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Deer Tick
Aka: Deer Tick, Black Legged Tick, Ixodes Scapularis, Ixodes pacificus, Antibiotic Prophylaxis After Known Deer Tick Bite
- See Also
- Tick-Borne Disease
- Vector Borne Disease
- Lyme Disease
- Babesiosis
- Human Granulocytic Anaplasmosis (HGA)
- Pathophysiology
- Deer Tick (Ixodes Scapularis) Image derived from CDC

- Deer Ticks have four stage life cycle over 2 years
- Egg
- Larva
- Nymph (most common form to transmit disease)
- Adult
- Transmission of disease
- Transmission unlikely before attached for 1-2 days
- Engorged nymph most likely to transmit disease
- Pathophysiology: Diseases transmitted by the Deer Tick
- Lyme Disease (Borrelia Burgdorferi)
- Human Babesiosis (Babesia Microti)
- Human Granulocytic Anaplasmosis (HGA)
- Previously known as: Human Granulocytic Ehrlichiosis
- Organism name
- New: Anaplasma phagocytophila
- Prior: Ehrilichia phagocytophila
- Differential Diagnosis
- American Dog Tick (Dermacentor variabilis)
- Twice the size of Deer Ticks
- Not associated with Lyme Disease
- Associated with Babesiosis
- Management: Deer Tick Bite
- Prompt Tick Removal
- See Tick Removal
- Infection transmission 1% at under 24 hours
- Infection transmission 20% at over 72 hours
- Observe for Tick Borne Illness for 30 days after bite
- Erythema Migrans (Lyme Disease)
- If fever occurs, consider additional conditions
- Babesiosis
- HGA (previously known as Ehrlichiosis)
- Antibiotic Prophylaxis After Known Deer Tick Bite
- Routine prophylaxis not recommended
- Following known deer Tick Bite in endemic area
- Early Lyme DiseaseIncidence: 1.2%
- Antibiotics after deer Tick Bite in endemic area
- Doxycycline
- Dose within 72 hours of Tick Bite
- Adults: 200 mg orally for one dose
- Child >8 years: 4 mg/kg (max: 200 mg) orally for one dose
- Efficacy in preventing Lyme Disease: 87%
- References
- Nadelman (2001) N Engl J Med 345:133-4 [PubMed]
- No other antibiotic is indicated in prophylaxis
- Prior study showed some efficacy with Amoxicillin
- Shapiro (1992) N Engl J Med 327:1769 [PubMed]
- Prevention
- See Prevention of Vector-borne Infection
- Resources
- CDC Lyme Disease
- http://www.cdc.gov/ncidod/dvbid/lyme/index.htm
- Iowa State Deer Tick Home Page
- http://www.ent.iastate.edu/imagegallery/ticks/