Creepy, Crawly Killers
Tick-Borne Illnesses
Tick Identification
Lyme Disease

Transmitted by Ixodes scapularis “deer tick”
Borrelia burgdorferi

Most common vector-borne zoonotic
infection in the United States
Seasonal Variation

Most cases occur in the warmer months
◦ Outdoor activity is highest
◦ Nymph activity is at its peak
Stages: Primary

Symptoms:
7-10 days after bite

Erythema migrans:
80% of patients
Belt line, axillary,
inguinal, or popliteal
 25% report bite

Stages: Primary

Flu-Like Symptoms
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Fatigue (54%)
Anorexia (26%)
Myalgias (44%) and arthralgias (44%)
Fever (16%)
Regional lymphadenopathy (23%)
 Headache (42%), neck stiffness (35%)

◦ Meningeal findings absent, CSF studies
normal
Stages: Secondary
Rash can evolve
Stages: Secondary
Cranial neuropathy
 Meningoencephalitis
 Meningeal signs typically
absent
 CSF studies may be
positive

Stages: Secondary

Myopericarditis
Stages: Secondary

Atrioventricular block
Stages: Secondary

Rarely
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Conjunctivitis
Keratitis
Uveitis
Optic neuritis
Blindness
Stages: Tertiary
Months - Years after bite
 Joint complaints (usually larger joints)

 60% of untreated patients: monoarticular or
oligoarticular arthritis
 Exacerbations less frequent over years
Stages: Tertiary

“Lyme encephalopathy”
◦ Mood, memory, cognition, and sleep changes
Polyneuropathy
 Both have abnormal CSF studies

Diagnosis
Skin findings in endemic area
 ELISA IgG and IgM against Borrelia
(sensitivity of 89% and specificity of 72%)

◦ Many false-positives
◦ Positive or equivocal ELISA tests may be
confirmed with western blot
Treatment
Tick removed within 72 hours:
low likelihood of infection
 Tick attached for at least 36 hours:
consider treatment

Treatment: Primary + Secondary Stages

Doxycycline
◦ Adults: 100 mg BID for 14-21 days
◦ Children > 8 years: 1-2 mg/kg BID

Amoxicillin
◦ Pregnant or lactating: 500 mg TID for 14-21 days
◦ Children < 8 years: amoxicillin 50 mg/kg/day,
divided TID (max dose of 500mg/dose)
Treatment Exceptions
• Ceftriaxone
• Lyme Meningitis
• Severe cardiac disease
 Second or third degree heart block
 PR > 300 msec
 Symptomatic patients
Co-Infections

Babesiosis
◦ 2-40% of lyme patients

Human granulocytic anaplasmosis (HGA).
◦ 2-12% of lyme patients
Doxycycline does not treat babesiosis
 Amoxicillin does not treat HGA or
babesiosis
 Fever persists past 6 days: suspect coinfection

Babesiosis
Babesia species (especially microti)
 Transmitted by deer tick

Clinical Presentation
Flu-like illness: fever, chills, headache, fatigue,
and anorexia
 Splenomegaly
 More severe in splenectomized

◦ Severe hemolytic anemia, hemoglobinuria,
jaundice
◦ MOD: renal insufficiency, ARDS, and DIC
Diagnosis
Microscopy of thick and thin Giemsa
stains
 Antibody detection through IFA staining
 PCR

Treatment
With spleen: generally recover without
treatment
 Severe disease, splenectomized

◦ Clindamycin + quinine x 7-10 days OR
◦ Atovaquone + azithromycin x 7-10 days
Ehrlichioses

Human granulocytic anaplasmosis (HGA)
◦ Anaplasma phagocytophilum
◦ Black-legged tick
◦ Upper Midwest, New England, parts of the midAtlantic states, northern California

Human monocytic ehrlichiosis (HME)
◦ Ehrlichia chaffeensis
◦ Lone Star tick
◦ South central and South east

Ehrlichia ewingii
◦ South central
Clinical Presentation
Abrupt onset of flu symptoms: fever,
headache, myalgia, and shaking chills
 Can see GI: N/V, diarrhea, abdominal pain
 Rashes (HME>HGA)
 Meningitis
 Carditis
 MOD

◦ Renal failure
◦ DIC
◦ ARDS
Diagnosis
Clinical
 Leukopenia, thrombocytopenia
 Elevated LFTs

Acute and convalescent antibodies
 Enzyme immunoassay and Western blot
 PCR

Treatment
Doxycycline or tetracycline x 7–14 days
 Rifampin in children if concern for tooth
staining

Rocky Mountain Spotted Fever
Rickettsia rickettsii
 Southeastern United States
 American dog tick, Rocky Mountain wood
tick, common brown dog tick, Lone star
tick
 Frequently transmitted to humans by
dogs

Infection Cycle
Infect vascular endothelial cells and
vascular smooth muscle
 Cell-to-cell transfer via actin-based
motility
 Damaged endothelium with exposed
subendothelium, tissue plasminogen
activator, and von Willebrand's factor

Clinical Presentation

Vasculitis and thrombocytopenia
◦ Early rash
◦ Petechial and hemorrhagic lesions
◦ Microinfarcts

Small-vessel permeability
◦ Hypotension, edema, and increased
extravascular fluid
• Acute renal failure and hypovolemic shock
• Direct lung invasion: interstitial pneumonitis
Diagnosis
Clinical
 Immunofluorescent assay and
immunoperoxidase staining of R. rickettsii
in rash biopsies
 Serum antibody titer
 PCR
 Cell culture

Treatment

Doxycycline
◦ Including children!
• Chloramphenicol
 Pregnant women (except those near term)
 For significant contraindication to tetracyclines
• High-dose steroids in critically ill
Relapsing Fever

Epidemic (louse-borne)
◦ Borrelia recurrentis
• Endemic (tick-borne)
 Borrelia hermsii
 Borrelia turicatae
 Borrelia parkeri
• Mountain and Pacific states
 Elevations 2,000-7,000 ft with coniferous forest
Relapsing Fever
Rodent-Tick/Rodent-Louse life cycle
 Transmitted in infected saliva

Clinical Presentation
Febrile episode: ~ 3 days
 Asymptomatic period: ~7 days
 Relapse

◦ Antigenic variation
◦ Cycle repeats itself three to five times
◦ Successive relapses usually less severe
Diagnosis
Spirochetes on peripheral smear
 Genus-specific PCR tests from CDC
 Differential

◦ malaria, typhus, dengue, yellow fever,
Colorado tick fever, and tularemia
Treatment
Tetracycline or erythromycin
 33% have Jarisch-Herxheimer

◦ Approx. 4 hours after treatment
◦ Flu-like illness: fever, chills, headache, myalgia,
flushing
◦ Skin lesions
◦ Hypotension
Tularemia
Francisella tularensis
 Most common in Southwest
 Rodents, rabbits, prarie dogs
 Deer tick, the Lone Star tick, and the dog
tick
 Horse fly, and deer fly
 Infected food or water
 Inhalation of dust or water aerosol

Seasonal Variation
May to August: ticks
 December to January: hunting/skinning of
infected animals

Clinical Presentation

Ulceroglandular
◦ Most common form
◦ Inoculation site erythematous papule 
ulcerates 2 to 3 days later
◦ Regional lymphadenopathy and fever
Clinical Presentation

Glandular
◦ LAD (usually cervical) without skin ulcer.
◦ Oropharyngeal tularemia
 exudative pharyngitis with associated cervical
lymphadenitis
◦ Oculoglandular
 Unilateral conjunctivitis with regional adenopathy of
pre-auricular lymph nodes
Clinical Presentation

Typhoidal: systemic form with no obvious
entry site
◦ Fever, chills, constipation/diarrhea,
abdominal pain, and weight loss
◦ 30 to 60% mortality

Pulmonary
◦ Direct inhalation of aerosolized organisms or
bacteremic spread from another site
◦ Fever, chills, cough, substernal burning,
dyspnea
Bioterrorism
Category A
 Release of aerosolized particles

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3 to 5 days after exposure
Acute fever
Pneumonia
Pleuritis
Hilar lymphadenopathy
Diagnosis
PCR
 Do not culture bubo

◦ Notify lab personnel if you do
Treatment
Do not need patient isolation
 Streptomycin
 I&D residual sterile buboes after
completion of antibiotics
 Prophylaxis with doxycycline

Q Fever
Coxiella burnetii
 Cattle, sheep, goats
 Rocky Mountain wood tick
 Midwest states and California
 80% of cases in males
 Extremely resistant
 One organism can cause infection
 Category B biologic warfare agent

Clinical Presentation (Acute)
Fever (often 40° C or higher), myalgia
 Chest pain
 Atypical PNA
 Retrobulbar headache

Chronic
Granulomatous hepatitis
 Culture-negative endocarditis

◦ Up to 68% of patients with chronic Q fever
◦ Up to 25% mortality rate
◦ Usually a history of valvular heart disease
Diagnosis
Do not culture (risk to lab workers)
 ELISA assays

◦ Takes 2 - 3 weeks
Treatment
• Uncomplicated acute
 Doxycycline
• Acute disease with valvular disease
 Doxycycline + Hydroxychloroquine x 1 year
• Chronic
 Doxycycline + Hydroxychloroquine x 1.5 to 3 years
• Pregnant
 Long-term TMP/SMX
• Prophylaxis
 Doxycyline x 5-7 days
Colorado Tick Fever
Coltivirus
 Rocky Mountain area
 Rocky Mountain wood tick

Clinical Presentation
Flu-like: fever, chills, headache, myalgia,
lethargy, anorexia, and nausea
 Retrobulbar pain
 Biphasic course : “saddleback” fever curve

◦ Sick for 2 - 3 days
◦ Well for 1 - 2 days
◦ Sick 2 - 4 days
Diagnosis
Immunofluoroescence
 PCR

Treatment
Almost always self-limited
 Supportive treatment

Tick Paralysis
Adult female tick
 Releases a neurotoxin that causes
cerebellar dysfunction, ascending
paralysis
 Southeastern and northwestern regions
of the United States
 47 tick species: most common Rocky
Mountain wood tick and American dog
tick

Mechanism

Ixobotoxin stops sodium flux across
axonal membranes  loss of acetyl
choline release at neuromuscular junction
Clinical Presentation
Restlessness and irritability
 Ascending flaccid paralysis +/- acute ataxia

◦  bulbar involvement, respiratory paralysis,

https://www.youtube.com/watch?v=24DZ
EaUN7cc
Treatment
Tick removal
 Improvement in hours
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References
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http://www.cdc.gov/ticks/diseases/
Cline D, Ma OJ, et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 6th
edition. McGraw-Hill, 2004
Dudley, J P (2010), “Tularemia: A Case Study In Medical Surveillance And Bioterrorism
Preparedness”, JMedCBR 8, 17 September 2010,
http://www.jmedcbr.org/issue_0801/Dudley/Dudley_09_10.html.
Halperin JJ. Prolonged Lyme disease treatment: enough is enough. Neurology 2008;70:986
http://www.michigan.gov/emergingdiseases/0,4579,7-186-25890-75870--,00.html. Accessed
9/27/15.
Nadelman RB, Nowakowski J, Forseter G, et al. The clinical spectrum of early Lyme
borreliosis in patients with culture-confirmed erythema migrans. Am J Med 1996; 100:502
Rosen's emergency medicine: concepts and clinical practice 7th edition. Philadelphia, PA:
Mosby/Elsevier; 2010.
Steere AC, Schoe RT,Taylor E. The clinical evolution of Lyme arthritis. Ann Intern Med
1987; 107:725
Wolfson A, Hendey GW, et al. Harwood-Nuss’ Clinical Practice of Emergency Medicine,
5th edition. Philadelphia: Lippincott Williams & Wilkins and Wolters Kluwer Business, 2010.
Wormser GP. Clinical Practice Early Lyme Disease. N Engl J Med 1996; 354:2794.