Citizen science informs human-tick exposure in the Northeastern United States

Abstract

Background Tick-borne disease is the result of spillover of pathogens into the human population. Traditionally, literature has focused on characterization of tick-borne disease pathogens and ticks in their sylvatic cycles. A limited amount of research has focused on human-tick exposure in this system, especially in the Northeastern United States. Human-tick interactions are crucial to consider when assessing the risk of tick-borne disease since a tick bite is required for spillover to occur. Methods Citizen scientists collected ticks from the Northeastern US through a free nationwide program. Submitted ticks were identified to species, stage, and sex. Blacklegged ticks, Ixodes scapularis , were tested for the presence of Borrelia burgdorferi sensu lato (s.l.) and hard-tick relapsing fever Borrelia . Seasonality of exposure and the citizen science activity during tick exposure was recorded by the citizen scientist. A negative binomial model was fit to predict county level CDC Lyme disease cases in 2016 using citizen science Ixodes scapularis submissions, state, and county population as predictor variables. Results A total of 3740 submissions, comprising 4261 ticks, were submitted from the Northeastern US and were reported to be parasitizing humans. Of the three species submitted, blacklegged ticks were the most prevalent followed by American dog ticks and lone star ticks. Submissions peaked in May with the majority of exposure occurring during every-day activities. The most common pathogen in blacklegged ticks was B. burgdorferi s.l. followed by hard-tick relapsing fever Borrelia . Negative binomial model performance was best in New England states followed by Middle Atlantic states. Conclusions Citizen science provides a low-cost and effective methodology for describing the seasonality and characteristics of human-tick exposure. In the Northeastern US, everyday activities were identified as a major mechanism for tick exposure, supporting the role of peri-domestic exposure in tick-borne disease. Citizen science provides a method for broad pathogen and tick surveillance, which is highly related to human disease, allowing for inferences to be made about the epidemiology of tick-borne disease. Electronic supplementary material The online version of this article (10.1186/s12942-019-0173-0) contains supplementary material, which is available to authorized users.

Tickborne disease awareness and protective practices among U.S. Forest Service employees from the upper Midwest, USA

“…If employees are frequently encountering adults in the spring, their perceptions of infection risk may be influenced by the fact that adults are easier to detect than nymphs. The nymph is the stage of I. scapularis most likely to transmit infections to humans because of their smaller size and greater likelihood of going undetected, and they tend to become active in late spring, which may include late May [45,46]. Employees may have selected spring because that answer included the month of May.…”

Passive Animal Surveillance to Identify Ticks in Wisconsin, 2011–2017

“…Active tick surveillance, including dragging or flagging, captures important information regarding density and ecological correlates for specific tick species, but such methods are labor intensive and not effective for many species. Passive surveillance, involving the submission of ticks from collaborators or the general public, is a tool that has been successfully implemented to provide information on tick and pathogen distribution as well as host associations in other areas [30,31,32,33,34,35,36,37,38,39,40]. The Wisconsin Department of Health Services and the University of Wisconsin Medical Entomology Laboratory implemented a passive surveillance program in 2011 with the goal of collecting ticks for examination of the extent of the distribution of a newly emerging pathogen, Ehrlichia muris eauclairensis [41].…”

Tickborne disease awareness and protective practices among U.S. Forest Service employees from the Upper Midwest, USA

“…If employees are frequently encountering adults in the spring, which are larger and more noticeable than the smaller nymphs, their perceptions of infection risk may be in uenced by the fact that adults are easier to detect than nymphs. The nymph is the stage of I. scapularis most likely to transmit infections to humans, and they tend to become active in late spring, which may include late May (45,46). Employees may have selected spring because that answer included the month of May.…”