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Questions
and Answers About Lyme Disease
Q. How do people
get Lyme disease?
A. By the bite of a tick infected with Lyme disease bacteria. (Click
here for an image of a deer tick.)
Q. What is the
basic transmission cycle?
A. Immature ticks become infected by feeding on small rodents, such
as the white-footed mouse, and other mammals that are infected with the
bacterium Borrelia
burgdorferi.
In later stages, these ticks then transmit the Lyme disease bacterium
to humans and other mammals during the feeding process. Lyme disease bacteria
are maintained in the blood systems and tissues of small rodents.
Q. Could you
get Lyme disease from another person?
A. No, Lyme disease bacteria are NOT transmitted from person-to-person.
For example, you cannot get infected from touching or kissing a person
who has Lyme disease, or from a health care worker who has treated someone
with the disease, or by sexual contact.
Q. What are the
signs and symptoms of Lyme disease?
A. Within days to weeks following a tick bite, 80% of patients will
have a red, slowly expanding "bull's-eye"
rash (called
erythema migrans), accompanied by general tiredness, fever, headache,
stiff neck, muscle aches, and joint pain. If untreated, weeks to months
later some patients may develop arthritis, including intermittent episodes
of swelling and pain in the large joints; neurologic abnormalities, such
as aseptic meningitis, facial palsy, motor and sensory nerve inflammation
(radiculoneuritis) and inflammation of the brain (encephalitis); and,
rarely, cardiac problems, such as atrioventricular block, acute inflammation
of the tissues surrounding the heart (myopericarditis) or enlarged heart
(cardiomegaly).
Q. What is the
incubation period for Lyme disease?
A. For the red "bull's-eye" rash (erythema migrans), usually
7 to 14 days following tick exposure. Some patients present with later
manifestations without having had early signs of disease.
Q.
Can a person be reinfected with Lyme disease?
A. Yes. Having had Lyme disease doesn't protect against reinfection.
Some persons have had Lyme disease more than once after re-exposure to
infective tick bites. This stresses the need for continued tick bite prevention
activities such as wearing appropriate clothing when in tick-infested
areas, daily tick checks, and quick removal of attached ticks.
Q. How many cases
of Lyme disease occur in the U.S.?
A. Lyme disease is the leading cause of vector-borne infectious illness
in the U.S. with about 23,000 cases reported in 2002, though the disease
is greatly under reported. Twelve states account for over 90% of reported
cases. More information can be found in the MMWR articles from August
8, 2003 / 53(31):741-750 and January
18, 2002 / 51(02);29-31.
Q.
How is Lyme disease treated?
A. According to treatment experts, antibiotic treatment for 3-4 weeks
with doxycycline or amoxicillin is generally effective in early disease.
Cefuroxime axetil or erythromycin can be used for persons allergic to
penicillin or who cannot take tetracyclines. Later disease, particularly
with objective neurologic manifestations, may require treatment with intravenous
ceftriaxone or penicillin for 4 weeks or more, depending on disease severity.
In later disease, treatment failures may occur and retreatment may be
necessary. (The Medical Letter, Vol. 42 (Issue 1077), May 1, 2000)
Q. Is the disease
seasonal in its occurrence?
A. Yes, Lyme disease is most common during the late spring and summer
months in the U.S. (May through August) when nymphal ticks are most active
and human populations are frequently outdoors and most exposed.
Q. Where is Lyme
disease most common?
A. Click on the map at right that shows reported cases of Lyme disease
in 2000 by patient's county of residence. Generally, Lyme disease is endemic
in the northeastern and upper midwest states. (See "Lyme
Disease—United States, 2000." MMWR. January 18, 2002;51:29-31.)
Q.Who is at risk for getting Lyme disease?
A. Persons in endemic areas who frequent sites where infected ticks
are common, such as grassy or wooded locations favored by white-tailed
deer in the northeastern and upper midwest states, and along the northern
Pacific coast of California.
Q. Is there a
vaccine avialable against Lyme disease?
A. No. As of February 25, 2002 the manufacturer of the LYMErix™
Lyme disease vaccine announced that it would no longer be commercially
available.
Q. Does
the Lyme disease vaccine which was previously available cause arthritis?
Are individuals with certain HLA-DR4 genetic subtypes more susceptible
to getting arthritis from that vaccine?
A. An association between naturally acquired treatment-resistant Lyme
disease arthritis, certain HLA-DR4 genetic subtypes, and high levels of
antibody to OspA of naturally acquired Borrelia burgdorferi has
been described in the medical literature (1, 2,
3). Because of the relationship between OspA antibodies
and treatment-resistant arthritis from naturally acquired infection, CDC’s
Advisory Committee on Immunization Practices (ACIP) had stated that the
vaccine should not be given to persons with treatment-resistant Lyme arthritis
(4). However, at this writing there is no scientific
evidence that the currently licensed (no longer avialable) Lyme disease
vaccine increases the recipient’s risk of arthritis. To the contrary,
there is good evidence that the risk of arthritis in vaccine recipients
is not significantly different from the risk in individuals who have received
placebo without OspA (5). ACIP has not recommended screening
of HLA type prior to vaccination. In the absence of evidence that the
vaccine causes arthritis, screening for HLA-DR4 subtypes before vaccination
would not seem to be a beneficial use of health resources.
- Kalish
RA, Leong JM, Steere AC. Association of treatment-resistant chronic
Lyme arthritis with HLA-DR4 and antibody reactivity to OspA and OspB
of Borrelia burgdorferi. Infect Immun 1993;61:2774-2779.
- Akin
E, McHugh GL, Flavell RA, et al. The immunoglobulin (IgG) antibody response
to OspA and OspB correlates with severe and prolonged Lyme arthritis
and the IgG response to p35 correlates with mild and brief arthritis.
Infect Immun 1999;173-181.
- Gross
DM, Forsthuber T, Tary-Lehmann M, et al. Identification of LFA-1 as
a candidate autoantigen in treatment-resistant Lyme arthritis. Science
1998;281:703-706.
- Centers
for Disease Control and Prevention. Recommendations
for the Use of Lyme Disease Vaccine - Recommendations of the Advisory
Committee on Immunization Practices. MMWR 1999;48:1-17.
(Also
available in PDF format
[742 KB, 39 pages].)
- Steere
AC, Sikand VK, Meurice F, et al. Vaccination against Lyme disease with
recombinant Borrelia burgdorferi outer-surface lipoprotein A
with adjuvant. N Engl J Med 1998;339:209-216.
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