|Title||Epidemiology of ticks submitted from human hosts in Alberta, Canada (2000-2019)|
|Publication Type||Journal Article|
|Year of Publication||2022|
|Journal||Emerg Microbes Infect|
|Authors||Kanji JN, Isaac A, Gregson D, Mierzejewski M, Shpeley D, Tomlin P, Groechel M, Lindsay LR, Lachance L, Kowalewska-Grochowska K|
|Keywords||alberta, borrelia burgdorferi, dermacentor, ixodes, lyme, tick|
The geographic range and occurrence of tick species is dynamic. This has important public health implications due to important tick species that can transmit pathogens. This study presents a retrospective review of tick genera recovered from humans and submitted for identification in Alberta, Canada over a 19-year period. The total number of ticks and proportion of genera were analyzed over time. Molecular testing for a number of pathogens associated with Ixodes scapularis and I. pacificus was conducted. A total of 2,358 ticks were submitted between 2000-2019, with 98.6% being acquired in Alberta. The number of ticks submitted increased significantly over time (p<0.0001). Dermacentor ticks were the most abundant genus, followed by Ixodes and Amblyomma. There was a significant decrease in the proportion of Dermacentor ticks between 2013-2019 (p=0.02) with a corresponding increase in proportion of Ixodes ticks over the same time (p=0.04). No statistically significant change in seasonality was identified. Borrelia burgdorferi was detected in 8/76 (10.5%; 95% CI 5.4-19.4%) of all I. scapularis and I. pacificus ticks submitted. This translated to a B. burgdorferi positivity of 0.35% (95% CI 0.15-0.68%) among all ticks received. Dermacentor species (especially D. andersoni) remains the most common tick feeding on humans in Alberta. Small numbers of vector species (including I. scapularis/pacificus) are encountered annually over widely separated geographic areas in the province. The risk of exposure to tick-borne pathogens (e.g. Lyme disease) in Alberta remains low.