is Lyme disease?
Lyme disease is a bacterial infection, caused by spirochetes
from the Borrelia burgdorferi group. The infection is transmitted to humans
via bites of infected ticks.
Where is Lyme disease
Lyme disease mostly occurs in temperate forest regions of
Europe, Asia and the Americas. June and July are the seasonal peak of host-seeking
activities of infective nymphal-stage ticks in northern hemisphere areas where
the diseaseis endemic.
How common is Lyme disease?
the United states, 20-25,000 cases are reported annually; in the ten states where
the disease is found most often, the rate is over 30 cases per 100,000 population.
is still an issue, partly as statistics include only people who present with a
classic erythema migrans rash - the hallmark symptom of Lyme disease.
is Lyme disease transmitted?
Ticks infected with Borrelia burgdorferi
transmit Lyme disease. The tick most commonly associated with the disease in the
Northeast US is the blacklegged tick, Ixodes scapularis, but other ticks have
been identified as transmiission vectors elsewhere.
The larval and nymphal
stages of the tick are less than 2 mm; adult ticks are slightly larger. Ticks
usually transmit the disease to during the nymphal stage. This may be because
nymphs are so small that they can pass unnoticed on a person's body for days,
rather than hours; this gives them ample time to feed and transmit the infection.
research suggests that 24 to 36 hours is needed for the infection to be transmitted).
Lyme disease be spread from person-to-person?
It is theoretically possible
that the disease could be transmitted via blood transfusion or other contact with
infected blood or urine: no such incidents have been recorded. There is no evidence
of transission by air, food or water, or from sexual contact or even directly
from animals. There is little evidence that insects transmit Lyme disease.
is most at risk from Lyme disease?
Ticks find their way to the tips of
grasses and shrubs, and transfer to animals or persons who brush against the vegetation;
so those who live, work or hunt in endemic areas are at risk.
are the symptoms of Lyme disease?
Lyme disease is an inflammatory disease
characterized by a skin rash, joint inflammation, and flu-like symptoms. Many
people presenting with Lyme disease are unaware of the tick bite; they are more
likely to develop symptoms, as the tick may have been feeding for a longer period.
characteristic red lesion usually appears at the site of the tick bite. This may
be over three inches in diameter, often with a clear area in the middle.
symptoms may include:
- Inflammation of the large joints
Additional symptoms occasionally seen:
- Unusual behavior
are the long term effects of Lyme disease?
Physical examination of people
with advanced Lyme disease may reveal joint, heart, or brain abnormalities.
is the mortality rate for Lyme disease?
is Lyme disease diagnosed?
Diagnosis is primarily on the basis of clinical
examination, but this is difficult in the early stages of the disease1. However,
as many clinicians rely on the initial local lesion, false negatives are
common in early disease. If advanced or disseminated disease is suspected,
laboratory confirmation is vital - and useful.
there a treatment for Lyme disease?
Early and / or localized disease is
effectively treated with oral antibiotics - doxycycline (for adults) or amoxycillin
are the first line choices.
Late diagnosed or disseminated disease will
require extended therapy (14-28 days), and symptoms may indicate parenteral therapy.
Ceftriaxone is the first line antibiotic by the parenteral route.
there a way to prevent infection?
Current advice to people moving in high
risk areas is to be "Tick Aware"; this includes learning about tick-borne
diseases, such as Lyme disease.
- Use insect repellants over clothing
and on exposed skin
- Wear long sleeved clothes, fasted at the cuff
trousers, not shorts, tucked into socks
- Wear shoes or boots - not sandals
self and companions every 2-3 hours
- Perform a thorough skin search at
the end of the day.
- Pay special attention to skin fold areas and scalp
outdoor clothing outdoors and check carefully.
- Ensure pets do not bring
ticks into the home.
- remove any ticks - but don't panic!
should be removed carefully without twisting, jerking or squeezing; do not use
chemicals or heat - this may cause the tick to regurgitate infected blood back
into the wound, increasing the disease risk. Sometimes the ticks head or mouthparts
may become separated, with parts remaining in the wound - this is unlikely to
increase the risk of Lyme disease, but may lead to local skin infection. Tick
extractors are easily and cheaply available, and should be carried by those who
visit high-risk areas frequently.
Is there a Lyme
Lymerix was developed as a vaccine to protect against
Lyme Disease. Lymerix (Lyme Disease Vaccine [Recombinant OspA]) received FDA approval
in 1998, but was the subject of many reports of severe arthritis and the contraction
of Lyme Disease itself. Federal health authorities investigated whether some people
who received the Lymerix vaccine later developed severe cases of arthritis or
Lyme disease as a result.
There were many law suits, including class action,
and not all the legal battles are over.
In 2002, the maker withdrew it from
the market, citing poor sales, despite Federal health officials finding no evidence
that the vaccine was dangerous. Centers for Disease Control and Prevention had
advised that only those at high risk should be vaccinated, largely because the
vaccine did not offer complete protection. research suggests it was 80 percent
effective after a full course of three injections.
The vaccine to prevent
the illness is no longer available.
Can Lyme disease
be controlled environmentally?
Ticks are endemic; there is no realistic
expectation of the risk of tick-borne diseases being eradicated.
there legal protection for workers and others?
Employers have a duty of
care, and should ensure their employees who ned to move in high risk areas have
appropriate education, warnings and skin protection. There is legal recourse for
employees who are not forwarned and prepared for entering high risk areas.
visitors to high-risk areas that are open to the public are entitled to warnings
of the risk.
See the section on vaccine for more
on legal issues.
What can be learned from history?
1975, Lyme Disease was classified as disease in following the diagnsis of almost
fifty cases of pediatric arthritis in Lyme, Connecticut. The disease was originally
called 'Lyme Arthritis', until more was known and understood.
But Lyme disease
was not new; Alfred Buchwald described a case of degenerative skin disorder now
known as acrodermatitis chronica atorphicans, in 1883.
In 1909, Arvid
Afzelius described an expanding ring-like lesion (erythema migrans), and in 1921,
he speculated on the origin of the disease as the Ixodes ccapularis tick and linked
the disease with joint problems.
Over the next fifty years, further symptoms
were linked with the disease, culminating with Allen C. Steere's investigation
of a group of rashes and swollen joints in Lyme, Connecticut in 1975. In the same
year, Scrimenti published details of successful treatment of the rash with penicillin.
all the history, however, Steere's team misdiagnosed Lyme Disease as "Lyme
Arthritis" (juvenile rheumatoid arthritis) in 1977.
Most doubt was
removed in 1982, with Dr. Willy Burgdorfer's identification of the etiological
agent of the disease, Borrelia burgdorferi.
and Further Information Sources
Aucott, J., at al (2009) Diagnostic
challenges of early Lyme disease: Lessons from a community case series BMC
Infectious Diseases 2009, 9:79 [PDF]
I regret I cannot assist with individual cases or essays and school projects,
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Article written by Andrew Heenan BA (Hons), RGN, RMN