Complex ecological and human-influenced factors that are characteristic of chronic wasting disease (CWD) have created substantial and unique challenges for effective management in free-ranging cervids. We sought to summarize and characterize management experiences and actions from 30 U.S. states, 4Canadian provinces, and 3 European countries that have direct experience with CWD. We surveyed wildlife agencies that had detected CWD in their free-ranging cervid population and collected information from journal articles, published reports, and agency webpages. We report management approaches and their apparent impacts by state, provincial, or national jurisdiction during 3 stages of response to CWD: 1) predetection, 2) initial response, and 3) altered response. Agencies took a proactive approach to CWD during the pre-detection phase; 12 of the 24 responding agencies had a weightedsurveillance program in place and 17 had regulations aimed at disease prevention. There was no apparent difference in initial apparent prevalence of CWD among agencies with weighted surveillance in place and those without, but complicating factors, such as differing sampling methods and sample size, were present. Agencies reported 5 common surveillance strategies, and first detections were primarily from sampling hunter-harvested deer. Bans or restrictions on interstate movement of carcasses or live animals and increased bag
White-tailed deer (Odocoileus virginianus, WTD) spread communicable diseases such the zoonotic coronavirus SARS-CoV-2, which is a major public health concern, and chronic wasting disease (CWD), a fatal, highly contagious prion disease occurring in cervids. Currently, it is not well understood how WTD are spreading these diseases. In this paper, we speculate that “super-spreaders” mediate disease transmission via direct social interactions and indirectly via body fluids exchanged at scrape sites. Super-spreaders are infected individuals that infect more contacts than other infectious individuals within a population. In this study, we used network analysis from scrape visitation data to identify potential super-spreaders among multiple communities of a rural WTD herd. We combined local network communities to form a large region-wide social network consisting of 96 male WTD. Analysis of WTD bachelor groups and random network modeling demonstrated that scraping networks depict real social networks, allowing detection of direct and indirect contacts, which could spread diseases. Using this regional network, we model three major types of potential super-spreaders of communicable disease: in-degree, out-degree, and betweenness potential super-spreaders. We found out-degree and betweenness potential super-spreaders to be critical for disease transmission across multiple communities. Analysis of age structure revealed that potential super-spreaders were mostly young males, less than 2.5 years of age. We also used social network analysis to measure the outbreak potential across the landscape using a new technique to locate disease transmission hotspots. To model indirect transmission risk, we developed the first scrape-to-scrape network model demonstrating connectivity of scrape sites. Comparing scrape betweenness scores allowed us to locate high-risk transmission crossroads between communities. We also monitored predator activity, hunting activity, and hunter harvests to better understand how predation influences social networks and potential disease transmission. We found that predator activity significantly influenced the age structure of scraping communities. We assessed disease-management strategies by social-network modeling using hunter harvests or removal of potential super-spreaders, which fragmented WTD social networks reducing the potential spread of disease. Overall, this study demonstrates a model capable of predicting potential super-spreaders of diseases, outlines methods to locate transmission hotspots and community crossroads, and provides new insight for disease management and outbreak prevention strategies.
Tick-borne diseases are on the rise globally; however, information is lacking about tick questing behavior. In this laboratory study, we explored tick preferences for stem type (plastic grass, wooden, and metal), questing height, and head orientation. Using 60 Amblyomma americanum adults over three 72-hour replicates, we determined that 21.7% of ticks quested at any given time and that ticks exhibited a strong preference to quest with their heads oriented downwards, irrespective of stem type. Individual ticks tended to quest on only one stem in this study, and a maximum of three. Nonetheless, ticks appeared to prefer questing on wooden and plastic grass stems over metal stems. We did not find an effect of time of day on tick questing rates. Increased understanding of tick questing behavior can improve vector control efforts.
Wildlife species are host to a variety of gastrointestinal parasites (GIPs). Artificially concentrating animals may increase the risk of disease spread due to increased GIP load and associated environmental load. Supplemental feeding of deer is common among hunters and known to concentrate animals, but there is limited knowledge of how it affects GIP environmental load. GIP load was compared between ecologically-equivalent pairs of sites in Mississippi with and without year-round supplemental feeding (average distance between pairs = 147 m). During May-August in 2019 and 2020, feces from white-tailed deer and raccoons were collected and examined for the presence of nematodes, coccidia, Giardia spp., Cryptosporidium spp., and Baylisascaris procyonis. On average, fed sites had 8 more deer (241% increase) and 2 more raccoon fecal piles (540% increase) than unfed sites. Average parasite loads for individual fecal samples did not differ between fed and unfed sites, but the greater number of deer and raccoon fecal piles at fed sites (p < 0.0001) produced 231% and 308% greater environmental loads of nematodes and coccidia, respectively. Spin feeders, the only feeder type that distributed feed on the ground, had 326% more coccidia in feces on average compared to other feeder types (p < 0.03). These results show that supplemental feeding of white-tailed deer, especially with spin feeders, increases environmental loads of GIP and the potential for transmission of parasitic diseases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.