Volume 30, Number 10—October 2024
Research
Rapid Increase in Seroprevalence of Borrelia burgdorferi Antibodies among Dogs, Northwestern North Carolina, USA, 2017–20211
, Katherine Tyrlik-Olk, Hilary Sandborn, Dana A. Giandomenico, Alexis M. Barbarin, Carl Williams, Paul L. Delamater, Barbara Qurollo, Stephanie van der Westhuizen, and Ross M. Boyce
Table 1
Borrelia burgdorferi seroprevalence and incident seropositivity among dogs screened for heartworm and tickborne diseases in Watauga County, North Carolina, USA, 2017–2021*
| Year | No. tests | Seroprevalence, no. (%) | Seroprevalence difference, % (95% CI)† | Incident seropositivity, no. (%) | Risk difference, % (95% CI)† |
|---|---|---|---|---|---|
| 2017 | 2,130 | 47 (2.2) | Referent | 45 (2.1) | Referent |
| 2018 | 2,114 | 77 (3.6) | 1.54 (0.65–2.44) | 60 (2.8) | 0.71 (−0.23 to 1.65) |
| 2019 | 2,447 | 163 (6.7) | 4.83 (3.73–5.93) | 145 (5.9) | 3.74 (2.62–4.87) |
| 2020 | 2,617 | 288 (11.0) | 9.04 (7.76–10.31) | 209 (8.0) | 5.82 (4.61–7.03) |
| 2021 | 3,033 | 339 (11.2) | 9.39 (8.12–10.66) | 231 (7.6) | 5.49 (4.36–6.62) |
*Dogs were screened by using the IDEXX SNAP 4DX Plus assay (IDEXX Laboratories, Inc., https://www.idexx.com). Seroprevalence was defined as the proportion of results positive for Borrelia burgdorferi antibodies among all IDEXX SNAP 4DX Plus tests completed for each year of the study. Incident seropositivity was defined as the dog’s first Borrelia burgdorferi–positive result during the study period. †Absolute measures of effect were analyzed by using generalized estimating equations with robust variance estimators to account to correlations that arise from repeated measures. Models assume an exchangeable correlation structure.
1Preliminary results from this study were presented at the Virginia Mosquito Control Association Annual Conference; February 14–15, 2023; Virginia Beach, Virginia, USA; and the North Carolina Mosquito and Vector Control Association Annual Meeting; November 15–17, 2023; Carolina Beach, North Carolina, USA.