results of a passive tick surveillance system in alberta
DESCRIPTION
Results of a Passive Tick Surveillance System in Alberta. Allison N Scott, Daniel Fitzgerald, Lisa Lachance, Kimberley Simmonds, and the Arthropod-Borne Diseases Committee (AABDC ) Government of Alberta 2014 Canadian Public Health Association Conference Toronto, Ontario May 29, 2014. - PowerPoint PPT PresentationTRANSCRIPT
Results of a Passive Tick Surveillance System in Alberta
Allison N Scott, Daniel Fitzgerald, Lisa Lachance, Kimberley Simmonds, and the
Arthropod-Borne Diseases Committee (AABDC)
Government of Alberta
2014 Canadian Public Health Association Conference
Toronto, Ontario
May 29, 2014
Collaborators
Agriculture and Rural Development, GOA
Rashed Cassis
Daniel Fitzgerald
Alberta Health, GOA
Dean Blue
Patti Kowalski
Lisa Lachance
Martin Lavoie
Kimberley Simmonds
Theresa St. Jean2
The Arthropod-Borne Diseases Committee
Alberta Health Services
Lance Honish
First Nations and Inuit Health Branch
And Many More!
Outline
• Ticks & Lyme Disease• Tick Surveillance Program in Alberta• Results• Discussion & Next Steps
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Ticks & Lyme Disease
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Lyme Disease
• Borrelia burgdorferi– Vector: Ixodes spp ticks
• Identified in 1976 in Lyme, Connecticut– Cluster of juvenile arthritis cases
• Multi-system inflammatory disease– Early symptoms: Rash, headache, fever, fatigue– Can affect heart, joints, brain– Small number of patients can have pain, fatigue, or
other symptoms chronically after treatment
• Best if treated early
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http://en.wikipedia.org/wiki/Borrelia_burgdorferi
http://www.cdc.gov/ticks/symptoms.html
Lyme Disease – Key Point
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• Can be difficult to diagnosis as the symptoms can be non-specific, especially if characteristic rash absent
• Knowing that the individual has been in an endemic area and exposed to ticks is important for diagnosis
http://www.cdc.gov/ticks/symptoms.html
Ixodes scapularis
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• Black-Legged Tick– Carrier of Borrelia burgdorferi
• Feeding– Insert mouthparts– Several days
• Drop off
Ixodes spp Ticks
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• Endemic in the United States• Establishing themselves in Eastern Canada• Climate change: warm, mixed forest/grassland
Ogden 2014 CCDR Volume 40-5
Adventitious Tick: Going where no Ixodes has gone before
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• One method of spread: migratory birds• Flyway over Edmonton• Key: Suitable habitat to overwinter/reproduce
birding.about.comodbirdingbasicsssNorth-America-Migration-Flyways.htm
Tick Surveillance Program
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Objectives:
1. Determine if Ixodes ticks can be found in Alberta
2. Determine the percentage of Ixodes ticks that carry Borrelia burgdorferi
3. Utilize geographic information to pick sites for active surveillance
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Passive Surveillance
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Companion Animals
Veterinarian
Humans and the Environment
AHS Environmental Health Office
Agriculture and Rural
Development Lab
Alberta Health
Methods
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• Standardized lab methods– Dichotomous identification key to speciate ticks– Established PCR protocol utilized to identify Borrelia
burgdorferi
• Descriptive statistics (SAS)• Mapped postal code of residence (ARC GIS)
• Restricted to hosts that were Alberta residents and had not travelled in the previous 2 weeks.
• Finding nymph or larva would suggest a population capable of reproducing
Results
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Results
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All Tick species
Ixodes species
B. burgdorferi positive
Ixodes spp Total Ticks Submitted 960 171 (18%) 27 (16%)
Ticks Submitted by Alberta Residents With No Travel Outside of Alberta
580 139 (24%) 25 (18%)
Tick Submitted by Alberta Residents With No Travel
378 105 (28%) 21 (20%)
• Only adult Ixodes ticks found from individuals who had not travelled
Results
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• 54% of Ixodes ticks submitted by Alberta residents with no travel history reside in Edmonton Zone
– Submitter’s Postal Code of Residence
– No travel in previous two weeks
Results
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• Submitter’s Postal Code of Residence• No travel in previous two weeks
Discussion & Next Steps
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Discussion
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• Ixodes ticks found in Alberta• Mostly in Edmonton Zone• 20% of Ixodes positive for Borrelia
burgdorferi
• Only adults found• But more than one tick likely acquired in
certain areas
Active Surveillance Triggered
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Criteria Reasonable Evidence Strong EvidenceSame Submitter *
1 or more nymph or larval blacklegged ticks
>1 blacklegged tick of any stage from the same person or animal in a suitable environment
Different Submitter*
>1 blacklegged tick of any stage from a different submitter in a suitable environment
>2 blacklegged tick submissions of any stage found at least 1 year apart
AND The ticks were found in a
suitable environmentHuman Cases
Single locally acquired human case
Cluster of locally acquired human cases
* In the same location. The location is in the same town, city or geographic area not defined by a specific surface area size.
Active Surveillance for Ticks
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• Drag sampling 5 sites weekly, May-June 2014• If Ixodes found: Heightened
Active Surveillance • Likely include small mammal
trapping
http://www.youtube.com/watch?v=QfKhopJNuj0
Strengths and Limitations
• Strengths:– Strong partnership between Alberta Agriculture, Alberta
Health Services, and Alberta Health– Collaborating with municipalities
• Limitations:– Residential postal codes, not locations– Unable to interview companion animal owners– Postal codes for companion animals currently only
available for 2013– Small sample size
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Next Steps
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• Active surveillance
• Changes to forms– Enhanced information on outdoor locations pets/people
had been in previous two weeks
• Continued passive surveillance– Increase sample sizes
• Enhanced advertising for 2014 season
Questions?
• www.health.alberta.ca/health-info/lyme-disease
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Ixodes spp – Life cycle
25CDC
Tick Surveillance
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• Surveillance: – “Systematic ongoing collection, collation, and analysis
of data and the timely dissemination of information to those who need to know so that action can be taken.”
• Passive Surveillance and Active Surveillance
Last, John M. 2001. A Dictionary of Epidemiology, 4th edition. Oxford University Press, Inc
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