Human-Biting Ixodes scapularis Submissions to a Crowd-Funded Tick Testing Program Correlate with the Incidence of Rare Tick-Borne Disease: A Seven-Year Retrospective Study of Anaplasmosis and Babesiosis in Massachusetts

Eric L Siegel; Nathalie Lavoie; Guang Xu; Catherine M Brown; Michel Ledizet; Stephen M Rich

doi:10.3390/microorganisms11061418

Human-Biting Ixodes scapularis Submissions to a Crowd-Funded Tick Testing Program Correlate with the Incidence of Rare Tick-Borne Disease: A Seven-Year Retrospective Study of Anaplasmosis and Babesiosis in Massachusetts

Microorganisms. 2023 May 27;11(6):1418. doi: 10.3390/microorganisms11061418.

Authors

Eric L Siegel¹, Nathalie Lavoie², Guang Xu¹, Catherine M Brown³, Michel Ledizet⁴, Stephen M Rich¹

Affiliations

¹ Laboratory of Medical Zoology, Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA.
² Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA.
³ Massachusetts Department of Public Health, Boston, MA 02108, USA.
⁴ L2 Diagnostics, LLC, New Haven, CT 06511, USA.

Abstract

Tick-borne zoonoses pose a serious burden to global public health. To understand the distribution and determinants of these diseases, the many entangled environment-vector-host interactions which influence risk must be considered. Previous studies have evaluated how passive tick testing surveillance measures connect with the incidence of human Lyme disease. The present study sought to extend this to babesiosis and anaplasmosis, two rare tick-borne diseases. Human cases reported to the Massachusetts Department of Health and submissions to TickReport tick testing services between 2015 and 2021 were retrospectively analyzed. Moderate-to-strong town-level correlations using Spearman's Rho (ρ) were established between Ixodes scapularis submissions (total, infected, adult, and nymphal) and human disease. Aggregated ρ values ranged from 0.708 to 0.830 for anaplasmosis and 0.552 to 0.684 for babesiosis. Point observations maintained similar patterns but were slightly weaker, with mild year-to-year variation. The seasonality of tick submissions and demographics of bite victims also correlated well with reported disease. Future studies should assess how this information may best complement human disease reporting and entomological surveys as proxies for Lyme disease incidence in intervention studies, and how it may be used to better understand the dynamics of human-tick encounters.

Keywords: anaplasmosis; babesiosis; passive surveillance; tick-borne diseases.

Grants and funding

The authors received no specific funding for this work. This study was supported by the crowd-funded resources of TickReport.com. Until 2020, TickReport.com was offered as a service of the University of Massachusetts, Amherst. In 2021, the University of Massachusetts, ceased to offer TickReport services and licensed Medzu, Inc. to be the sole provider of TickReport service.