A 117 year retrospective analysis of Pennsylvania tick community dynamics

Abstract

BackgroundTick-borne diseases have been increasing at the local, national, and global levels. Researchers studying ticks and tick-borne disease need a thorough knowledge of the pathogens, vectors, and epidemiology of disease spread. Three surveillance approaches are commonly used to provide insight into tick-borne disease risk: human disease case surveillance, active tick surveillance, and passive tick surveillance. Long-term passive surveillance can provide up-to-date data on the spatial variability and temporal dynamics of ectoparasite communities and shed light into the ecology of rarer tick species. We present a retrospective analysis on compiled data of ticks from Pennsylvania over the last 117 years.MethodsWe compiled data from ticks collected during tick surveillance research, and from citizen-based submissions to the Penn State University Department of Entomology (PSUEnt). Specimens were deposited at the PSUEnt arthropod collections that eventually became The Frost Entomological Museum. While most of the specimens were submitted by the public, a subset of the data were collected through active methods (flagging or dragging, or removal of ticks from wildlife). We analyzed all data from 1900-2017 for tick community composition, host associations, and spatio-temporal dynamics.ResultsIn total there were 4,491 submission lots consisting of 7,132 tick specimens. Twenty-four different species were identified, with the large proportion of submissions represented by five tick species. We observed a shift in tick community composition in which the dominant species of tick (Ixodes cookei) was overtaken in abundance by Dermacentor variabilis in the early 1990s, and then replaced in abundance by I. scapularis. We analyzed host data and identified overlaps in host range amongst tick species, suggesting potential hubs of pathogen transfer between different tick vectors and their reservoir hosts.ConclusionsWe highlight the importance of long-term passive tick surveillance in investigating the ecology of both common and rare tick species. Information on the geographic distribution, host-association, and seasonality of the tick community can help researchers and health-officials to identify high-risk areas.

The Gulf Coast tick, Amblyomma maculatum (Ixodida: Ixodidae) and spotted fever group Rickettsia in the highly urbanized northeastern US

“…The detection of established populations of A. maculatum in NYC may be less surprising than their apparent absence from New Jersey (which lies directly between areas with established populations in NYC and Delaware). A. maculatum have also been sporadically collected from NJ's western neighbor Pennsylvania although to date there are no known established populations (Pak et al 2019).…”

Surveillance for Borrelia spp. in Upland Game Birds in Pennsylvania, USA

“…Recently, a 117-year retrospective analysis was conducted evaluating changes in tick communities in Pennsylvania [ 38 ]. The study found that five species of ticks ( Dermacentor variabilis, Ixodes scapularis, I. cookei, Rhipicephalus sanguineus, and Amblyomma americanum ) were predominantly represented in collections from 1900–2017 [ 38 ]. Ticks recovered from wildlife made up only 6% (275/4491) of the total submissions, and of those submissions, ticks from avifauna were poorly represented.…”

Development of a practical framework for sustainable surveillance and control of ticks and tick-borne diseases in Africa

“…Active tick surveillance involves dragging, flagging, semiochemical-based trapping, and live animal capture. Passive tick surveillance, which is generally less costly, relies on farmers and volunteers who submit ticks for identification and pathogen screening [ 7 ]. Combined use of both surveillance approaches may be more effective in providing information on tick abundance in a given habitat.…”

“…Furthermore, a handful of T&TBDs surveillance programs, both past and present, have generated only limited data that are relevant at the national and regional levels; this may be because most surveys are restricted to particular geographic areas and/or brief periods of time. However, scientific evidence suggests that longterm passive tick surveillance is a meaningful and credible approach that might be used to explore the ecology of both common and rare tick species [ 7 ]. Although community members in both the United States and the United Kingdom provide significant contributions toward this effort by participating in passive tick surveillance, passive sampling, and community involvement in Africa is rare.…”