Tick-borne Infections. Pola de la Torre, M.D. Assistant Professor of Medicine Division of Infectious Diseases. Ticks. Blood-sucking arthropods (eight legged) of the class Arachnida. Three families: -Ixodidae (hard ticks) -Argasidae (soft ticks)
Pola de la Torre, M.D.
Assistant Professor of Medicine
Division of Infectious Diseases
-Ixodidae (hard ticks)
-Argasidae (soft ticks)
-Nuttalliellidae (characteristics of both)
-Larvae: August and September.
-Nymphs: May through July.
-Adults: Spring and Fall.
without leaving the mouth parts in the skin.
-Nonmotile pleomorphic weakly gram-negative
- Intracellular obligate that resides more
in the cytosol (less so in the nucleus) of
-Can be seen with Gimenez or acridine
-Two thirds of US and the Far West
-Interstitial pneumonia, interstitial
myocarditis, perivascular glial nodules of
the CNS and similar vascular lesions in
the rash, GI tract, pancreas, liver,
skeletal muscles, and kidneys.
-Small fraction on the first day.
-49% during the first 3 days.
-Usually appears 3-5 days after the onset
of fever and occurs in 84-91% overall.
appears late and although thought to be characteristic occurs in only 36-82% with
-Without appropriate therapy death occurs
8-15 days after onset of symptoms.
-Labs nonspecific: WBC generally WNL
but with increased immature myeloid
cells, anemia in 5-30%, thrombocytopenia,
coagulopathy is infrequent.
-Hyponatremia in 50%.
-Increased LDH, CK, other enzymes related to diffuse tissue injury.
-Death within the first 5 days
Antibodies haven’t developed
Characteristic lesions appear different
-Black males with G6PD deficiency, older
age, possibly alcoholism.
clinical and epidemiologic.
rubella, respiratory tract infection,
gastroenteritis, acute abdomen,
enteroviral infection, meningococcemia,
disseminated GC, secondary syphilis,
leptospirosis, immune complex vasculitis, ITP,
TTP, EBV, drug reaction, ehrlichioses, other
-A fourfold increase in titer between acute
and convalescent stages is diagnostic.
-A titer of ≥64 detectable between 7 and
10 days after the onset of illness.
after the patient has become afebrile.
-About 70-80% develop EM (expands slowly at 1 cm/day) at the site of the bite.
-Most patients do not remember the bite
because the small size of the nymphal I.
-Within several days to weeks of the
onset of EM, may develop multiple
annular secondary lesions.
-Some develop malar rash, conjunctivitis,
or, rarely, diffuse urticaria.
-These lesions usually fade within 3-4
weeks (1 day -14 months).
-EM is often accompanied by malaise,
fatigue, HA, F, C, generalized achiness,
and regional lymphadenopathy.
-In 18% these symptoms are the
-Some may have evidence of meningeal
irritations: HA, neck pain, mild
-Meningitis, encephalitis, cranial neuritis
(including bilateral facial palsy), motor
and sensory radiculoneuritis, mononeuritis multiplex, cerebellar ataxia or myelitis.
-Lymphocytic pleocytosis of ~100 cells
-Often elevated protein
-Most common: fluctuating degrees of
-Mild LV dysfunction
-Months after the onset of disease
-~60% begin to experience intermittent
attacks of joint edema and pain primarily
in the large joints.
-Attacks of arthritis usually last from
weeks to months separated with periods
WBC’s most of which are polys.
attacks may be longer and chronic arthritis develops in ~10% of untreated patients (≥1 year of continuous joint
or intermittent arthritis usually resolves
completely within several years.
-Chronic axonal polyneuropathy
No inflammatory changes in the CSF, but
intrathecal antibody production.
-Migratory M-S pain is common.
-Osteomyelitis, myositis, panniculitis,
-Conjunctivitis the most common eye
-Two of three: 23, 39, 41.
A combination of 23 and 41 may still be a false
-Five of ten: 18, 32, 38, 30, 41, 45, 58, 66, 93.
-The attached tick can be identified as an
adult or nymphal I. scapularis that is
estimated to have been attached for ≥36
hours based on the degree of
engorgement of the tick with blood or of
certainty about the time of exposure to
-Prophylaxis can be started within 72 hours of the time that the tick was removed.
-Ecologic information indicates that the rate of infection of these ticks with B. burgdorferi is ≥20%.
-Doxycycline is not contraindicated.
-Doxycycline 100 mg bid x 14-21 days
-Amoxicillin 500 mg tid x 14-21 days
-Cefuroxime axetil 500 mg bid x 14-21 d
-Erythromycin 250 mg qid x 14-21 days
-Doxycycline 100 mg bid x 30-60 days
-Amoxicillin 500 mg qid x 30-60 days
-Ceftriaxone 2 g qd x 14-28 days
-PCN G 20 million U IV qid 14-28 days
-Ceftriaxone 2 g qd x 14-28 days
-PCN G 20 million U IV qid x 14-28 days
-Doxycycline 100 mg tid x 14-28 days
-Oral regimens may be adequate
-First degree AV block: oral
-High degree AV block:
Ceftriaxone 2 g qd x 14-21 days
PCN G 20 million U IV qid x 28 days
->50 years of age
-Acute respiratory failure
-~20-30% have positive responses of the
-Clindamycin 300-600 mg q 6 hours +
quinine 650 mg q 6-8 hours for 7-10
-Atovaquone 750 mg bid + azithromycin
500mg followed by 250 mg qd.
Human Monocytotrophic Ehrlichiosis
-Nausea, vomiting, anorexia, weight loss.
-Cough, diarrhea, confusion, lymphadenopathy.
-ARDS, ARF, CNS abnormalities,
coagulopathy, GI hemorrhage, death.
-Lymphocytosis, increased protein, may
demonstrate infected cells.
Human Granulocytic Anaplasmosis
infected blood has been reported.
Average annual incidence of anaplasmosis (caused by Anaplasma phagocytophilum) by state, as reported to CDC, 2001--2002