LYME DISEASE
Lyme disease is caused by members of the Borrelia burgdorferi sensu lato complex.
- There are roughly two dozen species in the Borrelia burgdorferi sensu lato complex; not all are human pathogens. The geographic distribution of the species is not uniform. In the United States, almost all reported cases of Lyme disease appear to be the result of Borrelia burgdorferi sensu stricto (Bbss) infections. In Europe, 3 species - B. garinii, B. afzelii, and Bbss, are responsible for most cases of Lyme disease. The various species are further divided into strains and there are hundreds of strains worldwide. For the purposes of this document, any Borrelia burgdorferi sensu lato complex infection causing Lyme-like symptoms will be considered under the heading of Lyme disease.
- Differences between genospecies of Borrelia produce variable clinical presentations, variable antibody responses and possibly a variable therapeutic response.
- More recently identified black-legged tick transmitted pathogens Borrelia mayonii and the relapsing fever relative Borrelia miyamotoi have been documented to cause Lyme-like illnesses. Both seem to respond to the same treatments used for Lyme caused by B. burgdorferi.
- Other blacklegged tick-borne pathogens are discussed as co-infections. A single tick bite can transmit multiple pathogens; tick bites occurring in succession may result in transmission of different pathogens at different times. It is not unusual for Lyme disease patients to be multiply infected.
CO-INFECTIONS
Black-legged ticks have been shown to transmit several other pathogens in addition to Borrelia burgdorferi.
- It is important to consider co-infecting pathogens like Babesia, Anaplasma, Ehrlichia and Bartonella for people who have risk factors for those illnesses and/or persistent symptoms after antibiotic treatment for Lyme disease.
- The frequency of tick-borne co-infections in Lyme disease people from endemic areas ranges from 4 to 45%. When coinfections are left untreated, their continued presence increases morbidity and may prevent successful treatment of Lyme disease.
- Laboratory evaluation for co-infecting pathogens can be challenging. Performance parameters of available tests are variable and do not always account for the different strains that may be responsible for illness.
Some of the most commonly encountered co-infections are:
- Anaplasma: a white blood cell parasite that causes fever, headaches, generalized body aches and is associated with leukopenia (granulocytes), thrombocytopenia, and elevated transaminases.
- Babesia: a malaria-like piroplasm that invades red blood cells causing fever, fatigue, chills, sweats, headaches, dyspnea, and may be associated with anemia and elevated transaminases.
- Ehrlichia: a white blood cell parasite similar to Anaplasma and causing a similar clinical picture, the type of WBC invaded is species dependent; most commonly associated with Lonestar ticks, one type may be more associated with Ixodes ticks.
- Bartonella: intracellular parasite that invades erythrocytes, endothelial and other cells; increasing but still inconclusive evidence for tick transmission; associated with fever, lymphadenopathy, eye disorders, myocarditis, endocarditis, encephalopathy, musculoskeletal involvement.
- Powassan Virus: flavivirus with 2 lineages transmitted by different ixodes ticks. Lineage II also called deer tick virus; can cause severe neurologic symptoms; no known treatment; fatalities documented.
- Tickborne Encephalitis Virus: prominent in Europe and Asia, a flavivirus that affects the central nervous system; no known treatment; a vaccine is available in some parts of Europe; limited use owing to adverse effects in children.
SELECTED OTHER TICK-RELATED DISEASES
STARI, another important tick-borne disease
Southern tick- associated rash illness (STARI), a Lyme-like illness, has been associated with bites from the Lonestar tick (Amblyomma americanum), not blacklegged ticks. The bacterial pathogen has not been clearly established. Limited evidence supports antibiotic treatment similar to that for Lyme disease. The Lonestar tick’s range continues to expand and in addition to its southern and central distribution now includes much of the northeastern US.
Alpha gal allergy
This IgE mediated allergic reaction to galactose alpha 1,3, galactose (alpha gal) a carbohydrate found in red meat, is associated with Amblyomma americanum tick bites. Treatment is centered around management of delayed hypersensitivity reaction and subsequent red meat avoidance.
Tick paralysis
This is an ascending paralysis resulting from a neurotoxin released by tick salivary glands during feeding. Many species of ticks have been implicated. Treatment is removal of the tick.
Symptoms and Signs of Lyme Disease
The medical literature documents the protean manifestations of Lyme disease, and familiarity with its varied presentations is key to recognizing both acute and disseminated disease.
- Borrelia burgdorferi can infect any organ or tissue and thus, produce a wide range of symptoms.
- Lyme should be considered in the differential diagnosis of rheumatologic and neurologic conditions, as well as chronic fatigue syndrome, fibromyalgia, somatization disorder and any difficult-to-diagnose multi-system illness.
Common Symptoms and Signs of Early Lyme Disease
- Erythema Migrans rash
- Fatigue, malaise
- Flu-like symptoms, including fever, headache, arthralgias, myalgias
- Stiff neck
- Dysesthesia
- Lymphadenopathy
- Facial nerve dysfunction leading to weakness or paralysis of facial muscles (often mislabeled as Bell's palsy)
Common Symptoms and Signs of Disseminated and Late Lyme Disease
- Fatigue
- Multiple red rashes (EM’s)
- Severe headaches and neck stiffness
- Joint swelling and/or pain
- Neuropathic symptoms - nerve pain, numbness, hot/cold sensations, tingling
- Cognitive dysfunction
- Memory impairment
- Unprovoked pain which may interfere with sleep
- Palpitations or chest pain, shortness of breath
- Lightheadedness, fainting
- Gastrointestinal symptoms
- Psychiatric symptoms- including depression, anxiety, and mood changes