II. 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
III. Pathophysiology: Diseases transmitted by the Deer Tick
- Lyme Disease (Borrelia Burgdorferi)
- Human Babesiosis (Babesia Microti)
-
Human Granulocytic Anaplasmosis (HGA, Anaplasma phagocytophila)
- Previously known as: Human Granulocytic Ehrlichiosis (Ehrilichia phagocytophila)
IV. Differential Diagnosis
- American Dog Tick (Dermacentor variabilis)
- Twice the size of Deer Ticks
- Not associated with Lyme Disease
- Associated with Babesiosis
V. Management: Deer Tick Bite
- Prompt Tick Removal
- See Tick Removal
- Borrelia Burgdorferi infection transmission 1% at under 24 hours
- Borrelia Burgdorferi 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 is not recommended outside of Lyme Disease endemic areas
- 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
- Dose within 72 hours of Tick Bite
- No other Antibiotic is indicated in prophylaxis
- Prior study showed some efficacy with Amoxicillin
- Doxycycline
VI. Prevention
VII. Resources
- CDC Lyme Disease
- Iowa State Deer Tick Home Page