Multiflora rose invasion amplifies prevalence of Lyme disease pathogen, but not necessarily Lyme disease risk

Abstract

BackgroundForests in urban landscapes differ from their rural counterparts in ways that may alter vector-borne disease dynamics. In urban forest fragments, tick-borne pathogen prevalence is not well characterized; mitigating disease risk in densely-populated urban landscapes requires understanding ecological factors that affect pathogen prevalence. We trapped blacklegged tick (Ixodes scapularis) nymphs in urban forest fragments on the East Coast of the United States and used multiplex real-time PCR assays to quantify the prevalence of four zoonotic, tick-borne pathogens. We used Bayesian logistic regression and WAIC model selection to understand how vegetation, habitat, and landscape features of urban forests relate to the prevalence of B. burgdorferi (the causative agent of Lyme disease) among blacklegged ticks.ResultsIn the 258 nymphs tested, we detected Borrelia burgdorferi (11.2% of ticks), Borrelia miyamotoi (0.8%) and Anaplasma phagocytophilum (1.9%), but we did not find Babesia microti (0%). Ticks collected from forests invaded by non-native multiflora rose (Rosa multiflora) had greater B. burgdorferi infection rates (mean = 15.9%) than ticks collected from uninvaded forests (mean = 7.9%). Overall, B. burgdorferi prevalence among ticks was positively related to habitat features (e.g. coarse woody debris and total understory cover) favorable for competent reservoir host species.ConclusionsUnderstory structure provided by non-native, invasive shrubs appears to aggregate ticks and reservoir hosts, increasing opportunities for pathogen transmission. However, when we consider pathogen prevalence among nymphs in context with relative abundance of questing nymphs, invasive plants do not necessarily increase disease risk. Although pathogen prevalence is greater among ticks in invaded forests, the probability of encountering an infected tick remains greater in uninvaded forests characterized by thick litter layers, sparse understories, and relatively greater questing tick abundance in urban landscapes.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-2623-0) contains supplementary material, which is available to authorized users.

Invasive Plants as Foci of Mosquito-Borne Pathogens: Red Cedar in the Southern Great Plains of the USA

“…Significantly influencing mosquito assemblages and providing nutritive inputs for larval mosquitoes (Reiskind and Zarrabi 2011;O'Brien and Reiskind 2013), ERC also affects the distribution of two important tick species (Noden and Dubie 2017) as well as horseflies (Sherrill 2019). While other invasive plants, mainly within tree habitat contexts, have been shown to influence vector and host distribution in the USA (Allan et al 2010;Reiskind et al 2010;Williams and Ward 2010;Gardner et al 2017;Adalsteinsson et al 2018), no mosquito-focused study has associated changes in vector distribution with levels of WPE by an invasive plant species throughout a region.…”

The role of host phenology for parasite transmission

“…3, 4, 6, 5). However, vector phenology is unlikely the only cause of the differences in B. burgdorferi transmission success among these regions as many other features that are known to impact B. burgdorferi also differ including host community composition, tick host preferences, and landscape and climatic features (James and Oliver Jr 1990;LoGiudice et al 2003;Brisson and Dykhuizen 2004;Ogden et al 2005b;Brisson et al 2008;Khatchikian et al 2012;Vuong et al 2014;Adalsteinsson et al 2016;Vuong et al 2017;Adalsteinsson et al 2018). Nevertheless, our results add to the body of literature that suggests tick phenology can impact B. burgdorferi fitness.…”

Assessing the current and potential future distribution of four invasive forest plants in Minnesota, U.S.A., using mixed sources of data

“…3 , 4 ) is concerning because the species frequently forms dense thickets along forest edges and in forest gaps, inhibiting the growth of other species 30 . Outside of forest-related concerns, recent research by Adalsteinsson et al (2018) 98 suggests that areas invaded by R. multiflora are associated with an increased prevalence of Borrelia burgdorferi , the bacterial source of Lyme disease, in black-legged ticks ( Ixodes scapularis ); though, the dense vegetation structure of R. multiflora -invaded stands does not necessarily make human disease risk more likely, as nymphs in dense invaded stands are hypothesized to feed primarily on smaller-bodied hosts such as mice. The predicted growth of suitable habitat for R. multiflora in northern Minnesota as time and climate progress, particularly along the shore of Lake Superior, is likely to be of concern in the future, as there is an abundance of forestland fragmented by recreational trails, roads, and harvest gaps in the region.…”