What is Tick borne disease?
Tick borne disease (TBD) refers to various infectious pathogens (bacteria, viruses, fungi, protozoa, parasites) that can be transmitted via the bite of a tick. For simplicity, many use “Lyme and tick borne disease” to refer to this vast array of pathogens. When bitten by a tick, it is common to be exposed to more than one infectious agent, which results in various clinical presentations which we refer to as “tick borne disease”. Variables such as co-infections, genetics, virulence plasmids, and re-activation of previous infections may play a role in how a patient presents for medical attention. This may result in improper diagnosis and treatment with a prolonged course of infection for many patients with TBD. Lyme disease is known to cause a type of immune suppression (particularly when Babesia co-infection is present), that can result in re-activation of past viral infections or common bacteria usually thought of as non-pathogenic in the immune- competent host.
Below are a few infections known to be associated with tick bites:
- Lyme disease (Borreliosis, most commonly caused by B. burgdorferi in the United States; B. afzellii, B. garinii most commonly seen in Europe)
- Borrelia mayonii
- Borrelia miyamotoi
- Rickettsia species (R. rickettsii, R. parkeri, R. helvetica, e.g.)
- Babesia species (B. microti, B. duncani, e.g.)
- Mycoplasma pneumoniae
- Re-activation infections (EBV/mononucleosis, HHV-6, Chlamydia pneumoniae, Bartonella species, etc.; Note: Bartonella has been associated with tick borne disease, but the mode of transmission is currently under investigation)
- Relapsing fever Borrelia (caused by B. hermsii)
- Viral infections (Powassan virus; Bourbon Virus, Heartland Virus, Colorado Tick fever in other parts of the United States)
Because of the likelihood of co-infections or re-activation, the clinical presentation of Lyme and TBD is variable. Below is a list of some symptoms associated with Lyme disease:
- bull’s eye rash (a.k.a. Erythema Migrans or EM, may be solid, can be raised or slightly itchy, ranges from pale pink to deep red, may be single or multiple; diagnostic for Lyme disease); other types of rashes can be seen as well. Many patients with the persistent or chronic form of the infection have recurrent EM type rashes that come and go.
- fevers, chills, malaise
- facial palsy (or numbness/ neuropathic sensations on the face/head)
- shortness of breath (“air hunger” or “unable to take a full breath”)
- stiff neck or neck pain
- disturbed sleep (often treatment resistant)
- depressed mood, anxiety
- migratory joint pain +/- swollen joint/s
- shooting pain, numbness, tingling
- tinnitus (ringing/ buzzing in the ears)
- dizziness/ poor balance
- gastrointestinal symptoms (can mimic IBS)
- brain fog (difficulty thinking, mild memory/cognitive difficulty)
- other: jaw pain, rib soreness, abdominal pain, hoarseness, persistent phlegm in throat
The diagnosis of Lyme disease is based on both clinical and laboratory information. In some people who have recently been exposed to a tick infected with Borrelia burgdorferi, a Bull’s Eye rash (or Erythema Migrans rash) is sufficient for a diagnosis (and a blood test will be negative at this point, unless the individual had been exposed to Borrelia in the past). The infection spreads to distant locations (joints, nervous system, liver, heart, muscle, etc.) within a few weeks of infection (if not sooner) and can cause musculoskeletal complaints (migratory joint pain is typical), nervous system complaints (shooting pains, palpitations, autonomic dysfunction with dizziness and low blood pressure, facial palsy, creepy-crawly sensations, headaches, cognitive/ memory difficulties) and disturbed sleep. After being infected for 4 weeks or so, a Lyme Western Blot is sometimes positive. The CDC (and IDSA) recommends testing with a “Two Tier” system—checking ELISA and then Western Blot. The sensitivity for this testing combination can be quite low for patients who have been infected for more than a few weeks, so many physicians opt to order the Lyme Western Blot without the ELISA. Some labs test for different bands, which complicates interpretation of the test, and the CDC has guidelines that define a “positive test” if several bands are present. After Lyme disease is present for a longer period of time (e.g. years or decades), a person’s immune system may not be able to mount a sufficient response for even the Western Blot to be positive, so some physicians will order more specialized tests (such as the iSpot/ Elispot, CD57 NK cells, C6 peptide), but these test results are not consistently accurate in patients with chronic Lyme infection. At the time of writing this summary, there is no true gold standard test for Borrelia burgdorferi (Lyme disease). PCR has shown to have low yield in patients infected for a longer period of time (months to years) and culture has been very difficult due to the fastidious nature of the organism (it grows very slowly and has very specific culture requirements).
The above mentioned bacterial infections usually respond to antibiotics. Because of the various forms of Borrelia (spirochete, cyst, biofilm), it is necessary to treat with combination antibiotics. Many patients with early infection (e.g. Bull’s Eye rash, fever, headache, neck stiffness) progress to the chronic or late phase despite treatment as recommended by the CDC (14-21 days of doxycycline or amoxicillin are most commonly prescribed by most physicians). For patients who have had longstanding infections, a longer treatment regimen is often necessary.
- Can Lyme disease be transmitted sexually? The lyme bacterium has been identified in various bodily fluids and may be transmitted sexually, though the actual risk of this is not well established at this time. It is recommended that those undergoing treatment use barrier protection (condoms) to prevent re-infection from their partner until their immune system has fully recovered.
- Can Lyme disease be transmitted from mother to fetus? It is thought that the Lyme bacterium can be transmitted during pregnancy and the CDC recommends treatment with antibiotics for pregnant women diagnosed with Lyme disease.
- Is late stage Lyme treatable? There is controversy in the medical community regarding chronic symptoms associated with Lyme/TBD. Some physicians believe that ongoing symptoms after short term antibiotics are due to “Post Treatment Lyme Disease Syndrome”, whereas other physicians believe that ongoing symptoms are due to an active infection that is treatable with a longer course of antibiotics. If a patient has structural damage to their joints from ongoing inflammation, some of their joint pain may not fully resolve with antibiotics.
- How long does a tick need to be attached for disease transmission? The amount of time required for disease transmission depends on the infectious agent and whether or not the tick has been primed (for some pathogens such as Borrelia, the bacterium needs to migrate from the tick’s midgut to the salivary glands prior to being transmitted). Some examples: Borrelia burgdorferi (Lyme disease), it is thought that disease transmission can occur within 4-72 hrs, Babesia microti 36-54 hrs, Anaplasma phagocytophilum 24-50 hrs, Powassan virus 15-30 min, Rickettsia rickettsii 2-96 hrs.
- What about post exposure prophylaxis with antibiotics? This is no longer recommended. In the past, the CDC advised treatment with a single 200mg dose of doxycycline after an Ixodes scapulars tick bite in an endemic area. This practice has not been shown to reduce the infection rate with Borrelia and can actually result in a false negative Lyme Western Blot test result, delay diagnosis and does not effectively treat most co-infections.
- What should I do if I am bitten by a tick? If you find an attached tick, remove it promptly with either a tick spoon or tweezers (do not squeeze the tick’s body, which may increase likelihood of disease transmission). You may send the tick for testing to the UMass Laboratory of Medical Zoology (www.tickreport.com), and share the results with your physician. Take a photograph of the tick and any rashes—share this information with your physician. If you develop a fever, neck stiffness, fatigue or other concerning symptoms, contact your physician promptly. IMPORTANT: If you develop flu-like symptoms in the summer in an endemic area, be suspicious of a TBD even if you do not recall a tick bite. It is not recommended to take post exposure prophylaxis (i.e. one or two doses of doxycycline after a tick bite) for the reasons noted above.