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A. Summary of Diseases [1]navigator

  1. Lyme Disease
    1. Borellia burgdorferi
    2. Ixodes Tick
    3. Northeast, Northern Mid-West, CA
  2. Tularemia (see below)
    1. Francisella tularensis
    2. Ticks: Dermacentor and Amblyomma
    3. Arkansas, Missouri, Oklahoma, Kansas
  3. Babesiosis (see below)
    1. Babesia ssp (protozoan)
    2. Ixodes Tick
    3. Northeastern States
  4. Relapsing Fever (see below)
    1. Borrelia recurrentis
    2. Ticks: Ornithodoros
    3. Western States
  5. Rocky Mountain Spotted Fever
    1. Rickettsia rickettsii
    2. Ticks: Dermacentor
    3. Southeast,West, South Central States
  6. Ehrlichiosis [4,5]
    1. Ehrlichia chaffeensis (monocytic) and E. phagocytophila or E. equi (granulocytic)
    2. Ticks: Dermacentor
    3. South Central, South Atlantic States
  7. Q Fever
    1. Coxiella burnetti
    2. Ticks: Dermacentor and Amblyomma
    3. Western States
  8. Colarado Tick Fever
    1. Coltivirus ssp (virus)
    2. Ticks: Dermacentor
    3. Western States
  9. Tick Paralysis (see below) [10]
    1. Due to a Neurotoxin
    2. Ticks: Dermacentor and Amblyomma
    3. Northwest and South
  10. Tick-borne encephalitis [2]
    1. Due to a flavivirus, tick-brone encephalitis virus
    2. Ticks: Ixodes
    3. Western Europe to Eastern Japan

B. Tulermia [8,9] navigator

  1. Organism
    1. Francisella tularensis (Types A and B, both found in North America and elsewhere)
    2. Gram negative, aerobic coccobaccilus
    3. Transmitted by ticks (Dermacentor and Amblyomma) to humans, carried from rabbits
    4. Also called "rabbit fever" or "deer fly fever"
    5. Transmission from rabbit carcasses has been described
    6. Aerosolized transmission can cause tularemia pneumonia or systemic illness
  2. Symptoms
    1. Painful, erythematous ulcer (60-80%) at site of initial skin lesion, and frank pus
    2. This form is called "typhoidal"
    3. Incubation 2-5 days with large tender, lymphadenopathy (lymphangitis may occur)
    4. Other symptoms include fever, chills, headache, cough, myalgia
    5. Uncommon meningitis, pericarditis, peritonitis etc. have been reported
    6. May also present as an atypical pneumonia or directly as systemic illness [8]
  3. Diagnosis
    1. Differential diagnosis should include causes of lymphangitis
    2. Tuleremia is only major cause of large, tender lymph nodes with associated skin ulcer
    3. Confirmed with serum agglutination titers (acute only) >1:160 titer (requires 2 weeks)
    4. ELISA tests are under development
    5. Rarely positive on Gram stains or blood cultures
  4. Treatment [8]
    1. Streptomycin 15mg/kg q12 hours IM for10-14 days OR
    2. Gentamcin 1.5mg/kg q8 hours IM for 10-14 days
    3. Tetracycline 500mg po qid x 14 days or Doxycycline are less effective
    4. Chloramphenicol is less effective than the aminoglycosides
  5. Prevention [8]
    1. Avoidence of exposure
    2. Vaccination of high risk populations with experimental vaccine (US Army)
  6. Mortality of untreated persons is 20-30%

C. Babesiosis [3,7]navigator

  1. Organisms
    1. Protozoan disease of animals transmitted by ticks (Ixodes)
    2. B. microti and B. divergens cause most human infections
    3. Found on Northeastern Coast of USA (Massachusetts, Connecticut and New York Islands)
    4. Infects erythrocytes
    5. More severe in patients with splenectomy and possibly with erythrocyte abnormalities
  2. Symptoms of B. microti Infection
    1. Gradual onset of fever, (shaking) chills, sweating and muscle pain
    2. Fatigue, malaise and weakness were most common
    3. Mild hepatosplenomegaly
    4. Mild hemolytic anemia
    5. May last weeks to months
    6. May be fatal disease in asplenic patients
  3. Symptoms of B. divergens Infection
    1. May have more severe illness than B. microti
    2. Chills, fever, nausea, vomiting, hemolytic anemia
    3. Severe disease with jaundice, renal failure, dyspnea (pulmonary infiltrates)
  4. Diagnosis
    1. Giemsa stained thick and thin blood smears
    2. Examine for small intraerythrocytic parasites
    3. B. microti similar to P. falciparum (small ring form)
    4. Immuofluorescence stains available
    5. Serology generally not useful; about 50% of patients may have Lyme Antibodies
    6. Polymerase chain reaction (PCR) for DNA in blood is sensitive and specific [6]
    7. Presence of Babesial DNA in blood predicts protracted duration of symptoms [6]
    8. Severe outcomes seen with increased alkaline phosphatase >125U/L and WBC >5.0K/µL
  5. Treatment
    1. B. microti infections in patients with intact spleens usually self-limiting
    2. Combination of quinine sulfate 650mg po tid and clindamycin 600mg po tid x 7-10 days
    3. Atovaquone 750mg q12 hours with azithromycin 500mg initially, 250mg qd thereafter for 7 days is as effective as and better tolerated than quinine + clindamycin [11]
    4. Intravenous agents can be used to treat severe parasitemia, especially in asplenia
    5. Babesial DNA can persist in blood in some patients treated with antibiotics [6]
    6. B. divergens may be treated by exchange transfusion, iv antibiotics, ± pentamidine
    7. All future anti-babesial drugs should be evaluated with babesial DNA testing in blood
    8. Red cell exchange should be carried out in high risk patients (>50 years, asplenia or other immunosuppression), or in complicated disease, or high (>10%) levels parasites [3]

D. Relapsing Fever navigator

  1. Caused by the spirochete Borrelia recurrentis or Borrelia crocidurae [13]
  2. Tick or louse borne
  3. Splenic disease may occur
  4. May cause epidemic disease, especially in wartime
  5. Occurs mainly in North Africa, west African Savanna, Middle East, some parts of Europe
  6. Treatment with antibiotics
    1. Penicillin, doxycycline and other tetracyclines are effective
    2. Treatment followed by fever, hypotension, rigors similar to sepsis syndrome
    3. This has been called the "Jarisch-Herxheimer" Reaction
    4. It is due to stimulation of white blood cells by bacterial (spirochete) products
    5. Tumor necrosis factor (TNF) plays a major role and antibodies to TNF reduce reaction
  7. Doxycycline 200mg x 1 then 100mg qd x 4 days completely (100%) blocked development of relapsing fever after tick bite / exposure in endemic area [12]

E. Tick Paralysis [10]navigator

  1. Caused by a neurotoxin secreted by ticks
  2. Neurotoxin Effects
    1. Reduces nerve conduction velocity
    2. Inhibits terminal-nerve conduction and acetylcholine release (presynaptic junctions)
    3. Causes total blockade of transmission at myoneural junctions
  3. Dermacentor and Amblyomma ticks cause disease in Northwest and South
  4. Much more common in children with ticks
  5. Adults appear less susceptible to neurotoxin and are heavier
  6. Can cause severe, permanent ascending paralysis
  7. However, if tick is removed early in disease course, complete recovery is possible
  8. Differential diagnosis includes variety of paralytic syndromes

References navigator

  1. Hilton E, DeVoti J, Benach JL, et al. 1999. Am J Med. 106(4):404 abstract
  2. Lindquist L and Vapalahti O. 2008. Lancet. 371(9627):1861 abstract
  3. Stowell CP, Gelfand JA, Shepard JO, Kratz A. 2007. NEJM. 356(22):2313 (Case Record) abstract
  4. Yawetz S and Mark EJ. 2001. NEJM. 345(22):1627 (Case Record)
  5. Medoff G and Murray PR. 1998. Am J Med. 104(6):600
  6. Krause PJ, Spielman A, Telford III SR, et al. 1998. NEJM. 339(3):160 abstract
  7. White DJ, Talarico J, Chang HG, et al. 1998. Arch Intern Med. 158(19):2149 abstract
  8. Drugs and Vaccines Against Biological Weapons. 1999. Med Let. 41(1046):15 abstract
  9. Franz DR, Jahrling PB, Friedlander AM, et al. 1997. JAMA. 278(5):399 abstract
  10. Felz MW, Smith CD, Swift TR, et al. 2000. NEJM. 342(2):90 abstract
  11. Krause PJ, Lepore T, Sikand VK, et al. 2000. NEJM. 343(20):1454 abstract
  12. Hasin T, Davidovitch N, Cohen R, et al. 2006. NEJM. 35592):148
  13. Vial L, Diatta G, Tall A, et al. 2006. Lancet. 368(9529):37 abstract