Joint Committee on Health and Children
(Thursday 18th December 2014)
Presentation by Dr. Bartley Cryan, Consultant Medical Microbiologist,
Cork University Hospital
(Previous Appointment: Lecturer Medical Microbiology, Charring Cross Hospital
& Westminster Medical School London)
Publications of relevance.
Lyme disease in Ireland.
Cryan B, Cutler S, Wright DJ.
Ir Med J. 1992 Jun;85(2):65-7.
Lyme disease in paediatrics.
Cryan B, Wright DJ.
Arch Dis Child. 1991 Nov;66(11):1359-63.
1. Current Post.
1.1 I work as a consultant Medical Microbiologist in Cork University Hospital, one of
the busiest medical microbiology laboratories in the country. The Department is an
INAB accredited laboratory and is a Medical Microbiology Higher Specialist Training
Centre for the RCPI.
1.2The department receives almost 500,000 samples per year from the CUH group
hospitals and most of the GPs in the old Southern Health Board catchment area.
We examine approximately 180,000 serology/virology samples per year of which
1000 are examined for Lyme disease antibodies. We refer all samples with positive
Lyme Disease screening tests to the Rare and Imported Pathogens Laboratory (RIPL),
Public Health England Porton. We had 30 confirmed serological positives patients in
2013.
2. Introduction
2.1 “Lyme borreliosis(LB) is a tick-transmitted bacterial infection caused by some
members of the spirochete group Borrelia burgdorferi sensu lato. LB is currently the
most prevalent tick-transmitted infection in temperate areas of Europe, North
America and Asia.” ECDC
2.2 Lyme borreliosis results from the transmission of the implicated bacteria,
Borrelia burgdorferi by hard bodies, Ixodes ticks. The ticks need to be attached to the
patient for 18-24 hours for transmission to occur.
Lyme was identified as a disease in its own right in 1975 by Steere and colleagues
and the causative agent was discovered in 1981 by Willi Burgdorfer.
Between 10% and 20% of untreated cases will go on to develop nervous system
symptoms. Arthritis will develop in about half of untreated cases, while cardiac
complications will occur in fewer than 10% of subjects not receiving antibiotics.
Cases contracted in North America tend to be more severe in every sense than those
contracted in Europe.
2.3 Since January 2012, Lyme disease has been mandatorily notifiable in Ireland as
the entity ‘neuroborreliosis’
2.4 A vaccine for Lyme disease was introduced in 1998, but it has since been
withdrawn by the manufacturer due to controversies over alleged side effects.
3. Clinical Diagnosis of Lyme borreliosis
3.1 Traditionally, infections are provisionally diagnosed by eliciting clinical signs and
symptoms characteristic to the illness and the diagnosis is then confirmed by
detecting or growing the implicated microorganism from the infected tissue .
3.2 Unfortunately Borrelia burgdorferi, the causative organism of Lyme Disease is
very difficult to grow or detect by molecular or other methods. In such cases
evidence of infection is inferred by the presence of antibodies or activated cells.
Such serological methods have inherent problems,
 It takes time to develop a response
 There may be cross reactions/false positive results
 Presence of antibody implies previous exposure to the organism, it does not
necessarily confirm that the patients clinical symptoms are caused by B.
burgdorferi.
 Antibodies remain positive after treatment.
3.4 The earliest, clinical manifestation of Lyme borelliosis is the pathognomonic
erythema migrans, a circular erythematous rash spreading peripherally from the
central site of a tick bite.
This is seen in 70-80% of infections and develops between 3 and 32 days following a
tick bite. Serology can be negative in up to 30% of patients with erythema migrans,
later samples will be positive and confirm the diagnosis.
3.5 Other features of early Lyme Disease include, flu-like symptoms such as
headache, sore throat, neck stiffness, fever, muscle aches and general fatigue.
3.6 Occasionally, there may be more serious symptoms involving the nervous
system, joints, the heart or other tissues.
4. Diagnostic strategy
4.1 We follow the testing guidelines recommended by the US Centre for Disease
Control & Infectious Diseases Society of America and the UK Health Protection
Agency which recommend a two tire testing protocol. This system is also the one
currently most recommended by European authorities.
4.2 The first required test is the Enzyme Immunoassay (EIA) if this is negative an
alternative diagnosis should be considered. However bearing in mind that
the antibody response takes several weeks to reach a detectable level if the
patients symptoms are present for less than 30 days a repeat sample may be
considered.
4.3 For positive results a confirmatory western blot should be performed. We refer
all our positive EIA assays to the RIPL for confirmatory Western Blots, results are
usual available within 3 weeks.
4.4 While awaiting the Western Blot results the doctor looking after the patient is
contacted by the laboratory medical staff and the implications of the screening test
result are reviewed in the light of the patient’s clinical condition.
4.5 Once the confirmed positive result is available the case is again discussed with
the clinician and consideration may be given to the possibility of further tests such as
Lyme EIA of cerebrospinal fluid in cases of potential neurological Lyme disease or
joint fluid in the case of arthritis.
4.6 Of the 1000 samples examined for Lyme antibodies in 2013 only 30 were
confirmed positive. Samples are submitted throughout the year with a peak in late
summer.
4.7 While not formally recorded, patients predominantly receive their tick bites in
Ireland with some in the US or Europe.
4.8 While the collation of laboratory results with recognized Lyme Disease
syndromes can give rise to a confident diagnosis the usefulness of serology in
reactivation or post Lyme syndrome is less beneficial as such patients have pre
existing antibodies to B. burgdorferii and reliable tests for such conditions need to be
developed.
Bartley Cryan 16. Dec. 2014
MC Reg 003789