Quartz 5

Tickborne Illness

Properties1
aliasesTickborn, Lyme, RMSF

2 min read

quick reference

  • Suspect if:
    • Tick present or reported (esp. if attached >24hrs)
    • Classic Triad: Fever, Rash, Reported Tick Bite
    • CLINICAL DIAGNOSIS
      • Do not delay treatment for confirmatory assays

pathophysiology

  • All are tick vector-mediated bacterial/parasitic/viral infections

epidemiology / etiology


Geographically dependent

  • North Carolina MC:
    • RMSF (Rickettsia) and Ehrlichiosis
    • Surveillance for Vector-borne Illnesses:
      • Per North Carolina law (10A NCAC 41A .0101), clinicians are required to report confirmed or suspected cases of the tick-borne illnesses anaplasmosis, babesiosis, ehrlichiosis, rickettsiosis and Lyme disease.

clinical features

  • Symptoms of tick-borne diseases are often nonspecific, and may include:
    • Fever
    • Rash
    • Headache
    • Malaise
    • Nausea
    • Myalgia
      -Disease-specific findings:
    • Lyme:
      • Erythema migrans (bullseye rash) about 7-14 days after tick detaches
    • Babesiosis: None
    • RMSF:
      • Typically presents acutely with fever, headache, and maculopapular rash (occurring 2-4 days after fever and changing to petechial rash 5-6 days after fever) affecting palms and soles of feet.
      • Other symptoms may include malaise, abdominal pain and tenderness, anorexia, lethargy, photophobia, and nausea
  • Lab Findings:
    • T

diagnosis

  • CLINICAL DIAGNOSIS
    • Some tickborne illnesses have high mortality if left untreated
  • Confirmatory Assays
DiseaseLabNotes
Lyme disease (Borrelia burgdorferi)Two-tiered serologic testing:
1. ELISA (or EIA)
2. **Weste		For early localized disease (e.g. erythema migrans), diagnosis is clinical. Serology may be negative early.
Rocky Mountain Spotted Fever (Rickettsia rickettsii)Indirect Immunofluorescence Assay (IFA) for IgG antibody to R. rickettsiiBest if done on paired acute and convalescent samples (≥4-fold rise). Antibodies usually detectable after day 7.
Ehrlichiosis (Ehrlichia chaffeensis)PCR of whole bloodMorulae may be seen in monocytes (E. chaffeensis). IFA serology also confirmatory with 4-fold rise in titer.
Anaplasmosis (Anaplasma phagocytophilum)PCR of whole bloodBlood smear may show morulae in neutrophils, but low sensitivity. Serology (IFA) is confirmatory retrospectively.
Babesiosis (Babesia microti)Peripheral blood smear OR PCRSmear shows intraerythrocytic parasites (“Maltese cross” pattern); PCR is more sensitive, especially in low parasitemia.

treatment

  • When in doubt, Tick = Doxy
  • Exception:
    • Babesiosis= atovaquone plus azithromycin

other

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