Rita

********************************

Dr Donta has given me permission to send this article to you in it's
entirety.  You can find the article in Med Clin North Am 2002
Mar;86(2):341-9, vii.  It was sent to me in a Word document, so I have had
to do a little reformatting to get it to look clean in my email client.  (I
hope it will also looks clean in yours!)  I have not altered anything other
than to remove page numbers and change the margins a bit.

-Robynn
********************************

LATE AND CHRONIC LYME DISEASE
Sam T. Donta, MD*

* Professor of Medicine, Divisions of Infectious Disease and BioMolecular
Medicine
Director, Lyme Disease Unit
Boston University Medical Center, Boston, Massachusetts

Corresponding author for proof and reprints:
Sam T Donta MD
Boston Medical Center
650 Albany Street-8th floor
Boston MA 02118
(617) 638-6017
(617) 638-6009 (fax)
sam.do...@bmc.org  (email)

INTRODUCTION

Following the introduction of Borrelia burgdorferi into the skin by an
infected tick, the organisms begin to spread both locally and systemically.
Several days typically elapse before the appearance of the first sign of
infection, i.e. erythema chronicum migrans (ECM), or other less typical
rashes (29).  The rash occurs in fewer than 50% of patients with Lyme
Disease (8,10), but the true incidence of Lyme Disease in the absence of a
rash is unknown.

The occurence of multiple rashes is indicative of systemic spread of the
organisms.  Multiple rashes usually do not occur until 2-4 weeks following
the initial tick bite.  This is the same time period during which the
organisms are being disseminated to their target tissues and cells.  The
incidence of multiple rashes was initially reported to occur in as many as
50% of cases, but has been much less common in the last two decades,
probably because of frequent use of antibiotics.

Approximately 4-6 weeks following the tick bite, the first systemic symptoms
(other than multiple rashes) occur in some patients, usually in the form of
"flu" (15). These symptoms include sore throat, severe headaches and neck
aches, and severe fatigue.  Rhinitis, sinusitis, and cough are not usually
present, distinguishing this "flu" from other influenza-like illnesses.
While the Lyme-flu symptoms can spontaneously resolve, patients can
experience recurrent "flu".

Soon after the onset of Lyme-flu, fatigue, arthralgias and/or myalgias may
begin.  The arthralgias appear to primarily involve the large joints (i.e.
knees, elbows, hips, shoulders), although smaller joints (e.g. wrists,
hands, fingers, toes) may be involved (29).  Some patients may have actual
arthritis, often oligoarticular, more frequently in men than in women.
Earlier estimates were that 50-75% of patients who developed late Lyme
Disease had arthritis, but more recent analyses suggest that the incidence
of actual arthritis in patients with late or chronic disease is closer to
25% (33).  Neck stiffness is common. The pains are described as severe,
jumping from joint to joint, and may be present for only short periods of
time. Pain in the teeth or in the temporal-mandibular joints is not
uncommon.  Rib and chest pains occur frequently, leading some patients to
seek care in emergency rooms and urgent care centers for evaluation of
possible cardiac disease.  Frequently as well are paresthesias such as
burning, numbness and tingling, and itching.  Some patients experience
crawling sensations, vibrations, or electric shock-like sensations.  Rarely
is there any actual palsy of the affected areas, making this much more of a
neurosensory, rather than a motor, disease.

In addition to paresthesias, purely neurological symptoms and signs include
headaches, an aseptic meningitis, facial nerve (Bell's) palsy, and
encephalitis or encephalopathy that may be manifested by cognitive
dysfunction, especially short-term memory loss, and psychiatric symptoms
such as panic, anxiety, or depression (14).  The aseptic meningitis and
Bell's palsy tend to occur within the first few months following the tick
bite, but may also occur as part of reactivation disease (9).

Other symptoms may include fevers (usually low grade, but may be high),
sweats (which may be severe), visual dysfunction (described primarily as
blurriness, but can include optic neuritis or uveitis), tinnitus,
sensitivity to sounds, or hearing loss.  Shortness of breath, palpitations
and/or tachycardia, abdominal pains, diarrhea or irritable bowel, testicular
or pelvic pain, urinary frequency or urgency, dysequilibrium, and tremors
are also common symptoms. Some of the dysautonomia symptoms can be
disabling.  Rarer symptoms may relate to panniculitis and hepatitis.  Rarely
as well are congenital and intrautero infection; when this occurs, it
appears to be similar to toxoplasmosis and rubella, i.e. a primary infection
during the first trimester.  The occurrence of optic neuritis or uveitis
raises other possibilities such as multiple sclerosis, but can be part of
Lyme Disease.

The course of the disease can best be described as persistent, but with
periods of worsening symptoms, often cyclical every few weeks or monthly.
Especially disconcerting are persistent symptoms such as headaches and
fatigue that can be exhausting.  Some patients are more symptomatic than are
others, which may reflect genetically-determined differences in
responsiveness or extent of infection.  The disease does not appear to be
progressive or destructive, as with cancer, nor is it fatal, but can be very
debilitating.

The incidence of asymptomatic infection has not been adequately delineated.
There appear to be substantial numbers of patients who remain asymptomatic,
but reactivate their disease a number of months or years later, following
trauma, pregnancy, a medical illness for which an antibiotic is prescribed,
or other stresses, including psychological stresses (9).  The Lyme OspA
vaccine has appeared to reactivate Lyme Disease in a number of individuals
who knew, but some who did not know, they had prior Lyme Disease (11).  The
mechanisms responsible for  the reactivation of the disease have not been
defined, but may include both molecular mimicry and underlying infection.

PATHOGENESIS

The pathogenesis of Lyme Disease remains to be defined.  From the available
studies, it would appear that the organisms are trophic for either the
endothelial cells of the blood vessels that serve the nervous system or for
the glial or neural cells themselves (4,24,26,31).  Accumulating evidence
supports the hypothesis of a persistent infection as the cause of the
persisting or relapsing symptoms (26,31).  Whether molecular mimicry is
involved in the pathogenesis of some of the symptoms remains more
speculative (18). Although arthritis can occur in Lyme Disease, the
organisms can only rarely be found in synovial tissue.  And as many of the
arthralgias that occur in the disease do not respond well to
antiinflammatory agents,  the disease is more of an infectious neuropathy
than an actual invasion of synovial or bursal tissues.

DIAGNOSIS

The diagnosis rests heavily on the clinical symptomatology.  When there are
clinical signs, e.g. rash, aseptic meningitis, optic neuritis, arthritis, an
appropriate differential diagnosis must be pursued.  On a clinical basis,
"chronic fatigue syndrome" or "fibromyalgia" cannot be readily distinguished
from chronic Lyme Disease.  Indeed, accumulating experience suggests that
Lyme Disease may be a frequent cause of fibromyalgia or chronic fatigue
(8,12).  Other microbes have been proposed as causative agents of
multisymptom disorders that are being termed chronic fatigue and
fibromyalgia, especially more recently recognized mycoplasma species such as
M.fermentans and M.genitalium, but definitive proof of cause and effect has
not yet been established (6, 23).

There has been an attempt to separate “late” Lyme Disease from
“chronic”
Lyme Disease, the former being manifested by objective signs of arthritis or
neurological disease (32). Some have denied the existence of chronic
disease, inferring that these patients suffer from psychiatric disorders;
some have used the term “chronic” to mean post-treatment disease
 (“post-Lyme”), assuming that the infection has been treated, and the
remaining symptoms are in the same realm as those patients who have
“fibromyalgia” or “chronic fatigue” (27, 30).  These assertions are
speculative and remain unproven.  That chronic Lyme Disease actually exists,
and is likely the most common form of the disease, is supported by
epidemiologic studies demonstrating that 30-50-% of treated and untreated
patients go on to develop a multisymptom disorder typical of, and
indistinguishable from, fibromyalgia and chronic fatigue (1, 28). As with
other multisymptom disorders, chronic Lyme Disease is a clinical syndrome
consisting of fatigue, arthralgias and myalgias, and other nervous system
dysfunction (7).  Furthermore, the results of treatment studies appear to
support the hypothesis that persistent infection is responsible for the
chronic symptoms.  It is likely that Lyme Disease will serve as a useful
model for other chronic multisymptom disorders.  Whether the pathogenesis of
“late” Lyme Disease differs from that of the chronic form of the disease
remains to be established.

Routine laboratory tests are usually normal in Lyme Disease. The ESR is most
often normal, distinguishing it from some of the inflammatory disorders such
as rheumatoid arthritis or lupus.  Culture of the borrelia is possible early
in the disease, usually from biopsies of the erythema migrans rash;
however, most laboratories are not capable of culturing the organisms.

The only currently available useful laboratory tests are the
immunologically-based ELISA and Western blot assays.  The recommendation was
made in 1994 to have a two-tiered testing system in which the Western Blot
would only be done on ELISA-positive samples (5).  The recommendation was ba
sed primarily on the results obtained from patients with arthritis (13), did
not take into account the chronic form of the disease, and was made despite
the lack of consistent reproducibility of results between various
laboratories (2, 16).  The ELISA has been shown to be an unreliable test in
many patients with Lyme Disease, both in early infection and later disease
(8, 10).  Part of the reason for the lack of sensitivity of the ELISA is the
use of whole organisms, resulting in a high amount of background absorbance.
After correction for the high background, only a small percentage of
positives can be detected. Because Western blots separate the proteins of
the borrelia, specific reactions can be visualized, and more accurate
interpretations of the results made.  Over 75% of patients with chronic Lyme
Disease are negative by ELISA, while positive by Western blot (8, 10).
Patients with oligoarticular arthritis may be more likely to have robust IgG
responses and positive ELISA tests and IgG Western Blots (13).

By Western blot analyses, the first immunologic reactions in Lyme Disease
are to the 41kd flagellar protein, and the 23kd OspC protein. Typically, at
the time of the ECM rash, there will be an IgM reaction against the 23kd and
41kd proteins, and no IgG reactions.  Within the next few weeks, the IgM
reactions persist, sometimes accompanied by less specific reactions against
60kd and 66kd proteins, and IgG reactions are now visible against the 23kd
and 41kd proteins.  Thus, in the presence of an appropriate clinical
picture, the immunoreactivity against the 23kd and 41kd proteins appear to
be diagnostic of Lyme Disease.

Whereas the 41kd protein is not unique to B. burgdorferi, the 23kd protein
appears to be unique.  Also apparently unique proteins of B.burgdorferi are
the 31kd (Osp A) and 34kd (Osp B) outer membrane proteins, and the 35kd,
37kd, 39kd, and 83/93kd proteins.  Reactions to the 31kd proteins are not
usually seen until after a year or more following the onset of disease.  Not
all patients with symptoms for more than one year, however, display
reactions to the outer membrane proteins.

Most symptomatic patients have specific reactions on IgM Western blots
(8,10).  With resolution of the symptoms, the IgM reactions disappear or
attenuate.  IgG reactivity may continue to be present with resolution of
symptoms, but it typically also disappears or attenuates with successful
therapy.  There are some patients (20%) who have symptoms, but whose Western
blots are negative (8,10).  If the borrelial organisms remain intracellular,
with no extracellular reemergence once established, this could explain the
absence of additional or persistent immune responses.

PCR (Polymerase Chain Reaction) is a highly sensitive means to detect
microbial DNA or RNA, and it was hoped that this technique would find an
important role in the diagnosis of Lyme Disease.  Thus far, however, despite
the specificity of this method, borrelial DNA or RNA has not been reliably
detected in the blood, urine, or spinal fluid of patients with early or
later forms of Lyme Disease, findings again supportive of an intracellular
reservoir for the borrelia.

It should be possible to develop a better, highly specific ELISA for Lyme
Disease, using recombinant 41kd, 23kd, 31kd and/or 34kd (and perhaps other
B.burgdorferi-specific) proteins.  Currently, however, the Western blot
assay is the most reliable immunologic test.

TREATMENT

In vitro, B. burgdorferi is sensitive to several antibiotics (20,25).  This
assumption is complicated, however, because of the long incubation times
needed to determine minimum inhibitory concentrations (MIC), as the borrelia
have doubling times of 20-24 hrs.  With these limitations, the results of a
few studies show minimum bactericidal concentrations (MBC) to penicillin of
8ug/ml, ampicillin: 2ug/ml, tetracycline: 1-2ug/ml, doxycycline: 2ug/ml,
ceftriaxone: 0.5ug/ml, cefotaxime: 0.5ug/ml, cefuroxime: 1-2ug/ml, cefixime:
8ug/ml, erythromycin: 0.5ug/ml, clarithromycin: 0.5ug/ml, azithromycin:
0.5ug/ml, and ciprofloxacin: 4ug/ml.

At the time of the first rash, any one of several antibiotics appear to be
effective, if given for 2 weeks, according to several published studies.
However, a number of patients so treated developed subsequent symptoms of
arthralgias, fatigue, and paresthesias, with positive Western blots, who
were then successfully treated with longer courses of antibiotics (8, 10).
The recommendation at this time, therefore, is that tetracycline,
doxycycline, or amoxicillin be used for 1 month if ECM is the only symptom
of Lyme Disease.

Once any other symptoms appear, the treatment of Lyme Disease for only 2-4
weeks is associated with frequent failures and relapses (8, 10).  Our
initial experience suggested that a 3 month course of tetracycline was
associated with a higher success rate (8).  In patients with symptoms
present for more than six months, the treatment course may need to be more
prolonged, or a retreatment course of varying length may be needed.  In
patients with symptoms for more than a year, 12-18 months may be needed for
complete resolution of symptoms.  The rationale for a longer treatment
course is based on extensive observations (8,10), plus the analogy to the
longer treatment courses required for tuberculosis, leprosy, Q fever, and
certain fungal diseases.  With Lyme Disease, the slow growth rate and
metabolic activity of the borrelia would seem to correlate with the need for
longer treatment periods.

Once treatment is initiated for patients beyond the earliest signs of
infection, their symptoms frequently increase during the first several days,
or even for the first several  weeks of therapy.  For patients with
preexisting symptoms of more than a few months, relief of any of their
symptoms may not occur until after 4-6 weeks of therapy (8, 10).  Typically,
there are short periods of relief, followed by relapsing or migrating
symptoms; with continued therapy there are longer symptom-free periods.
Some arthralgias may require 3 months or more to resolve, and fatigue may be
the last symptom to disappear.

The preference for tetracycline evolved because of the large number of
failures that were noted in patients who had been on ampicillin and
doxycycline. Patients generally had some response to doxycycline, but it was
uaually not complete, nor long-lasting.  Tetracycline may be more effective
than doxycycline simply because of the greater dose, i.e., 100mg of
doxycycline twice daily is not equivalent to 500mg of tetracycline three
times daily; also, doxycycline is highly protein-bound, compared to
tetracycline, which could limit the availability of free drug to diffuse
into tissues and cells.  Some physicians use doxycycline at doses of
300-400mg daily to try to achieve a successful result.  A strict comparison
between doxycycline and tetracycline has not yet been made. Minocycline has
also been used by some physicians, with varying success, but faces the same
issues of dosage and protein binding.

Of the beta lactams used for the treatment of Lyme Disease, the most
efficacious appears to be ceftriaxone.  In limited comparitive trials,
cefotaxime appears to be equally efficacious, and high-dose IV penicillin
may also be effective.  In early Lyme Disease, oral amoxicillin is as
effective as doxycycline.  In later disease, many failures are noted,
despite the use of up to 3 grams of amoxicillin daily, with probenicid.
Cefixime would also not appear to be effective therapy.  Cefuroxime axetil
has been evaluated only in the treatment of early Lyme Disease, and appears
comparable to doxycycline.  Limited reports of its use in later Lyme Disease
have not shown it to be efficacious.

The role of the newer macrolides in the treatment of Lyme Disease needs
further assessment.  Erythromycin has been regarded as ineffective, despite
its good in vitro sensitivities.  Azithromycin has been reported to be less
effective in the treatment of early Lyme Disease than amoxicillin (21).
Some physicians use clarithromycin and azithromycin in higher dosages and
for longer periods of time, but there have been no reports of greater
success with these drugs than with the tetracyclines or beta-lactams.  In
our experience, all macrolides are effective when combined with a
lysosomotropic agent, especially hydroxychloroquine (see below) (10).

In evaluating the possible factors, it would appear that antibiotics that
can achieve intracellular concentrations and activity are the most
efficacious drugs.  The results of studies in Klempner’s laboratory using a
tissue culture model of borrelia infection demonstrated that ceftriaxone was
incapable of eradicating intracellular organisms (17); similar experiments
in Raoult’s laboratory using an endothelial cell model demonstrated that
tetracycline and erythromycin were effective, but beta lactam antibiotics
were not (3).   These results are in line with our experience that the
tetracyclines and macrolides achieve the greatest success.  In contrast to
beta lactams, antibiotics of the tetracycline and macrolide classes are
capable of good intracellular penetration. Experience with the macrolide
antibiotics has been disappointing, however, when compared with its in vitro
activities against the Lyme borreliae, and with the established efficacy of
macrolides against other intracellular parasites such as chlamydia,
legionella, mycobacterium-avium intracellulare, and toxoplasma.  If, though,
the Lyme borreliae reside in intracellular vesicles that are acidic, the
macrolides’ activity would be sharply decreased at the lower pH.  This is in
contrast to the tetracyclines, which are active at acid pH; even so, the
activity of doxycycline was shown to be further increased by increasing the
pH.  In a tissue culture model of ehrlichia infection, the use of
lysosomotropic agents such as amantidine, NH4Cl, and chloroquine increased
the killing of intracellular organisms by doxycycline (22).  Based on those
studies, and the hypothesis that late Lyme Disease symptoms are due to
persisting intracellular infection, we have been successfully treating
patients using the combination of a macrolide and hydroxychloroquine (10).

As regards "CNS" disease, there is no evidence that ceftriaxone is more
successful than either the tetracyclines or the combination of macrolide and
hydroxychloroquine; if our presumption that the pathogenesis of the disease
involves the localization of the borrelia to the endothelial cells of the
blood vessels serving the nervous system or to glial or neural cells is
correct, then one would not need to have a drug that can cross the
blood-brain barrier to be effective.  Indeed, the tetracyclines can cross
the blood-brain barrier to some extent, and were used when initially
introduced into clinical medicine for the treatment of meningitis, with some
success.  Macrolide antibiotics do not cross the blood-brain barrier, but
have been effective in treating other CNS infections (eg toxoplasmosis), and
in our experience have been effective in reversing the neuropsychiatric
symptoms and signs (eg SPECT scans) of Lyme Disease (10).  With regard to
the issue of  bactericidal vs bacteristatic effects, any such effect in vivo
has not been demonstrated.  Finally, there have been no reports showing any
change in antibiotic resistance patterns during the course of treatment.
Ultimately, the determination of efficacy of therapy depends on the clinical
response.

FUTURE DIRECTIONS

The diagnosis and treatment of Lyme Disease have been hampered by less than
adequate diagnostic tests and inadequate comparisons of antibiotic regimens.
Specific antigen-based ELISA tests should result in greater specificity, but
sensitivity of any tests based on measurements of the host immune response
might still be of limited value if the borrelia remain intracellular. Most
useful would be the development of tests that can determine the presence and
extent of any residual borreliosis.  In the therapy of Lyme Disease,
double-blind, placebo-controlled and comparitive trials are needed to answer
the questions relating to duration and class of antibiotic therapy.  The
apparent failure of a regimen of one month of IV ceftriaxone, followed by
two months or oral doxycyline, to improve the outcomes of patients with
chronic Lyme Disease (19) was not surprising, based on prior observations
that neither regimen used for a limited duration was capable of yielding
patient improvement (8,10,33).  Additional trials are needed to evaluate
whether longer durations of treatment, using tetracycline itself, or the
novel combination of macrolide and lysosomotropic agent, would be proven
effective treatments.

 REFERENCES

1. Asch ES, Bujak DI, Weiss M, et al. Lyme Disease: an infectious and
postinfectious syndrome.  J Rheum 21:454-61, 1994.

2. Bakken LL, Case KL, Callister SM, et al. Performance of 45 laboratories
participating in a proficiency testing program for Lyme Disease serology.
JAMA 268:891-5, 1992.

3. Brouqui P, Bodiga S, and Raoult D. Eucaryotic cells protect Borrelia
burgdorferi from the action of penicillin and ceftriaxone but not from the
action of doxycycline and erythromycin. Antimicrob Agents Chemother
40:1552-4, 1996.

4. Cadavid D, O’Neill T, Schaefer H, and Pachner AR. Localization of
Borrelia burgdorferi in the nervous system and other organs in a nonhuman
primate model of Lyme disease. Lab Investigation 80:1043-54, 2000.

5. Centers for Disease Control. Recommendations for test performance and
interpretation from the Second National Conference on Serologic Diagnosis of
Lyme Disease.  MMWR 44:590-1, 1995.

6. Choppa PC, Vojdani A, Tagle C, et al. Multiplex PCR for the detection of
Mycoplasma fermentans, M. hominis, and M. penetrans in cell cultures and
blood samples of patients with chronic fatigue syndrome. Mol Cell Probes.
12:301-8, 1998.

7. Donta ST. Lyme Disease: A clinical challenge.  J Spirochet and Tick Dis
2:50-51, 1995.

8. Donta ST. Tetracycline therapy of chronic Lyme Disease. Clin Infect Dis
25: S52-56, 1997.

9. Donta ST: Reactivation of latent Lyme Disease.  X Annual LDF
International Conference on Lyme Borreliosis, National Institutes of Health,
April 1997.

10.. Donta ST. Treatment of chronic Lyme disease with macrolide antibiotics.
In: Program
and abstracts of the VIIIth International Conference on Lyme Borreliosis;
June 20-24, 1999; Munich, Germany. Abstract P193.

11. Donta ST: Reactivation of Lyme Disease following OspA vaccine. Int J
Antimicrob Agents 17:S116-7, 2001.

12. Donta ST: The existence of chronic Lyme Disease. Current Treatment
Options in Infectious Diseases 3:261-2, 2001.

13. Dressler F, Whalen JA, Reinhardt BN and Steere AC. Western blotting in
the serodiagnosis of Lyme disease. J Infect Dis 167:392-400, 1993.

14. Fallon B and Nields JA.  Lyme disease: a neuropsychiatric illness.  Am J
Psych 141:1571-83, 1994.

15. Feder HM Jr, Gerber M, and Krause PJ. Early Lyme disease: a flu-like
illness without erythema migrans. Pediatrics 91:456-9, 1993.

16.  Fister RD, Weymouth LA, McLaughlin JC, et al. Comparative evaluation of
three products for the detection of Borrelia burgdorferi antibody in human
serum.  J Clin Microbiol 37:2834-7, 1989.

17. Georgilis K, Peacocke M, and Klempner MS.  Fibroblasts protect the Lyme
Disease spirochete, Borrelia burgdorferi, from ceftriaxone in vitro.  J
Infect Dis166:440-4, 1992.

18. Gross DM, Forsthuber T, Tary-Lehman M, et al. Identification of LFA-1 as
a candidate autoantigen in treatment-resistant Lyme arthritis. Science
281:703-6, 1998.

19. Klempner MS, Hu LT, Evans J, et al. Two controlled trials of antibiotic
treatment in patients with persistent symptoms and a history of Lyme Disease
N Engl J Med. 345: 85-92, 2001.

20. Levin JM, Nelson JA, Segretti J, et al. In vitro susceptibilities of
Borrelia burgdorferi to 11 antimicrobial agents. Antimicrob Agents Chemother
37:1444-6, 1993.

21. Luft BJ, Dattwyler RJ, Johnson RC, et al. Azithromycin compared with
amoxicillin in the treatment of erythema migrans. A double blind,
randomized, controlled trial. Ann Int Med 124:785-91, 1996.

22. Maurin M, Benoliel AM, Bongrand P, and Raoult D.  Phagolysosomal
alkalinization and the bactericidal effect of antibiotics: the Coxiella
burnetii paradigm. J Infect Dis 166:1097-102, 1992.

23. Nicolson GL, and Nicolson NL. Chronic infections as a common etiology
for many patients with chronic fatigue syndrome, fibromyalgia, and Gulf War
Illness. Intern J Med 1:42-6, 1998.

24. Pachner AR, Delaney E, O'Neill T, and Major E.  Inoculation of nonhuman
primates with the N40 strain of Borrelia burgdorferi leads to a model of
Lyme neuroborreliosis faithful to the human disease. Neurology 45:165-72,
1995.

25. Preac-Mursic V, Wilske B, Schierz G, et al. In vitro and in vivo
susceptibility of Borrelia burgdorferi.  Eur J Clin Microbiol 6:424-6, 1987.

26. Roberts ED, Bohm RP Jr, Lowrie RC Jr, et al. Pathogenesis of Lyme
neuroborreliosis in the Rhesus monkey: the early disseminated and chronic
phases of disease in the peripheral nervous system. J Infect Dis 178:722-32,
1998.

27. Seltzer EG, Gerber MA, Carter ML, et al. Long-term outcomes of persons
with Lyme disease. JAMA 283:609-616, 2000.

28.  Shadick NA, Phillips CB, Logigian EL, et al.  The long-term clinical
outcomes of Lyme Disease.  Ann Intern Med 121:560-7, 1994.

29. Steere AC, Malawista SE, Hardin JA, et al. Erythema chronicum migrans
and Lyme arthritis: the enlarging clinical spectrum.  Ann Intern Med
86:685-98, 1977.

30. Steere AC. Lyme Disease. NEJM 345:115-25, 2001.

31. Straubinger RK. PCR-based quantification of Borrelia burgdorferi
organisms in canine tissues over a 500-day postinfection period. J Clin
Microbiology 38:2191-9, 2000.

32. Wormser G, Nadelman RB, Dattwyler RJ, et al. Practice guidelines for the
treatment of Lyme disease. Clin Infect Dis 31(S1):S1-S14, 2001.