This document provides an overview of tick-borne infections including Lyme disease, anaplasmosis, ehrlichiosis, babesiosis, Powassan virus, and Rocky Mountain spotted fever. It discusses the epidemiology, ecology, clinical presentation, diagnosis, treatment and prevention of these infections. Key points include expanding ranges for ticks and infections, new diagnostic tests such as nucleic acid tests, similarities and differences between diseases, and recommendations for doxycycline treatment of most infections.
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Tick Borne Infections - MN
Daniel J Anderson, MD
Lyme
1,293 cases in 2010
(21 % increase from 2009)
Anaplasma
720 cases in 2010
( > 100 % increase from 2009)
Ehrlichia New species of Ehrlichia reported 2011
Babesia 56 cases in 2010 (31 in 2009)
Powassan
(50 cases in all of US 1958-2009 )
6 MN cases 2008 - 2010
1 MN death from Powassan 2011 (at ANW)
RMSF
2000 cases / year in all of US
Sporadic cases in MN
1 death in MN 2009
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http://www.health.state.mn.us/divs/idepc/diseases/lyme/highrisk.html
Risk of Tick-borne infection is not
uniform throughout the state.
The highest risk is central and SE
sections
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More Anaplasma than Lyme in
Aitkin, Beltrami, Cass, Crow Wing
& Hubbard counties
The risk of different tick-borne
infections also is not uniform
throughout the state
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Lyme
3-30 days after tick bite (BEFORE fever)
Erythema migrans (EM)
70 - 80 % of patients get rash
STARI
Very similar to Lyme disease
“expanding Bull’s Eye” lesions
RMSF
90 % -- usually 2 - 5 days AFTER fever
Initially small pink macules on wrists /
ankles
LATER petchial
Tularemia Skin ulcer w regional lymphadenopathy
RASH
Daniel J Anderson, MD
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Lyme
Pathogen. Borrelia burgdorferi (spirochete)
Clinical
EM rash, Bell’s palsy, AV block, CNS, Arthropathy
Co-infection -- ~ 5-10 % with Anaplasma || ~ 2 % with Babesia
Dx
IgM: HGA can cause false + IgM for Lyme
IgM can persist for years (even if no clinical disease)
After 8 weeks, should always have + IgG
Treatment -- no data for prolonged therapy
Prevention -- Doxycycline 200 mg if engorged tick < 72 h after bite
Daniel J Anderson, MD
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Lyme Diagnosis
Clinical diagnosis (ie no serology needed) if exposure to deer tick AND
Bilateral Bell’s Palsy
III ° AV block or complete heart block [CHB]
Characteristic erythema migrans [EM] rash
Daniel J Anderson, MD
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Lyme Serology
Criteria for positive
Western blot IgG ≥ 5 bands
Western blot IgM ≥ 2 bands
Chronology
Early IgM +
After 4-8 weeks
nearly all IgG + (regardless of RST test strain used)
SO, if IgG still negative > 8 weeks illness, then “+ IgM” is false +
IgM
HGA can cause false + IgM
+ IgM can persist for years ... may NOT correlate at all w clinical state
Daniel J Anderson, MD
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Lyme Testing:
Unvalidated tests with unproven use
Test assays whose accuracy and clinical usefulness have not been
adequately established. Unvalidated tests available as of 2011
include:
• Capture assays for antigens in urine
• Culture, immunofluorescence staining, or cell sorting of cell wall-
deficient or cystic forms of B. burgdorferi
• Lymphocyte transformation tests
• Quantitative CD57 lymphocyte assays
• “Reverse Western blots”
• In-house criteria for interpretation of immunoblots
• Measurements of antibodies in joint fluid (synovial fluid)
• IgM or IgG tests without a previous ELISA/EIA/IFA
Daniel J Anderson, MD
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Lyme PCR
Most useful for late arthritis if
done on synovial fluid
Limited use in CSF
Daniel J Anderson, MD
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Lyme Disease Treatment
Oral Therapy for all except neurological / late
arthritis or initially for high degree AV block
IV therapy: for meningitis, late arthritis or initially
for high degree AV block
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Lyme Disease Rx Duration
2-3 weeks for most early infections - tho’
some data suggest 10 days sufficient
2-4 weeks for meningitis / arthritis
4-8 weeks for late arthritis
Prolonged courses of therapy? .
No proven benefit
There are proven adverse consequences
(C diff, death, IV clots, ...)
Daniel J Anderson, MD
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Lyme Disease
Treatment
Reinfection rate rare (approximately 4 %)
Post Exposure Prophylaxis (PEP) -
single dose doxycycline 200 mg if < 72 hours
Daniel J Anderson, MD
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Human Granulocytic Anaplasomsis [HGA]
Pathogen Anaplasma phagocytophilum
Clinical
up to 35 % coinfected with Lyme and/or Babesia
fever, chills, headache, myalgia, and malaise,cough, diarrhea, confusion,
and lymphadenopathy,
17 % severe multisystem organ failure / SIRS / even death (Lyme does not
do this)
rash is not common
Data
leukopenia, thrombocytopenia,
mild hepatitis / transaminitis
Daniel J Anderson, MD
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Human Granulocytic Anaplasomsis [HGA]
Dx
Peripheral blood smear (in WBCs)
30 - 80 % + morulae
seen in granulocytes
Serology
NATs (PCR)
Treatment
Doxycycline (will also cover potential Lyme coinfection)
Daniel J Anderson, MD
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Human Monocytotropic Ehrlichiosis
[HME]
Pathogens
E canis / E chaffeensis / / E muris
Clinical
< 50 % with rash (but more often than with HGA)
More common farther south than Anaplasmosis (HGA)
Data -- Lymphopenia, morulae RARE on blood smear (vs HGA)
Dx -- Serology, PCR
Treatment - doxycycline
Daniel J Anderson, MD
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Anaplasmosis
HGA
Ehrlichiosis
HME
Farther north
MN & WI
Farther south
Iowa & Missouri
~ 50 % morulae
on blood smear
RARELY see
morulae in blood smear
rash is RARE
rash more common
(though still < 50 %)
serology / PCR
blood smear
serology / PCR
doxycycline doxycycline
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Babesiosis
Pathogen Babesia microtii (MN, WI, East coast), B divergens & B
duncani in other locations
Clinical
fatigue/weakness/malaise followed within days by fever
(>38° C) and one or more of the following: shaking chills,
sweats, headache, myalgia, arthralgia, and anorexia
Malaise, myalgia, arthralgia, and shortness of breath
differentiate babesiosis from other febrile illnesses
fatigue and malaise persist for several months
Daniel J Anderson, MD
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Babesiosis
Diagnosis
Blood smear (in RBCs)
Tetrad of ring forms
“Maltese Cross”
Serology
PCR
Treatment
Mild: atovaquone + azithromycin
Severe: clindamycin + quinine + exchange transfusion
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References
The Clinical Assessment, Treatment, and Prevention of Lyme
Disease, Human Granulocytic Anaplasmosis, and Babesiosis:
Clinical Practice Guidelines by the Infectious Diseases Society of
America. Clin Infect Dis. (2006) 43 (9): 1089-1134
http://cid.oxfordjournals.org/content/43/9/1089.full
National Institue of Allergy and Infectious Diseases. Tickborne
Diseases website.
http://www.niaid.nih.gov/topics/tickborne/pages/default.aspx