be reevaluated.
A prolonged course of treatment or extended
antibiotic regimen is not indicated, as the efficacy of such measures has not
been demonstrated; rather, they seem likely to unnecessarily expose the patient
to additional antibiotics.
Pregnant women ought also to be treated with appropriate
Lyme-related arthritis that lasts more than two months after a full course of
treatment is known as
arthritis and is rarely observed in Europe. In such cases,
antibiotics ought to be avoided, while
non-steroidal anti-inflammatory drugs and
corticosteroids are generally beneficial.
Should tick bite victims routinely receive antibiotics?
At present, Belgian specialists discourage
antibiotic prophylaxis in response to
tick bites. However, individuals who know or suspect that they have been bitten
should arrange to have the bite monitored by a clinician over the following
month. Health professionals should examine
the area around the bite for emergence of
erythema migrans, the most common symptom
How are different forms of Lyme borreliosis diagnosed?
Diagnosis of Lyme disease is either
clinical (based on presentation of specific symptoms) or serological (based on
blood tests). Serology is the method of choice and in most instances is the only
available diagnostic option. Prompt diagnosis of borreliosis also requires that
physicians be able to recognize and distinguish between the various
manifestations of the disease, as discussed above.
Diagnostic tests can be grouped into several overarching categories,
- I. Immunologic testing for IgG antibodies specific to
B. burgdorferi. If antibodies are detected, a second and more
specific test is required in order to confirm the results.
- II. Analysis of cerebrospinal fluid from a lumbar
puncture. If antibodies have been detected in the blood or if
neuroborreliosis is suspected, analysis should include tests for antibody
Other laboratory tests for Lyme borreliosis are available but have not yet
been approved for use. Of these, one of the most promising is a
PCR-based assay for detection of
bacterial DNA, though this
technique only exhibits sufficient sensitivity in patients suffering cutaneous
or joint-based symptoms.
It should be noted that serological tests for B. burgdorferi are not
effective in the absence of specific clinical symptoms, such as pain or
Detection of B. burgdorferi-specific antibodies in the absence of clinical symptoms/a discernible tick bite: how to proceed?
Detection of specific antibodies (IgG,
IgM) associated with Lyme borreliosis is not indicative of active
disease unless the patient also
presents with some of the symptoms described above. This can be explained as
follows: antibodies specific to Lyme borreliosis persist in the blood for a
significant period of time, even among patients who have received appropriate
antibiotics. Thus, a positive
immunologic test in an asymptomatic patient is never considered sufficient
grounds for antibiotic
Is it possible to be re-infected by B. burgdorferi?
Patients should recognize that B. burgdorferi IgG
antibodies have poor neutralizing
capabilities; the presence of these antibodies is thus not sufficient to prevent
reinfection. Such reinfections generally manifest as
Lyme borreliosis in Belgium: what data are available?
Cases of Lyme borreliosis have been observed throughout Belgium, though the
incidence varies from region to
region and from one year to the next. For instance, the
disease is rarely reported along the
Belgian coast but is more prevalent in other regions. Infection rates are
slightly higher among males, perhaps because men are more likely to take part in
out-of-door professional or leisure activities.
The number of borreliosis cases in Belgium has remained stable over the past
10 years, as determined by three separate investigations. On average, 1000 Lyme
disease patients were hospitalized
each year from 1999 to 2010 (the last year for which data are available). An
increase in hospitalizations was noted at the beginning of the decade; this
uptick likely reflects the increasing sophistication and wider availability of
diagnostic tests for Lyme borreliosis