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1. Expanding range of Ixodes scapularis Say (Acari: Ixodidae) and Borrelia burgdorferi infection in North Carolina counties, 2018–2023

   https://doi.org/10.1371/journal.pone.0329511  

   Garshong, Reuben A; Adams, Dayvion R; Seagle, Steven W; Wasserberg, Gideon; Reiskind, Michael H; Teague, Jimmie L; Williams, Carl J; Barbarin, Alexis M (August 2025, PLOS One)

   Colunga-Salas, Pablo (Ed.)

   North Carolina (NC) has been experiencing a recent surge in human Lyme disease (LD) cases. Understanding the distribution of tick-borne diseases necessitates understanding the distribution of the ticks that transmit their causative pathogens. Unfortunately, in NC, knowledge on tick distribution is outdated. In this manuscript, we report the results of a state-wide entomologic survey conducted in 42 NC counties by flagging/dragging from spring 2018 to summer 2023.Ixodes scapularisnymphs and adults were screened forBorrelia burgdorferi(the causative agent of LD) and four other tick-borne bacterial pathogens (Anaplasma phagocytophilum,B. mayonii,B. miyamotoi, and Babesia microti) by the Centers for Disease Control and Prevention (CDC). Consistent with current data on human LD cases incidence and distribution, results of this study indicated a range expansion ofI. scapulariswith higher tick densities andB. burgdorferiinfection prevalence now occurring in the Blue Ridge Mountains province of western NC. Temporal analysis ofI. scapularispresence data indicated that this shift is fairly recent (about 10 years). Finally, in the Blue Ridge Mountains we detected a northeast-to-southwest gradient inI. scapularistick andB. burgdorferiinfection prevalence suggesting that this trend is driven by a spread of the northern cladeI. scapularisticks into NC from southwestern Virginia, along the Appalachian Mountains. Other pathogenic bacteria detected inI. scapularisticks includedB. miyamotoiandA. phagocytophilum, that were limited to the Blue Ridge Mountains.These results have important public health implications, including the need for enhanced tick surveillance, updated clinical awareness, and targeted public education in newly affected areas. 

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2. Longer study length, standardized sampling techniques, and broader geographic scope leads to higher likelihood of detecting stable abundance patterns in long term black-legged tick studies

   https://doi.org/10.7717/peerj.13916  

   Christie, Rowan; Stack Whitney, Kaitlin; Perrone, Julia; Bahlai, Christie A. (January 2022, PeerJ)

   Background Understanding how study design and monitoring strategies shape inference within, and synthesis across, studies is critical across biological disciplines. Many biological and field studies are short term and limited in scope. Monitoring studies are critical for informing public health about potential vectors of concern, such as Ixodes scapularis (black-legged ticks). Black-legged ticks are a taxon of ecological and human health concern due to their status as primary vectors of Borrelia burgdorferi , the bacteria that transmits Lyme disease. However, variation in black-legged tick monitoring, and gaps in data, are currently considered major barriers to understanding population trends and in turn, predicting Lyme disease risk. To understand how variable methodology in black-legged tick studies may influence which population patterns researchers find, we conducted a data synthesis experiment. Materials and Methods We searched for publicly available black-legged tick abundance dataset that had at least 9 years of data, using keywords about ticks in internet search engines, literature databases, data repositories and public health websites. Our analysis included 289 datasets from seven surveys from locations in the US, ranging in length from 9 to 24 years. We used a moving window analysis, a non-random resampling approach, to investigate the temporal stability of black-legged tick population trajectories across the US. We then used t-tests to assess differences in stability time across different study parameters. Results All of our sampled datasets required 4 or more years to reach stability. We also found several study factors can have an impact on the likelihood of a study reaching stability and of data leading to misleading results if the study does not reach stability. Specifically, datasets collected via dragging reached stability significantly faster than data collected via opportunistic sampling. Datasets that sampled larva reached stability significantly later than those that sampled adults or nymphs. Additionally, datasets collected at the broadest spatial scale (county) reached stability fastest. Conclusion We used 289 datasets from seven long term black-legged tick studies to conduct a non-random data resampling experiment, revealing that sampling design does shape inferences in black-legged tick population trajectories and how many years it takes to find stable patterns. Specifically, our results show the importance of study length, sampling technique, life stage, and geographic scope in understanding black-legged tick populations, in the absence of standardized surveillance methods. Current public health efforts based on existing black-legged tick datasets must take monitoring study parameters into account, to better understand if and how to use monitoring data to inform decisioning. We also advocate that potential future forecasting initiatives consider these parameters when projecting future black-legged tick population trends. 

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3. Resource selection by New York City deer reveals the effective interface between wildlife, zoonotic hazards and humans

   https://doi.org/10.1111/ele.14326  

   VanAcker, Meredith C; DeNicola, Vickie L; DeNicola, Anthony J; Aucoin, Sarah Grimké; Simon, Richard; Toal, Katrina L; Diuk‐Wasser, Maria A; Cagnacci, Francesca (December 2023, Ecology Letters)

   Abstract Although the role of host movement in shaping infectious disease dynamics is widely acknowledged, methodological separation between animal movement and disease ecology has prevented researchers from leveraging empirical insights from movement data to advance landscape scale understanding of infectious disease risk. To address this knowledge gap, we examine how movement behaviour and resource utilization by white‐tailed deer (Odocoileus virginianus) determines blacklegged tick (Ixodes scapularis) distribution, which depend on deer for dispersal in a highly fragmented New York City borough. Multi‐scale hierarchical resource selection analysis and movement modelling provide insight into how deer's movements contribute to the risk landscape for human exposure to the Lyme disease vector–I. scapularis. We find deer select highly vegetated and accessible residential properties which support blacklegged tick survival. We conclude the distribution of tick‐borne disease risk results from the individual resource selection by deer across spatial scales in response to habitat fragmentation and anthropogenic disturbances. 

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4. Risk of tick-borne pathogen spillover into urban yards in New York City

   https://doi.org/10.1186/s13071-022-05416-2  

   Gregory, Nichar; Fernandez, Maria P.; Diuk-Wasser, Maria (December 2022, Parasites & Vectors)

   Abstract Background The incidence of tick-borne disease has increased dramatically in recent decades, with urban areas increasingly recognized as high-risk environments for exposure to infected ticks. Green spaces may play a key role in facilitating the invasion of ticks, hosts and pathogens into residential areas, particularly where they connect residential yards with larger natural areas (e.g. parks). However, the factors mediating tick distribution across heterogeneous urban landscapes remain poorly characterized. Methods Using generalized linear models in a multimodel inference framework, we determined the residential yard- and local landscape-level features associated with the presence of three tick species of current and growing public health importance in residential yards across Staten Island, a borough of New York City, in the state of New York, USA. Results The amount and configuration of canopy cover immediately surrounding residential yards was found to strongly predict the presence of Ixodes scapularis and Amblyomma americanum , but not that of Haemaphysalis longicornis . Within yards, we found a protective effect of fencing against I. scapularis and A. americanum, but not against H. longicornis . For all species, the presence of log and brush piles strongly increased the odds of finding ticks in yards. Conclusions The results highlight a considerable risk of tick exposure in residential yards in Staten Island and identify both yard- and landscape-level features associated with their distribution. In particular, the significance of log and brush piles for all three species supports recommendations for yard management as a means of reducing contact with ticks. Graphical Abstract 

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5. Low Abundance of Three Tick Species in the Piedmont of North Carolina

   https://doi.org/10.1093/jme/tjaa171  

   Seagle, MP; Vierling, MR; Almeida, RJ; Clary, DJ; Hidell, W; Scott, EV; Vargas, C; Smith, KG (August 2020, Journal of medical entomology)

   Multiple species of ticks, including Ixodes scapularis (Say, Ixodida:Ixodidae), Amblyomma americanum (L., Ixodida:Ixodidae), and Dermacentor variabilis (Say, Ixodida:Ixodidae), occur in high and increasing abundance in both the northeast and southeast United States. North Carolina is at the nexus of spread of these species, with high occurrence and abundance of I. scapularis to the north and A. americanum to the south. Despite this, there are few records of these species in the Piedmont of North Carolina, including the greater Charlotte metropolitan area. Here, we update the known occurrence and abundance of these species in the North Carolina Piedmont. We surveyed for ticks using cloth drags, CO2 traps, and leaf litter samples at a total of 79 sites within five locations: Mecklenburg County, South Mountains State Park, Stone Mountain State Park, Duke Forest, and Morrow Mountain State Park, all in North Carolina, during the late spring, summer, and fall seasons of 2019. From these surveys, we had only 20 tick captures, illuminating the surprisingly low abundance of ticks in this region of North Carolina. Our results indicate the possibility of underlying habitat and host factors limiting tick distribution and abundance in the North Carolina Piedmont. 

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