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Lyme Disease Basics for Providers

A Brief Primer by International Lyme and Associated Diseases Society

Epidemiology of Lyme Disease

Etiology of Lyme & Other Ixodes-Borne Illnesses

lyme disease


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 patients 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 patients 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

Diagnosis of Lyme Disease

Prophylaxis and Treatment