Impact of Unexplored Data Sources on the Historical Distribution of Three Vector Tick Species in Illinois

Abstract

We updated the Illinois historical (1905–December 2017) distribution and status (not reported, reported or established) maps for Amblyomma americanum (L.) (Acari: Ixodidae), Dermacentor variabilis (Say) (Acari: Ixodidae), and Ixodes scapularis (Say) (Acari: Ixodidae) by compiling publicly available, previously unexplored or newly identified published and unpublished data (untapped data). Primary data sources offered specific tick-level information, followed by secondary and tertiary data sources. For A. americanum, D. variabilis, and I. scapularis, primary data contributed to 90% (4,045/4,482), 80% (2,124/2,640), and 32% (3,490/10,898) tick records vs 10%, 20%, and 68%, respectively from secondary data; primary data updated status in 95% (62/65), 94% (51/54) and in 90% (9/10) of the updated counties for each of these tick species; by 1985 there were tick records in 6%, 68%, and 0% of the counties, compared to 20%, 72%, and 58% by 2004, and 77%, 96%, and 75% of the counties by 2017, respectively for A. americanum, D. variabilis, and I. scapularis. We document the loss of tick records due to unidentified, not cataloged tick collections, unidentified ticks in tick collections, unpublished data or manuscripts without specific county location, and tick-level information, to determine distribution and status. In light of the increase in tick-borne illnesses, updates in historical distributions and status maps help researchers and health officials to identify risk areas for a tick encounter and suggest targeted areas for public outreach and surveillance efforts for ticks and tick-borne diseases. There is a need for a systematic, national vector surveillance program to support research and public health responses to tick expansions and tick-borne diseases.

Landscape features predict the current and forecast the future geographic spread of Lyme disease

“…We took advantage of data made possible by the designation of Lyme disease as a nationally reportable illness after 1991 and extensive surveillance efforts by many researchers to characterize the distribution of I. scapularis. However, there could be important sources of bias in using these data, including variation in surveillance efforts, imperfect reporting of tick occurrence and human cases [62], assumptions we made to glean data from literature, limitations in using the first discovery of either I. scapularis or Lyme disease, and the spatialtemporal grain used in the analyses. Lyme disease cases are reported in the county of residence rather than the location of before first tick report Lyme disease incidence per 100 000 after first tick report 1 9 6 7 -1 9 7 1 1 9 7 2 -1 9 7 6 1 9 7 7 -1 9 8 1 1 9 8 2 -1 9 8 6 1 9 8 7 -1 9 9 1 1 9 9 2 -1 9 9 6 1 9 9 7 -2 0 0 1 2 0 0 2 -2 0 0 6 2 0 0 7 -2 0 1 1 2 0 1 2 -2 0 1 6 (a) (b) royalsocietypublishing.org/journal/rspb Proc.…”

Comparing Contributions of Passive and Active Tick Collection Methods to Determine Establishment of Ticks of Public Health Concern Within Illinois

“… County distribution status changes for A. americanum and A. maculatum due to 2018 year of I-TICK. *Historic status data for A. maculatum comes from Bishopp and Trembley (1945) , Gilliam et al (2020) , and Phillips et al (2020) . …”

“…Historic tick data have shown the distributions of the dominant tick vectors within Illinois vary by species ( Gilliam et al 2020 ). Dermacentor variabilis is the most widespread species within the state, but its known distribution is incomplete.…”

“…Increased incidence of TBDs in Illinois is related to expanding geographical ranges of hard-bodied (Ixodida: Ixodidae) vector ticks ( Eisen and Eisen 2018 , Gilliam et al 2020 , Lehane et al 2020 ). Currently, Illinois is on the frontlines of geographic expansion for multiple tick species ( Rydzewski et al 2011 , Springer et al 2014 , Lockwood et al 2018 , Phillips et al 2020 , Tuten et al 2020 ).…”

“…Recent research conducted in Illinois used historical data from 1905 to 2017 to determine the geographic distribution of D. variabilis , A. americanum , and I. scapularis ( Gilliam et al 2020 ). The county status was categorized using the same county-scale criteria as Dennis et al, in which at least six ticks of any given life stage or at least two life stages must be identified within 12 mo to declare a county ‘established’ for a particular species ( Dennis et al 1998 ).…”