National Lyme Disease Meeting
March 8-9, 2006

PDF Version (288 KB, 59 pages)

Table of Contents

ACKNOWLEDGEMENTS
EXECUTIVE SUMMARY
INTRODUCTION TO REPORT
WELCOME AND OPENING REMARKS
PLENARY SESSION I: EPIZOOTIOLOGY

• Epizootiology of Lyme disease in the United States (Joseph Piesman)
• Lyme Borreliosis Risk Assessment: Animal Surveillance (Ian Barker)
• Surveillance for Ixodes scapularis in Canada (Robbin Lindsay)
• Geographic Distribution of Ixodes scapularis Tick and Borrelia burgdorferi in Canada: Past, Present and Future (Nicholas Ogden)
• Update on the Ecology of Lyme disease and Ixodes species on the West Coast (Muhammad Morshed)
• Lyme disease and Vector Ticks in Canada (Joan McComas for John Scott) Discussion and Questions and Answers related to Plenary Session I

PLENARY SESSION II: DIAGNOSIS AND LABORATORY TESTING

• Lyme Testing: The New and Old Revisited (Nick Harris)
• Laboratory Testing for Lyme Disease (Barbara Johnson)
• Lyme Disease Testing in Canada (Harvey Artsob)
• Discussion and Questions and Answers related to Plenary Session II

PLENARY SESSION III:

• Clinical Aspects of Lyme disease (Raymond Dattwyler)
• Issues in the Diagnosis of Lyme Disease (Sam Donta)

PLENARY SESSION IV: HUMAN EPIDEMIOLGY AND SURVEILLANCE

• Surveillance for Lyme Disease in the United States (Paul Mead)
• Lyme disease in Canada 1994-2004 (Peter Buck)
• Lyme disease in Ontario 1989-2002 (Linda Vrbova)
• Surveillance in British Columbia (Bonnie Henry)
• Human Surveillance of Lyme Disease in Manitoba (Greg Hammond)
• Prevalence as a Measure of Burden of Disease in the Population (Daniel Cameron)

PLENARY SESSION V: INFORMATION AND COMMUNICATION

• Communicating Public Health: A Strategic Risk Communication Approach (Élaine Chatigny)
• Ethical Issues in Health Communication (Lorraine Johnson)
• Opportunities for Research Partnerships (Judith Bray)
• Discussion and Questions and Answers related to Plenary Session V

BREAKOUT SESSION REPORTS
BREAKOUT SESSION 1

• Epizootiology Group
  • Current Issue/Question 1.1: Review the Criteria for defining the status of Ixodes dammini (Id) in an area
  • Issue/Question 1.2: Epizootiology consensus statement
  • Issue/Question 1.3: Methods of detecting B. burgdorferi in tick vectors and wildlife reservoirs
  • Issue/Question 1.4: General recommendations regarding epizootiologic surveillance
• Clinical Diagnosis Group
  • Issue/Question 2.1: Review the definitions of erythema migrans (EM) and the late manifestations of LD
  • Issue/Question 2.2: Clinical manifestations suggestive of LD
  • Issue/Question 2.3: Disseminated Disease
  • Issue/Question 2.4: Indications for specific serologic testing for LD
  • Issue/Question 2.5: Interpretation of positive Lyme serology in patients
• Laboratory Diagnosis Group
  • Issue/Question 3.1: Laboratory evidence of B. burgdorferi infection
  • Issue/Question 3.2: Recommendations for Standardization and Use of Laboratory Tests for Diagnosis of LD
  • Issue/Question 3.3: Identify other or new approaches to laboratory diagnosis of LD
  • Issue/Question 3.4: Interpretation of positive Lyme serology in patients

BREAKOUT SESSION II

• Epidemiology and Surveillance Group
  • Issue/Question 4.1: What approaches to surveillance (e.g., active surveillance methods) should be taken to improve monitoring of the spread of, or presence of, tick populations in the light of the potential role of birds in transporting ticks, changes in animals/vector ranges, and climate change?
  • Issue/Question 4.2: Investigation of B. burgdorferi sub-species
• Clinical and Surveillance Group
  • Issue/Question 5.1: Probable case definition
  • Issue/Question 5.2: Should serologic testing be applied only to individuals who have travelled to known endemic area and/or have signs and symptoms compatible with LD?
  • Issue/Question 5.3: Should there be separate case definitions for clinical diagnosis and surveillance purposes?
• Human Surveillance Group
  • Issue/Question 6.1: Data on human cases of LD
  • Issue/Question 6.2: The human case definition
  • Issue/Question 6.3: Is there value in obtaining baseline data on human serology in different locations in Canada?
  • Issue/Question 6.4: How should the sensitivity and specificity of current and novel laboratory diagnostic techniques be quantified for use in Canada for surveillance studies and clinical diagnosis.

PLENARY SESSION VII: NEXT STEPS
NEXT STEPS
WRAP-UP
APPENDICES

• Glossary of Terms
• National Lyme Disease Meeting – Agenda
• National Lyme Disease Meeting – List of Participants
• National Lyme Disease Meeting – Facilitation & Administrative Support

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Meeting Planning Committee

Public Health Agency of Canada
Paul Sockett
Peter Buck
Nicholas Ogden
Robbin Lindsay
Harvey Artsob
Adelaida Bustamante

Canadian Lyme Disease Foundation
Joan McComas

British Columbia Centre for Disease Control
Bonnie Henry
Muhammad Morshed

University of Iowa and Connecticut
Sam Donta

Manitoba Health
Greg Hammond

Nova Scotia Department of Health
Richard Gould

Review Committee

Public Health Agency of Canada
Paul Sockett
Peter Buck
Nicholas Ogden
Robbin Lindsay
Harvey Artsob
Tanya Vervloet

Canadian Lyme Disease Foundation
Joan McComas

British Columbia Centre for Disease Control
Bonnie Henry
Sam Donta

Manitoba Health
Greg Hammond

Nova Scotia Department of Health
Richard Gould

Acknowledgements

The Public Health Agency of Canada is grateful to all contributors to the meeting on Lyme disease who provided perspectives representing the findings and concerns of national and international experts, public health professionals, the Canadian Lyme Disease Foundation and the National ME/FM Action Network. The Agency also wishes to express its gratitude to the Planning Committee for their support in organizing the meeting and in the development of the agenda, and to the Canadian Lyme Disease Foundation for identifying a speaker for each session. We would also like to thank all these partners, including the Review Committee, for their continued support in completing this report. Finally, we wish to acknowledge the administrative staff who worked diligently to ensure the success of the meeting and the completion of this report, and facilitation team for their valuable help in keeping discussion focused.

Executive Summary

In Canada, diseases transmissible between animals and humans, or zoonotic diseases, represent an increasingly important public health threat and are caused by a wide-range of pathogens including bacterial, viral, fungal, rickettsial, chlamydial, prion and parasitic agents. Zoonotic diseases infect farmed, companion and wild animals as well as humans, and include many agents that are recognized as emerging threats. Lyme disease is a tick transmitted zoonotic disease of bacterial etiology which is currently of growing concern in Canada.

There are many factors, including environmental and climatic changes, changes in human behaviour and travel, urbanization, ecological changes and others, that affect the level of risk associated with zoonotic and vector-borne diseases such as Lyme disease. The documentation of newly identified populations of blacklegged ticks infected with Borrelia burgdorferi, the bacteria which causes Lyme disease, in some areas of Manitoba, Ontario and Nova Scotia indicates the need for a broader, systematic approach to tick and human case surveillance, in order to better assess the risk of human infection. Improved understanding of risk would be a driver to developing new approaches in the control, prevention and investigation of Lyme disease in Canada.

On March 8-9^th, 2006, the Public Health Agency of Canada sponsored a meeting of national and international scientific experts on Lyme disease, communication experts, provincial representatives, representatives from the Canadian Lyme Disease Foundation and the National ME/FM Action Network. The intent of the meeting was to begin a process to review and update the guidelines from the 1991 consensus conference on Lyme disease. To facilitate this process the meeting reviewed current knowledge on the epidemiology and diagnosis of Lyme disease, and took the opportunity to identify and prioritise research requirements. Consideration was also given to new approaches to surveillance and risk communication of Lyme disease in Canada. The discussion groups, plenary presentations and question and answer periods provided an opportunity to review current guidelines on the epidemiology, diagnosis and treatment of Lyme disease which are based on recommendations from the January 15-16, 1991 Consensus Conference on Lyme disease.

The two-day meeting included presentations which addressed epidemiological, ecological, diagnostic, public health, communications and ethics perspectives and identified significant research findings and issues relating to Lyme disease in Canada and the United States. The plenary sessions provided updates and current information on the epizootiology, diagnosis and laboratory testing, human epidemiology and surveillance, and information and communication of Lyme disease issues.

The tick vector of B. burgdorferi in eastern and central Canada, Ixodes scapularis, has steadily expanded its range in the United States over the last 30 years, and similar range expansions have been observed in parts of southern Manitoba, eastern Ontario, and Nova Scotia in recent years. The need for systematic sampling for ticks together with ecological risk modelling was identified as key to developing predictive risk maps.

The role of migrating passerine birds in transporting vector ticks (I. pacificus and I. scapularis) was demonstrated to be one important mechanism for range expansion, and could help to explain the occurrence of human Lyme disease cases in parts of Canada where the vector ticks are not known to be established. The major bird migration routes transect Lyme disease endemic areas of the United States and Canada. Spring migrating birds stop-over to feed at times that coincide with the seasonal activity of immature stages of I. pacificus and I. scapularis. This has potential to impact the future range of ticks as well as areas of risk of human infection in Canada.

Ongoing expansion of Lyme disease in Canada, however, will be dependent on numerous factors including climate, available habitat, and distribution of potential host species. Current modelling suggests that increased ambient temperatures with climate change could result in expansion of tick range to encompass most of the heavily populated regions of southeastern Canada.

Currently, Lyme disease testing in Canadian Laboratories is based on a two-tiered approach, utilizing an ELISA as a front-line test. Reactors are further examined using IgG and, or IgM western blot tests. This approach is the same as that adopted by the US CDC as the most likely to give the best combination of sensitivity and specificity. However, it was clear in discussions that there were concerns that current testing procedures could miss some patients with Lyme disease. It was acknowledged by all that issues such as the testing approach, stage of disease, the time between tick bite and test, persistence of antibody responses, interpretation of western blot tests, impact of early treatment, and the technical demands of the western blot test can affect test outcomes and that newer and developing test procedures should be evaluated.

While early stage Lyme disease may be characterized by erythma migrans (EM), which is sufficiently distinctive to permit clinical diagnosis by an experienced clinician, acute disseminated disease is characterized by a number of systemic presentations affecting multiple organ systems. Late infection appears to be more specifically associated with neurologic disease and arthritis.

Concern was expressed about suggested links between Lyme disease and Multiple Sclerosis, Chronic Fatigue Syndrome and Fibromyalgia, and the existence of post Lyme disease syndrome, described by some as chronic Lyme disease. Differences were apparent in attendees concerning the existence and definition of what is described as chronic Lyme disease. Part of the problem is the variety of non-specific symptoms associated with the latter, and it was suggested that while it is difficult to relate these symptoms to Lyme disease, the possibility should be further explored.

The number of reported cases of Lyme disease in Canada is relatively low (20-60 new cases reported annually), with over half associated with travel outside of the country. The actual number of cases is undoubtedly higher given that not all clinical cases are captured by current surveillance approaches and there are indications that the incidence of the disease may be increasing. The recent inclusion of Lyme disease as a nationally notifiable disease may help address these issues over time. The use of definitions specifically for surveillance may also help improve ascertainment of case numbers in Canada.

The breakout sessions, which covered the areas of epizootiology, laboratory diagnosis, and human surveillance, provided an opportunity for more in-depth discussions which, in turn, provided recommendations for the revision of the 1991 guidelines and the 1999 national notifiable disease case definition for Lyme disease. Specific comments and recommendations are outlined in the report and will be used as a starting point for revision of the 1991 guidelines.

Discussions in the breakout groups reached consensus on a series of recommendations related to the epizootiology of vector ticks, the definitions (criteria) of tick status in a geographic area, and current distribution of vector ticks in Canada, including the potential role of bird-borne ticks in the future range expansion of tick populations. Consensus was not reached on a number of issues or statements related to the clinical and laboratory diagnosis of Lyme disease due either to disagreement between discussants or because some of the issues identified for discussion were not covered due to lack of time. Some areas of concern could be addressed through clear communication and understanding of the different objectives of a surveillance case definition versus a clinical case definition, as well as improved description of clinical presentations of Lyme disease. There was consensus in plenary session about the need to establish technical working groups to specifically address the more complex and contentious issues by thorough appraisal of available scientific literature.

Positive steps were taken to recommend changes to the wording of the existing (1991) guidelines to update statements related to evidence of infection, and the use of specific diagnostic tests. In particular, it was re-emphasised that lack of evidence of a visit to an area where Lyme disease is established should not influence a clinical consideration of Lyme disease diagnosis in individual patients. Recommendations from the conference should be fully considered in future revisions of a case definition relevant to EM in an individual in a risk area and EM in an individual not in a risk area.

The final plenary session was a discussion on the compiled research needs identified throughout the two days of deliberations and included recommendations covering three key areas: the organism, B. burgdorferi, which causes Lyme disease; the disease itself; and the epidemiology of vector ticks. The genetic diversity and pathogenesis of B. burgdorferi were identified as current priorities for research. Focus on the disease itself should include improvement in diagnostic technologies and approaches, improvement in understanding the clinical presentations and the burden of disease; and improvement in physician awareness of, and knowledge about, Lyme disease.

There was also consensus among participants on critical key issues and recommended next steps which included the following:

• Establish a group that could craft a set of case definitions, taking into account the need for two sets of definitions, one for surveillance and one for clinical diagnostic purposes.
• Examine the possibility of engaging CIHR in addressing Lyme disease research priorities. This will help in framing more specific questions on research topics identified in this report.
• Identify a mechanism for regular review of the Lyme disease situation and national guidelines.
• Examine approaches for enhancing communications to the public, physicians and public health professionals on Lyme disease risks, prevention and related issues.
• Identify and explore new sources of funding, for example, risk identification and prevention for the 2010 Olympic Games.

Lyme disease poses unique challenges in a changing environment in which further expansion of tick-infested areas and increased risk of human infection are likely to occur. In light of these challenges, the Public Health Agency of Canada will continue to work collaboratively to monitor these risks, enhance diagnostic approaches and provide public health advice, including revision of the 1991 guidelines, based on the best available scientific evidence. Until new guidelines have been approved through the Public Health Network Council, the information in this report may be useful to public health officers and healthcare professionals for consideration in diagnosing, confirming, and reporting cases of Lyme disease in Canada.

Introduction to the Report

The Public Health Agency of Canada brought together scientific experts, external stakeholders and other affected jurisdictions to present their own or their organizational perspectives on areas that need to be considered in the control, prevention, and management of Lyme disease in Canada. The report is a compilation of these perspectives and recommendations and unless otherwise stated does not necessarily represent a consensus of all participants.

This report has been divided into two main sections. The first consolidates all plenary presentations and includes the text of the brief Questions and Answers which followed each plenary session. Section two represents the summaries of the breakout groups, each of which presented comments based on specific tasks or questions and included recommendations and discussions on next steps or revisions to the text of the existing guidelines. The report concludes with a brief presentation of next steps and a summary of the proceedings.

The planning committee for the meeting recognized that addressing Lyme disease epidemiology and diagnosis would raise many issues which would challenge the existing guidelines as well as the views of experts and advocacy groups. To help the decision-making process, the committee requested the facilitator to present a decision-making framework to be agreed at the commencement of the meeting. The framework agreed upon at the meeting was based on definitions of different levels of decisions and is outlined below:

• Consensus Decision meant no one has a major objection; everyone can live with it
• Majority Decision means at least 2/3 of participants agree and minority concerns are identified
• Unresolved Issue means there is no consensus or majority decision
• Decisions may include proposals for processes (eg. Expert group) and/or data or research gaps.