Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) that affects members of the cervidae family. The infectious agent is a misfolded isoform (PrPSC) of the host prion protein (PrPC). The replication of PrPSC initiates a cascade of developmental changes that spread from cell to cell, individual to individual, and that for some TSEs, has crossed the species barrier. CWD can be transmitted horizontally and vertically, and it is the only TSE that affects free-ranging wildlife. While other TSEs are under control and even declining, infection rates of CWD continue to grow and the disease distribution continues to expand in North America and around the world. Since the first reported case in 1967, CWD has spread infecting captive and free-ranging cervids in 26 states in the US, 3 Canadian provinces, 3 European countries and has been found in captive cervids in South Korea. CWD causes considerable ecologic, economic and sociologic impact, as this is a 100% fatal highly contagious infectious disease, with no treatment or cure available. Because some TSEs have crossed the species barrier, the zoonotic potential of CWD is a concern for human health and continues to be investigated. Here we review the characteristics of the CWD prion protein, mechanisms of transmission and the role of genetics. We discuss the characteristics that contribute to prevalence and distribution. We also discuss the impact of CWD and review the management strategies that have been used to prevent and control the spread of CWD.

Bluetongue (BT) and epizootic hemorrhagic disease (EHD) cases have increased worldwide, causing significant economic loss to ruminant livestock production and detrimental effects to susceptible wildlife populations. In recent decades, hemorrhagic disease cases have been reported over expanding geographic areas in the United States. Effective BT and EHD prevention and control strategies for livestock and monitoring of these diseases in wildlife populations depend on an accurate understanding of the distribution of BT and EHD viruses in domestic and wild ruminants and their vectors, the Culicoides biting midges that transmit them. However, national maps showing the distribution of BT and EHD viruses and the presence of Culicoides vectors are incomplete or not available at all. Thus, efforts to accurately describe the potential risk of these viruses on ruminant populations are obstructed by the lack of systematic and routine surveillance of their hosts and vectors. In this review, we: (1) outline animal health impacts of BT and EHD in the USA; (2) describe current knowledge of the distribution and abundance of BT and EHD and their vectors in the USA; and (3) highlight the importance of disease (BT and EHD) and vector surveillance for ruminant populations.

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The North American river otter (Lontra canadensis) is a biomonitor for organohalogenated compounds (OHCs) associated with a wide range of deleterious health effects in wildlife and humans. We determined concentrations of twenty OHCs in livers of 23 river otters salvaged by the Illinois Department of Natural Resources from 2009 to 2011, determined sex-dependent distribution of OHCs, and compared our results to the reported concentrations of four OHCs in Illinois river otters from 1984 to 1989. Since these contaminants have been banned for over 30 years, we predicted smaller mean concentrations than those previously reported in Illinois otters. We detected eleven of twenty OHCs; PCBs (polychlorinated biphenyls), dieldrin, and 4,4'-DDE (dichlorodiphenyldichloroethylene) were present in the greatest mean concentrations. We report the largest mean concentration of dieldrin to date in the liver of North American river otters (mean: 174, range: 14.4-534 parts per billion wet wt [ppb]). Mean PCB concentrations were significantly higher in males (mean: 851; range: 30-3450 ppb) than females (mean: 282; range: 40-850 ppb; p=0.04). Mean concentrations of dieldrin were greater than those detected in otters from 1984 to 1989 (mean: 90; range: 30-130 ppb; p<0.05). Our results suggest OHC exposure remains a concern. Future research in Illinois should focus on evaluating OHCs exposures, particularly dieldrin, at the watershed level.

We compared methods commonly used in the field of river otter (Lontra canadensis) ecology to estimate visitation rates. We evaluated visitation rates estimated from 2 survey protocols based on video detection-individual visitation rate (IVR) and recording visitation rate (RVR)-and one indirect method based on scat detection-scat visitation rate (SVR). From August 2011 through August 2012, overall scat detection and cumulative video data from 403 camera-days in 2 latrine sites (River and Pond, at a study site adjacent to the Salt Fork of the Vermilion River near Fairmount, Illinois, USA) located <50 m apart did not reveal monthly or seasonal differences between SVR and video detection methods. We identified positive correlations among the 3 visitation rates and differences between overall IVR and RVR. All 3 methods resulted in peak visitation rates during winter. However, when these data were stratified by latrine site, we found both positive and negative correlations at the River latrine. Our work supports that SVR, IVR, and RVR are valuable methods to estimate otter visitation rates at latrine sites. However, it is clear that even within such a short distance between these 2 latrines, these methods detected differences in site utilization. The significant positive correlation observed between IVR and RVR (overall and by latrine site) suggests these methods can be used interchangeably. Otter detection using SVR may serve as a complementary assessment tool for IVR and RVR. To optimize cross-study comparisons and interpretation of results, future studies should detail the type of otter detection and visitation rate used, how variables are measured, formulas used in the calculation of the visitation rates, and detailed descriptions of scat counting efforts when using scat as a tool to evaluate otter visitation rates. Ó