Identifying the last supper: utility of the DNA barcode library for bloodmeal identification in ticks

Authors

  • T. D. GARIEPY,

    1. Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON, Canada N5V 4T3
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  • R. LINDSAY,

    1. Public Health Agency of Canada, Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory, 1015 Arlington Street, Winnipeg, MB, Canada R3E 3R2
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  • N. OGDEN,

    1. Public Health Agency of Canada, Environmental Issues Division Centre for Food-borne, Environmental and Zoonotic Infectious Diseases C.P. 5000 Saint-Hyacinthe, Quebec, Canada J2S 7C6
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  • T. R. GREGORY

    1. Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, ON, Canada N1G 2W1
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T. D. Gariepy, Fax: 1-519-457-3997; E-mail: tara.gariepy@agr.gc.ca

Abstract

Ticks are among the most important vectors of disease in the Northern Hemisphere, and a better understanding of their feeding behaviour and life cycle is critical to the management and control of tick-borne zoonoses. DNA-based tools for the identification of residual bloodmeals in hematophagous arthropods have proven useful in the investigation of patterns of host use in nature. Using a blind test approach, we challenged the utility of the DNA barcode library for the identification of vertebrate bloodmeals in engorged, field-collected Ixodes scapularis. Universal vertebrate primers for the COI barcode region successfully amplified DNA from the host bloodmeal and only rarely amplified tick DNA. Of the 61 field-collected ticks, conclusive genus- and species-level identification was possible for 72% of the specimens. In all but two cases, barcode-based identification of the bloodmeal was consistent with the morphological identification of the vertebrate host the ticks were collected from. Possible explanations for mismatches or ambiguities are presented. This study validates the utility of the DNA barcode library as a valuable and reliable resource for the identification of unknown bloodmeals in arthropod vectors of disease. Future directions aimed at the refinement of these techniques to gain additional information and to improve the amplification success of digested vertebrate DNA in tick bloodmeals are discussed.

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