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Hopp P, Rolandsen CM, Korpenfelt SL, Våge J, Sörén K, Solberg EJ, Averhed G, Pusenius J, Rosendal T, Ericsson G, Bakka HC, Mysterud A, Gavier-Widén D, Hautaniemi M, Ågren E, Isomursu M, Madslien K, Benestad SL, Nöremark M. Sporadic cases of chronic wasting disease in old moose - an epidemiological study. J Gen Virol 2024; 105. [PMID: 38265285 DOI: 10.1099/jgv.0.001952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024] Open
Abstract
Transmissible spongiform encephalopathies or prion diseases comprise diseases with different levels of contagiousness under natural conditions. The hypothesis has been raised that the chronic wasting disease (CWD) cases detected in Nordic moose (Alces alces) may be less contagious, or not contagious between live animals under field conditions. This study aims to investigate the epidemiology of CWD cases detected in moose in Norway, Sweden and Finland using surveillance data from 2016 to 2022.In total, 18 CWD cases were detected in Nordic moose. All moose were positive for prion (PrPres) detection in the brain, but negative in lymph nodes, all were old (mean 16 years; range 12-20) and all except one, were female. Age appeared to be a strong risk factor, and the sex difference may be explained by few males reaching high age due to hunting targeting calves, yearlings and males.The cases were geographically scattered, distributed over 15 municipalities. However, three cases were detected in each of two areas, Selbu in Norway and Arjeplog-Arvidsjaur in Sweden. A Monte Carlo simulation approach was applied to investigate the likelihood of such clustering occurring by chance, given the assumption of a non-contagious disease. The empirical P-value for obtaining three cases in one Norwegian municipality was less than 0.05, indicating clustering. However, the moose in Selbu were affected by different CWD strains, and over a 6 year period with intensive surveillance, the apparent prevalence decreased, which would not be expected for an ongoing outbreak of CWD. Likewise, the three cases in Arjeplog-Arvidsjaur could also indicate clustering, but management practices promotes a larger proportion of old females and the detection of the first CWD case contributed to increased awareness and sampling.The results of our study show that the CWD cases detected so far in Nordic moose have a different epidemiology compared to CWD cases reported from North America and in Norwegian reindeer (Rangifer tarandus tarandus). The results support the hypothesis that these cases are less contagious or not contagious between live animals under field conditions. To enable differentiation from other types of CWD, we support the use of sporadic CWD (sCWD) among the names already in use.
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Affiliation(s)
- Petter Hopp
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431 Ås, Norway
| | - Christer Moe Rolandsen
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Torgarden, NO-7485 Trondheim, Norway
| | | | - Jørn Våge
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431 Ås, Norway
| | - Kaisa Sörén
- National Veterinary Institute (SVA), Uppsala, Sweden
| | - Erling Johan Solberg
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Torgarden, NO-7485 Trondheim, Norway
| | | | - Jyrki Pusenius
- Natural Resources Institute Finland (LUKE), Yliopistokatu 6, FI-80100 Joensuu, Finland
| | | | - Göran Ericsson
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden
| | - Haakon Christopher Bakka
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431 Ås, Norway
- Present address: Kontali, Fred Olsens gate 1, NO-0152 Oslo, Norway
| | - Atle Mysterud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
| | | | | | - Erik Ågren
- National Veterinary Institute (SVA), Uppsala, Sweden
| | | | - Knut Madslien
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431 Ås, Norway
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O'Brien DJ, Thacker TC, Salvador LCM, Duffiney AG, Robbe-Austerman S, Camacho MS, Lombard JE, Palmer MV. The devil you know and the devil you don't: current status and challenges of bovine tuberculosis eradication in the United States. Ir Vet J 2023; 76:16. [PMID: 37491296 PMCID: PMC10369704 DOI: 10.1186/s13620-023-00247-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 07/10/2023] [Indexed: 07/27/2023] Open
Abstract
Having entered into its second century, the eradication program for bovine tuberculosis (bTB, caused by Mycobacterium bovis) in the United States of America occupies a position both enviable and daunting. Excepting four counties in Michigan comprising only 6109 km2 (0.06% of US land area) classified as Modified Accredited, as of April 2022 the entire country was considered Accredited Free of bTB by the US Department of Agriculture for cattle and bison. On the surface, the now well-described circumstances of endemic bTB in Michigan, where white-tailed deer (Odocoileus virginianus) serve as a free-ranging wildlife maintenance host, may appear to be the principal remaining barrier to national eradication. However, the situation there is unique in the U.S., and far-removed from the broader issues of bTB control in the remainder of the country. In Michigan, extensive surveillance for bTB in deer over the last quarter century, and regulatory measures to maximize the harvest of publicly-owned wildlife, have been implemented and sustained. Prevalence of bTB in deer has remained at a low level, although not sufficiently low to eliminate cattle herd infections. Public attitudes towards bTB, cattle and deer, and their relative importance, have been more influential in the management of the disease than any limitations of biological science. However, profound changes in the demographics and social attitudes of Michigan's human population are underway, changes which are likely to force a critical reevaluation of the bTB control strategies thus far considered integral. In the rest of the U.S. where bTB is not self-sustaining in wildlife, changes in the scale of cattle production, coupled with both technical and non-technical issues have created their own substantial challenges. It is against this diverse backdrop that the evolution of whole genome sequencing of M. bovis has revolutionized understanding of the history and ecology of bTB in Michigan, resolved previously undiscernible epidemiological puzzles, provided insights into zoonotic transmission, and unified eradication efforts across species and agencies. We describe the current status of bTB eradication in the U.S., how circumstances and management have changed, what has been learned, and what remains more elusive than ever.
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Affiliation(s)
- Daniel J O'Brien
- Michigan Department of Natural Resources, Wildlife Disease Laboratory, 4125 Beaumont Road, Room 250, Lansing, MI, 48910-8106, USA.
- Retired. Current address: Department of Fisheries and Wildlife, Michigan State University, 480 Wilson Road, East Lansing, MI, 48824, USA.
| | - Tyler C Thacker
- United States Department of Agriculture, Animal and Plant Health Inspection Service, National Veterinary Services Laboratories, 1920 Dayton Avenue, Ames, IA, 50010, USA
| | - Liliana C M Salvador
- Institute of Bioinformatics, Center for the Ecology of Infectious Diseases, Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
- School of Animal & Comparative Biomedical Sciences, University of Arizona, Shantz Building, 1177 E 4th St, Tucson, AZ, 85719, USA
| | - Anthony G Duffiney
- United States Department of Agriculture, Animal and Plant Health Inspection Service-Wildlife Services, 2803 Jolly Road, Suite 100, Okemos, MI, 48864, USA
| | - Suelee Robbe-Austerman
- United States Department of Agriculture, Animal and Plant Health Inspection Service, National Veterinary Services Laboratories, 1920 Dayton Avenue, Ames, IA, 50010, USA
| | - Mark S Camacho
- United States Department of Agriculture, Cattle Health Center, Animal and Plant Health Inspection Service-Veterinary Services, Centennial Campus, Raleigh, NC, 27606, USA
| | - Jason E Lombard
- United States Department of Agriculture, Field Epidemiologic Investigation, Animal and Plant Health Inspection Service, Veterinary Services, 2150 Centre Avenue, Bldg. B, Fort Collins, CO, 80526, USA
| | - Mitchell V Palmer
- United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, 1920 Dayton Avenue, Ames, IA, 50010, USA
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Hearst S, Huang M, Johnson B, Rummells E. Identifying Potential Super-Spreaders and Disease Transmission Hotspots Using White-Tailed Deer Scraping Networks. Animals (Basel) 2023; 13:1171. [PMID: 37048427 PMCID: PMC10093032 DOI: 10.3390/ani13071171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/22/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
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.
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Affiliation(s)
- Scoty Hearst
- The Department of Chemistry and Biochemistry, Mississippi College, Clinton, MS 39056, USA
| | - Miranda Huang
- Department of Wildlife, Fisheries, and Aquaculture, Mississippi State University, Starkville, MS 39762, USA
| | - Bryant Johnson
- The Department of Chemistry and Biochemistry, Mississippi College, Clinton, MS 39056, USA
| | - Elijah Rummells
- The Department of Chemistry and Biochemistry, Mississippi College, Clinton, MS 39056, USA
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Ketz AC, Storm DJ, Barker RE, Apa AD, Oliva‐Aviles C, Walsh DP. Assimilating ecological theory with empiricism: Using constrained generalized additive models to enhance survival analyses. Methods Ecol Evol 2023. [DOI: 10.1111/2041-210x.14057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Alison C. Ketz
- Wisconsin Cooperative Research Unit, Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| | - Daniel J. Storm
- Wisconsin Department of Natural Resources Rhinelander Wisconsin USA
| | - Rachel E. Barker
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| | | | | | - Daniel P. Walsh
- U.S. Geological Survey Montana Cooperative Wildlife Research Unit Missoula Montana USA
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CAUSE OF DEATH, PATHOLOGY, AND CHRONIC WASTING DISEASE STATUS OF WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) MORTALITIES IN WISCONSIN, USA. J Wildl Dis 2022; 58:803-815. [PMID: 36288680 DOI: 10.7589/jwd-d-21-00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 06/30/2022] [Indexed: 12/04/2022]
Abstract
White-tailed deer (WTD; Odocoileus virginianus) are a critical species for ecosystem function and wildlife management. As such, studies of cause-specific mortality among WTD have long been used to understand population dynamics. However, detailed pathological information is rarely documented for free-ranging WTD, especially in regions with a high prevalence of chronic wasting disease (CWD). This leaves a significant gap in understanding how CWD is associated with disease processes or comorbidities that may subsequently alter broader population dynamics. We investigated unknown mortalities among collared WTD in southwestern Wisconsin, USA, an area of high CWD prevalence. We tested for associations between CWD and other disease processes and used a network approach to test for co-occurring disease processes. Predation and infectious disease were leading suspected causes of death, with high prevalence of CWD (42.4%; of 245 evaluated) and pneumonia (51.2%; of 168 evaluated) in our sample. CWD prevalence increased with age, before decreasing among older individuals, with more older females than males in our sample. Females were more likely to be CWD positive, and although this was not statistically significant when accounting for age, females were significantly more likely to die with end-stage CWD than males and may consequently be an underrecognized source of CWD transmission. Presence of CWD was associated with emaciation, atrophy of marrow fat and hematopoietic cells, and ectoparasitism (lice and ticks). Occurrences of severe infectious disease processes clustered together (e.g., pneumonia, CWD), as compared to noninfectious or low-severity processes (e.g., sarcocystosis), although pneumonia cases were not fully explained by CWD status. With the prevalence of CWD increasing across North America, our results highlight the critical importance of understanding the potential role of CWD in favoring or maintaining disease processes of importance for deer population health and dynamics.
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6
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Combining seroprevalence and capture-mark-recapture data to estimate the force of infection of brucellosis in a managed population of Alpine ibex. Epidemics 2022; 38:100542. [DOI: 10.1016/j.epidem.2022.100542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 01/04/2022] [Accepted: 02/03/2022] [Indexed: 11/17/2022] Open
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Rogers W, Brandell EE, Cross PC. Epidemiological differences between sexes affect management efficacy in simulated chronic wasting disease systems. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14125] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Will Rogers
- Department of Ecology Montana State University Bozeman Montana USA
| | - Ellen E. Brandell
- Department of Biology, Center for Infectious Disease Dynamics, Pennsylvania State University University Park Pennsylvania USA
- Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology University of Wisconsin‐Madison Madison WI USA
| | - Paul C. Cross
- U.S. Geological Survey, Northern Rocky Mountain Science Center Bozeman Montana USA
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Ketz AC, Robinson SJ, Johnson CJ, Samuel MD. Pathogen‐mediated selection and management implications for white‐tailed deer exposed to chronic wasting disease. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Alison C. Ketz
- Wisconsin Cooperative Research Unit Department of Forest and Wildlife Ecology University of Wisconsin Madison WI USA
| | - Stacie J. Robinson
- NOAA Hawaiian Monk Seal Research Program Pacific Islands Fisheries Science Center Honolulu HI USA
| | - Chad J. Johnson
- Medical Microbiology and Immunology University of Wisconsin Madison WI USA
| | - Michael D. Samuel
- Department of Forest and Wildlife Ecology University of Wisconsin Madison WI USA
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Tranulis MA, Gavier-Widén D, Våge J, Nöremark M, Korpenfelt SL, Hautaniemi M, Pirisinu L, Nonno R, Benestad SL. Chronic wasting disease in Europe: new strains on the horizon. Acta Vet Scand 2021; 63:48. [PMID: 34823556 PMCID: PMC8613970 DOI: 10.1186/s13028-021-00606-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/30/2021] [Indexed: 01/05/2023] Open
Abstract
Prion diseases are fatal neurodegenerative disorders with known natural occurrence in humans and a few other mammalian species. The diseases are experimentally transmissible, and the agent is derived from the host-encoded cellular prion protein (PrPC), which is misfolded into a pathogenic conformer, designated PrPSc (scrapie). Aggregates of PrPSc molecules, constitute proteinaceous infectious particles, known as prions. Classical scrapie in sheep and goats and chronic wasting disease (CWD) in cervids are known to be infectious under natural conditions. In CWD, infected animals can shed prions via bodily excretions, allowing direct host-to-host transmission or indirectly via prion-contaminated environments. The robustness of prions means that transmission via the latter route can be highly successful and has meant that limiting the spread of CWD has proven difficult. In 2016, CWD was diagnosed for the first time in Europe, in reindeer (Rangifer tarandus) and European moose (Alces alces). Both were diagnosed in Norway, and, subsequently, more cases were detected in a semi-isolated wild reindeer population in the Nordfjella area, in which the first case was identified. This population was culled, and all reindeer (approximately 2400) were tested for CWD; 18 positive animals, in addition to the first diagnosed case, were found. After two years and around 25,900 negative tests from reindeer (about 6500 from wild and 19,400 from semi-domesticated) in Norway, a new case was diagnosed in a wild reindeer buck on Hardangervidda, south of the Nordfjella area, in 2020. Further cases of CWD were also identified in moose, with a total of eight in Norway, four in Sweden, and two cases in Finland. The mean age of these cases is 14.7 years, and the pathological features are different from North American CWD and from the Norwegian reindeer cases, resembling atypical prion diseases such as Nor98/atypical scrapie and H- and L-forms of BSE. In this review, these moose cases are referred to as atypical CWD. In addition, two cases were diagnosed in red deer (Cervus elaphus) in Norway. The emergence of CWD in Europe is a threat to European cervid populations, and, potentially, a food-safety challenge, calling for a swift, evidence-based response. Here, we review data on surveillance, epidemiology, and disease characteristics, including prion strain features of the newly identified European CWD agents.
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Smolko P, Seidel D, Pybus M, Hubbs A, Ball M, Merrill E. Spatio-temporal changes in chronic wasting disease risk in wild deer during 14 years of surveillance in Alberta, Canada. Prev Vet Med 2021; 197:105512. [PMID: 34740023 DOI: 10.1016/j.prevetmed.2021.105512] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 11/18/2022]
Abstract
Disease risk modeling is a key first step to understand the spatio-temporal dynamics of wildlife disease and to direct cost-effective surveillance and management. In Alberta, active surveillance for chronic wasting disease (CWD) in wild cervids began in 1998 with the first case detected in free-ranging cervids in 2005. Following the detection, a herd reduction program was implemented during 2005-2008 and in 2006 the ongoing hunter-based CWD Surveillance Program became mandatory in high-risk Wildlife Management Units (WMU). We used data collected during the CWD surveillance program to 1) document growth in sex-specific CWD prevalence (proportion of deer in sample that is CWD-positive) in hunter-harvest deer in 6 WMUs consistently monitored from 2006 to 2018, 2) document landscape features associated with where CWD-positive compared to CWD-negative deer were removed during hunter harvest and herd reduction in an early (2005-2012) and in a late period (2013-2017), and 3) to map the spatial risk of harvesting a deer infected with CWD in the prairie parklands of Alberta. In the 6 continuously monitored WMUs, risk of a harvested deer being CWD positive increased from 2006 to 2018 with CWD prevalence remaining highest in male mule deer whereas overall growth rate in CWD prevalence was greater in female mule deer, but similar to male white-tailed deer. We found no evidence that the 3-year herd reduction program conducted immediately after CWD was first detected affected the rate at which CWD grew over the course of the invasion. Risk of deer being CWD-positive was the highest in animals taken near small stream drainages and on soils with low organic carbon content in the early period, whereas risk became highest in areas of agriculture especially when far from large river drainages where deer often concentrate in isolated woody patches. The change in the influence of proximity to known CWD-positive cases suggested the disease was initially patchy but became more spatially homogeneous over time. Our results indicate that a targeted-removal program will remove more CWD positive animals compared to hunter harvest. However, the discontinuation of targeted removals during our research program, restricted our ability to assess its long term impact on CWD prevalence.
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Affiliation(s)
- Peter Smolko
- University of Alberta, Department of Biological Sciences, Edmonton, AB T6G 2E9, Canada; Technical University in Zvolen, Department of Applied Zoology and Wildlife Management, 960 01, Zvolen, Slovakia
| | - Dana Seidel
- Department of Environmental Science, Policy, & Management, University of California, Berkeley, CA, USA
| | - Margo Pybus
- University of Alberta, Department of Biological Sciences, Edmonton, AB T6G 2E9, Canada; Alberta Fish and Wildlife Division, Government of Alberta, Edmonton, AB T6H 4P2, Canada
| | - Anne Hubbs
- Alberta Fish and Wildlife Division, Government of Alberta, Edmonton, AB T6H 4P2, Canada
| | - Mark Ball
- Alberta Fish and Wildlife Division, Government of Alberta, Edmonton, AB T6H 4P2, Canada
| | - Evelyn Merrill
- University of Alberta, Department of Biological Sciences, Edmonton, AB T6G 2E9, Canada.
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Viljugrein H, Hopp P, Benestad SL, Våge J, Mysterud A. Risk-based surveillance of chronic wasting disease in semi-domestic reindeer. Prev Vet Med 2021; 196:105497. [PMID: 34564054 DOI: 10.1016/j.prevetmed.2021.105497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/27/2021] [Accepted: 09/15/2021] [Indexed: 10/20/2022]
Abstract
Reindeer pastoralism is a widespread practise across Fennoscandia and Russia. An outbreak of chronic wasting disease (CWD) among wild reindeer (Rangifer tarandus) poses a severe threat to the semi-domestic reindeer herding culture. Establishing surveillance is therefore key, but current models for surveillance of CWD are designed for wild cervids and rely on samples obtained from recreational hunters. Targeting animal groups with a higher infection probability is often used for more efficient disease surveillance. CWD has a long incubation period of 2-3 years, and the animals show clinical signs in the later stages of the infection i.e. 1-4 months prior to death. The semi-domestic reindeer are free-ranging most of the year, but during slaughtering in late fall, herders stress the animals in penned areas. This allows removal of animals with deviant behaviour or physical appearance, and such removals are likely to include animals in the clinical stages of CWD if the population is infected. In Norway, the semi-domestic reindeer in Filefjell is adjacent to a previously CWD infected wild population. We developed a risk-based surveillance method for this semi-domestic setting to establish the probability of freedom from infection over time, or enable early disease detection and mitigation. The surveillance scheme with a scenario tree using three risk categories (sample category, demographic group, and deviations in behaviour or physical appearance) was more effective and less invasive as compared to the surveillance method developed for wild reindeer. We also simulated how variation in susceptibility, incubation period and time for onset of clinical signs (linked to variation in the prion protein gene, PRNP) would potentially affect surveillance. Surveillance for CWD was mandatory within EU-member states with reindeer (2018-2020). The diversity of management systems and epidemiological settings will require the development of a set of surveillance systems suitable for each different context. Our surveillance model is designed for a population with a high risk of CWD introduction requiring massive sampling, while at the same time aiming to limit adverse effects to the populations in areas of surveillance.
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Affiliation(s)
- Hildegunn Viljugrein
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431, Ås, Norway; Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, NO-0316, Oslo, Norway.
| | - Petter Hopp
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431, Ås, Norway
| | | | - Jørn Våge
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431, Ås, Norway
| | - Atle Mysterud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, NO-0316, Oslo, Norway; Norwegian Institute for Nature Research (NINA), P. O. Box 5685, Sluppen, NO-7485, Trondheim, Norway
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Sillero N, Arenas-Castro S, Enriquez‐Urzelai U, Vale CG, Sousa-Guedes D, Martínez-Freiría F, Real R, Barbosa A. Want to model a species niche? A step-by-step guideline on correlative ecological niche modelling. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2021.109671] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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13
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CHRONIC WASTING DISEASE MODELING: AN OVERVIEW. J Wildl Dis 2021; 56:741-758. [PMID: 32544029 DOI: 10.7589/2019-08-213] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/13/2019] [Indexed: 11/20/2022]
Abstract
Chronic wasting disease (CWD) is an infectious and fatal prion disease occurring in the family Cervidae. To update the research community regarding the status quo of CWD epidemic models, we conducted a meta-analysis on CWD research. We collected data from peer-reviewed articles published since 1980, when CWD was first diagnosed, until December 2018. We explored the analytical methods used historically to understand CWD. We used 14 standardized variables to assess overall analytical approaches of CWD research communities, data used, and the modeling methods used. We found that CWD modeling initiated in the early 2000s and has increased since then. Connectivity of the research community was heavily reliant on a cluster of CWD researchers. Studies focused primarily on regression and compartment-based models, population-level approaches, and host species of game management concern. Similarly, CWD research focused on single populations, species, and locations, neglecting modeling using community ecology and biogeographic approaches. Chronic wasting disease detection relied on classic diagnostic methods with limited sensitivity for most stages of infection. Overall, we found that past modeling efforts generated a solid baseline for understanding CWD in wildlife and increased our knowledge on infectious prion ecology. Future analytical efforts should consider more sensitive diagnostic methods to quantify uncertainty and broader scale studies to elucidate CWD transmission beyond population-level approaches. Considering that infectious prions may not follow biological rules of well-known wildlife pathogens (i.e., viruses, bacteria, fungi), assumptions used when modeling other infectious disease may not apply for CWD. Chronic wasting disease is a new challenge in wildlife epidemiology.
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Belsare AV, Millspaugh JJ, Mason JR, Sumners J, Viljugrein H, Mysterud A. Getting in Front of Chronic Wasting Disease: Model-Informed Proactive Approach for Managing an Emerging Wildlife Disease. Front Vet Sci 2021; 7:608235. [PMID: 33585599 PMCID: PMC7874108 DOI: 10.3389/fvets.2020.608235] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 12/07/2020] [Indexed: 11/23/2022] Open
Abstract
Continuing geographic spread of chronic wasting disease (CWD) poses a serious threat to the sustainable future of cervids and hunting in North America. Moreover, CWD has been detected in captive cervids in South Korea and, in recent years, in free-ranging reindeer in Europe (Norway). Management of this disease is limited by logistical, financial, and sociopolitical considerations, and current strategies primarily focus on reducing host densities through hunter harvest and targeted culling. The success of such strategies in mitigating the spread and prevalence of CWD only upon detection is questionable. Here, we propose a proactive approach that emphasizes pre-emptive management through purposeful integration of virtual experiments (simulating alternate interventions as model scenarios) with the aim of evaluating their effectiveness. Here, we have used a published agent-based model that links white-tailed deer demography and behavior with CWD transmission dynamics to first derive a CWD outbreak trajectory and then use the trajectory to highlight issues associated with different phases of the CWD outbreak (pre-establishment/transition/endemic). Specifically, we highlight the practical constraints on surveillance in the pre-establishment phase and recommend that agencies use a realistic detection threshold for their CWD surveillance programs. We further demonstrate that many disease introductions are "dead ends" not leading to a full epidemic due to high stochasticity and harvesting in the pre-establishment phase of CWD. Model evaluated pre-emptive (pre-detection) harvest strategies could increase the resilience of the deer population to CWD spread and establishment. We conclude it is important to adaptively position CWD management ahead of, rather than behind, the CWD front.
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Affiliation(s)
- Aniruddha V. Belsare
- Department of Fisheries and Wildlife, Boone and Crockett Quantitative Wildlife Center, Michigan State University, East Lansing, MI, United States
| | - Joshua J. Millspaugh
- W.A. Franke College of Forestry and Conservation, Wildlife Biology Program, University of Montana, Missoula, MT, United States
| | - J. R. Mason
- Michigan Department of Natural Resources Executive in Residence, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, United States
| | - Jason Sumners
- Missouri Department of Conservation, Columbia, MO, United States
| | | | - Atle Mysterud
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo, Oslo, Norway
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15
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Hunting strategies to increase detection of chronic wasting disease in cervids. Nat Commun 2020; 11:4392. [PMID: 32873810 PMCID: PMC7463264 DOI: 10.1038/s41467-020-18229-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 08/12/2020] [Indexed: 11/17/2022] Open
Abstract
The successful mitigation of emerging wildlife diseases may involve controversial host culling. For livestock, ‘preemptive host culling’ is an accepted practice involving the removal of herds with known contact to infected populations. When applied to wildlife, this proactive approach comes in conflict with biodiversity conservation goals. Here, we present an alternative approach of ‘proactive hunting surveillance’ with the aim of early disease detection that simultaneously avoids undesirable population decline by targeting demographic groups with (1) a higher likelihood of being infected and (2) a lower reproductive value. We applied this harvesting principle to populations of reindeer to substantiate freedom of chronic wasting disease (CWD) infection. Proactive hunting surveillance reached 99% probability of freedom from infection (<4 reindeer infected) within 3–5 years, in comparison to ~10 years using ordinary harvest surveillance. However, implementation uncertainties linked to social issues appear challenging also with this kind of host culling. Rarely are the outcomes of mathematical (probability) models of wildlife disease detection used to inform policy or management changes. Here the authors develop a proactive hunting surveillance program that shortened the time required to establish freedom from chronic wasting disease at the population level in reindeer.
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16
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Mysterud A, Madslien K, Viljugrein H, Vikøren T, Andersen R, Güere ME, Benestad SL, Hopp P, Strand O, Ytrehus B, Røed KH, Rolandsen CM, Våge J. The demographic pattern of infection with chronic wasting disease in reindeer at an early epidemic stage. Ecosphere 2019. [DOI: 10.1002/ecs2.2931] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Atle Mysterud
- Centre for Ecological and Evolutionary Synthesis (CEES) Department of Biosciences University of Oslo NO‐0316 P.O. Box 1066 Blindern Oslo Norway
| | - Knut Madslien
- Norwegian Veterinary Institute NO‐0106 P.O. Box 750 Sentrum Oslo Norway
| | | | - Turid Vikøren
- Norwegian Veterinary Institute NO‐0106 P.O. Box 750 Sentrum Oslo Norway
| | - Roy Andersen
- Norwegian Institute for Nature Research (NINA) NO‐7485 P. O. Box 5685 Torgarden Trondheim Norway
| | - Mariella Evelyn Güere
- Department of Basic Sciences and Aquatic Medicine Norwegian University of Life Sciences NO‐0102 P.O. Box 369 Sentrum Oslo Norway
| | | | - Petter Hopp
- Norwegian Veterinary Institute NO‐0106 P.O. Box 750 Sentrum Oslo Norway
| | - Olav Strand
- Norwegian Institute for Nature Research (NINA) NO‐7485 P. O. Box 5685 Torgarden Trondheim Norway
| | - Bjørnar Ytrehus
- Norwegian Institute for Nature Research (NINA) NO‐7485 P. O. Box 5685 Torgarden Trondheim Norway
| | - Knut H. Røed
- Department of Basic Sciences and Aquatic Medicine Norwegian University of Life Sciences NO‐0102 P.O. Box 369 Sentrum Oslo Norway
| | - Christer M. Rolandsen
- Norwegian Institute for Nature Research (NINA) NO‐7485 P. O. Box 5685 Torgarden Trondheim Norway
| | - Jørn Våge
- Norwegian Veterinary Institute NO‐0106 P.O. Box 750 Sentrum Oslo Norway
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17
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Walker NB, Hefley TJ, Walsh DP. Bias correction of bounded location error in binary data. Biometrics 2019; 76:530-539. [PMID: 31517389 DOI: 10.1111/biom.13152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 09/03/2019] [Indexed: 11/29/2022]
Abstract
Binary regression models for spatial data are commonly used in disciplines such as epidemiology and ecology. Many spatially referenced binary data sets suffer from location error, which occurs when the recorded location of an observation differs from its true location. When location error occurs, values of the covariates associated with the true spatial locations of the observations cannot be obtained. We show how a change of support (COS) can be applied to regression models for binary data to provide coefficient estimates when the true values of the covariates are unavailable, but the unknown location of the observations are contained within nonoverlapping arbitrarily shaped polygons. The COS accommodates spatial and nonspatial covariates and preserves the convenient interpretation of methods such as logistic and probit regression. Using a simulation experiment, we compare binary regression models with a COS to naive approaches that ignore location error. We illustrate the flexibility of the COS by modeling individual-level disease risk in a population using a binary data set where the locations of the observations are unknown but contained within administrative units. Our simulation experiment and data illustration corroborate that conventional regression models for binary data that ignore location error are unreliable, but that the COS can be used to eliminate bias while preserving model choice.
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Affiliation(s)
- Nelson B Walker
- Department of Statistics, Kansas State University, Manhattan, Kansas
| | - Trevor J Hefley
- Department of Statistics, Kansas State University, Manhattan, Kansas
| | - Daniel P Walsh
- U.S. Geological Survey, National Wildlife Health Center, Madison, Wisconsin
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18
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Mysterud A, Edmunds DR. A review of chronic wasting disease in North America with implications for Europe. EUR J WILDLIFE RES 2019. [DOI: 10.1007/s10344-019-1260-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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19
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Viljugrein H, Hopp P, Benestad SL, Nilsen EB, Våge J, Tavornpanich S, Rolandsen CM, Strand O, Mysterud A. A method that accounts for differential detectability in mixed samples of long‐term infections with applications to the case of chronic wasting disease in cervids. Methods Ecol Evol 2018. [DOI: 10.1111/2041-210x.13088] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
| | | | | | | | - Jørn Våge
- Norwegian Veterinary Institute Oslo Norway
| | | | | | - Olav Strand
- Norwegian Institute for Nature Research (NINA) Trondheim Norway
| | - Atle Mysterud
- Department of BiosciencesCentre for Ecological and Evolutionary Synthesis (CEES)University of Oslo Oslo Norway
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20
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Cross PC, van Manen FT, Viana M, Almberg ES, Bachen D, Brandell EE, Haroldson MA, Hudson PJ, Stahler DR, Smith DW. Estimating distemper virus dynamics among wolves and grizzly bears using serology and Bayesian state-space models. Ecol Evol 2018; 8:8726-8735. [PMID: 30271540 PMCID: PMC6157674 DOI: 10.1002/ece3.4396] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/08/2018] [Accepted: 06/27/2018] [Indexed: 02/05/2023] Open
Abstract
Many parasites infect multiple hosts, but estimating the transmission across host species remains a key challenge in disease ecology. We investigated the within and across host species dynamics of canine distemper virus (CDV) in grizzly bears (Ursus arctos) and wolves (Canis lupus) of the Greater Yellowstone Ecosystem (GYE). We hypothesized that grizzly bears may be more likely to be exposed to CDV during outbreaks in the wolf population because grizzly bears often displace wolves while scavenging carcasses. We used serological data collected from 1984 to 2014 in conjunction with Bayesian state-space models to infer the temporal dynamics of CDV. These models accounted for the unknown timing of pathogen exposure, and we assessed how different testing thresholds and the potential for testing errors affected our conclusions. We identified three main CDV outbreaks (1999, 2005, and 2008) in wolves, which were more obvious when we used higher diagnostic thresholds to qualify as seropositive. There was some evidence for increased exposure rates in grizzly bears in 2005, but the magnitude of the wolf effect on bear exposures was poorly estimated and depended upon our prior distributions. Grizzly bears were exposed to CDV prior to wolf reintroduction and during time periods outside of known wolf outbreaks, thus wolves are only one of several potential routes for grizzly bear exposures. Our modeling approach accounts for several of the shortcomings of serological data and is applicable to many wildlife disease systems, but is most informative when testing intervals are short. CDV circulates in a wide range of carnivore species, but it remains unclear whether the disease persists locally within the GYE carnivore community or is periodically reintroduced from distant regions with larger host populations.
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Affiliation(s)
- Paul C. Cross
- U.S. Geological SurveyNorthern Rocky Mountain Science CenterBozemanMontana
| | - Frank T. van Manen
- U.S. Geological SurveyNorthern Rocky Mountain Science CenterBozemanMontana
| | - Mafalda Viana
- Boyd Orr Centre for Population and Ecosystem HealthInstitute of Biodiversity, Animal Health and Comparative MedicineCollege of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | | | | | - Ellen E. Brandell
- Department of BiologyHuck Institutes of the Life SciencesPennsylvania State UniversityUniversity ParkPennsylvania
| | - Mark A. Haroldson
- U.S. Geological SurveyNorthern Rocky Mountain Science CenterBozemanMontana
| | - Peter J. Hudson
- Department of BiologyHuck Institutes of the Life SciencesPennsylvania State UniversityUniversity ParkPennsylvania
| | - Daniel R. Stahler
- Yellowstone Wolf ProjectYellowstone National Park, National Park ServiceGardinerWyoming
| | - Douglas W. Smith
- Yellowstone Wolf ProjectYellowstone National Park, National Park ServiceGardinerWyoming
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21
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Jennelle CS, Walsh DP, Samuel MD, Osnas EE, Rolley R, Langenberg J, Powers JG, Monello RJ, Demarest ED, Gubler R, Heisey DM. Applying a Bayesian weighted surveillance approach to detect chronic wasting disease in white‐tailed deer. J Appl Ecol 2018. [DOI: 10.1111/1365-2664.13178] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | - Daniel P. Walsh
- US Geological SurveyNational Wildlife Health Centre Madison Wisconsin
| | - Michael D. Samuel
- US Geological SurveyWisconsin Cooperative Wildlife Research UnitUniversity of Wisconsin Madison Wisconsin
| | - Erik E. Osnas
- US Fish and Wildlife ServiceDivision of Migratory Bird Management Anchorage Alaska
| | - Robert Rolley
- Wisconsin Department of Natural Resources Madison Wisconsin
| | | | - Jenny G. Powers
- Biological Resources DivisionNational Park Service Fort Collins Colorado
| | - Ryan J. Monello
- Biological Resources DivisionNational Park Service Fort Collins Colorado
| | | | | | - Dennis M. Heisey
- US Geological SurveyNational Wildlife Health Centre Madison Wisconsin
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22
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Ferguson PF, Breyta R, Brito I, Kurath G, LaDeau SL. An epidemiological model of virus transmission in salmonid fishes of the Columbia River Basin. Ecol Modell 2018. [DOI: 10.1016/j.ecolmodel.2018.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Russell RE, Katz RA, Richgels KLD, Walsh DP, Grant EHC. A Framework for Modeling Emerging Diseases to Inform Management. Emerg Infect Dis 2018; 23:1-6. [PMID: 27983501 PMCID: PMC5176225 DOI: 10.3201/eid2301.161452] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The rapid emergence and reemergence of zoonotic diseases requires the ability to rapidly evaluate and implement optimal management decisions. Actions to control or mitigate the effects of emerging pathogens are commonly delayed because of uncertainty in the estimates and the predicted outcomes of the control tactics. The development of models that describe the best-known information regarding the disease system at the early stages of disease emergence is an essential step for optimal decision-making. Models can predict the potential effects of the pathogen, provide guidance for assessing the likelihood of success of different proposed management actions, quantify the uncertainty surrounding the choice of the optimal decision, and highlight critical areas for immediate research. We demonstrate how to develop models that can be used as a part of a decision-making framework to determine the likelihood of success of different management actions given current knowledge.
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24
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Warbington CH, Van Deelen TR, Norton AS, Stenglein JL, Storm DJ, Martin KJ. Cause-specific neonatal mortality of white-tailed deer in Wisconsin, USA. J Wildl Manage 2017. [DOI: 10.1002/jwmg.21260] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | | | - Andrew S. Norton
- University of Wisconsin-Madison; 1630 Linden Drive Madison WI 53706 USA
| | | | - Daniel J. Storm
- Wisconsin Department of Natural Resources; 107 Sutliff Avenue Rhinelander WI 54501 USA
| | - Karl J. Martin
- Wisconsin Department of Natural Resources; 2801 Progress Road Madison WI 53716 USA
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25
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Pacifici K, Reich BJ, Miller DAW, Gardner B, Stauffer G, Singh S, McKerrow A, Collazo JA. Integrating multiple data sources in species distribution modeling: a framework for data fusion*. Ecology 2017; 98:840-850. [DOI: 10.1002/ecy.1710] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 12/05/2016] [Accepted: 12/14/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Krishna Pacifici
- Department of Forestry and Environmental Resources; Program in Fisheries, Wildlife, and Conservation Biology; North Carolina State University; Raleigh North Carolina 27695 USA
| | - Brian J. Reich
- Department of Statistics; North Carolina State University; Raleigh North Carolina 27695 USA
| | - David A. W. Miller
- Department of Ecosystem Science and Management; Pennsylvania State University; University Park Pennsylvania 16802 USA
| | - Beth Gardner
- School of Environmental and Forest Sciences; University of Washington; Seattle Washington 98195 USA
| | - Glenn Stauffer
- Department of Ecosystem Science and Management; Pennsylvania State University; University Park Pennsylvania 16802 USA
| | - Susheela Singh
- Department of Statistics; North Carolina State University; Raleigh North Carolina 27695 USA
| | - Alexa McKerrow
- U.S. Geological Survey; Core Science Systems, Biodiversity and Spatial Information Center; North Carolina State University; Raleigh North Carolina 27695 USA
| | - Jaime A. Collazo
- U.S. Geological Survey; North Carolina Cooperative Fish and Wildlife Research Unit; Department of Applied Ecology; North Carolina State University; Raleigh North Carolina 27695 USA
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26
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Pepin KM, Kay SL, Golas BD, Shriner SS, Gilbert AT, Miller RS, Graham AL, Riley S, Cross PC, Samuel MD, Hooten MB, Hoeting JA, Lloyd‐Smith JO, Webb CT, Buhnerkempe MG. Inferring infection hazard in wildlife populations by linking data across individual and population scales. Ecol Lett 2017; 20:275-292. [PMID: 28090753 PMCID: PMC7163542 DOI: 10.1111/ele.12732] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/28/2016] [Accepted: 12/15/2016] [Indexed: 12/11/2022]
Abstract
Our ability to infer unobservable disease-dynamic processes such as force of infection (infection hazard for susceptible hosts) has transformed our understanding of disease transmission mechanisms and capacity to predict disease dynamics. Conventional methods for inferring FOI estimate a time-averaged value and are based on population-level processes. Because many pathogens exhibit epidemic cycling and FOI is the result of processes acting across the scales of individuals and populations, a flexible framework that extends to epidemic dynamics and links within-host processes to FOI is needed. Specifically, within-host antibody kinetics in wildlife hosts can be short-lived and produce patterns that are repeatable across individuals, suggesting individual-level antibody concentrations could be used to infer time since infection and hence FOI. Using simulations and case studies (influenza A in lesser snow geese and Yersinia pestis in coyotes), we argue that with careful experimental and surveillance design, the population-level FOI signal can be recovered from individual-level antibody kinetics, despite substantial individual-level variation. In addition to improving inference, the cross-scale quantitative antibody approach we describe can reveal insights into drivers of individual-based variation in disease response, and the role of poorly understood processes such as secondary infections, in population-level dynamics of disease.
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Affiliation(s)
- Kim M. Pepin
- National Wildlife Research CenterUnited States Department of Agriculture4101 Laporte Ave.Fort CollinsCO80521USA
| | - Shannon L. Kay
- National Wildlife Research CenterUnited States Department of Agriculture4101 Laporte Ave.Fort CollinsCO80521USA
| | - Ben D. Golas
- Department of BiologyColorado State UniversityFort CollinsCO80523USA
| | - Susan S. Shriner
- National Wildlife Research CenterUnited States Department of Agriculture4101 Laporte Ave.Fort CollinsCO80521USA
| | - Amy T. Gilbert
- National Wildlife Research CenterUnited States Department of Agriculture4101 Laporte Ave.Fort CollinsCO80521USA
| | - Ryan S. Miller
- Animal and Plant Health Inspection ServiceUnited States Department of AgricultureVeterinary Services2155 Center DriveBuilding BFort CollinsCO80523USA
| | - Andrea L. Graham
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNJ08544USA
| | - Steven Riley
- MRC Centre for Outbreak Analysis and ModellingImperial CollegeLondonUK
| | - Paul C. Cross
- U.S. Geological SurveyNorthern Rocky Mountain Science Center2327 University WayBozemanMT59715USA
| | - Michael D. Samuel
- U. S. Geological SurveyWisconsin Cooperative Wildlife Research Unit1630 Linden DroveUniversity of WisconsinMadisonWI53706USA
| | - Mevin B. Hooten
- U.S. Geological SurveyColorado Cooperative Fish and Wildlife Research Unit; Departments of FishWildlife& Conservation Biology and StatisticsColorado State University1484 Campus DeliveryFort CollinsCO80523USA
| | | | | | - Colleen T. Webb
- Department of BiologyColorado State UniversityFort CollinsCO80523USA
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27
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Hurley MA, Hebblewhite M, Lukacs PM, Nowak JJ, Gaillard JM, Bonenfant C. Regional-scale models for predicting overwinter survival of juvenile ungulates. J Wildl Manage 2017. [DOI: 10.1002/jwmg.21211] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Mark A. Hurley
- Idaho Department of Fish and Game; 600 South Walnut Street; Boise ID 83712 USA
| | - Mark Hebblewhite
- Wildlife Biology Program; Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and Conservation, University of Montana; Missoula MT 59812 USA
| | - Paul M. Lukacs
- Wildlife Biology Program; Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and Conservation, University of Montana; Missoula MT 59812 USA
| | - J. Joshua Nowak
- Wildlife Biology Program; W.A. Franke College of Forestry and Conservation; University of Montana; Missoula MT 59812 USA
| | - Jean-Michel Gaillard
- Laboratoire Biométrie et Biologie Évolutive; UMR-CNRS 5558, University Claude Bernard − Lyon I; 69622 Villeurbanne Cedex France
| | - Christophe Bonenfant
- Laboratoire Biométrie et Biologie Évolutive; UMR-CNRS 5558, University Claude Bernard − Lyon I; 69622 Villeurbanne Cedex France
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28
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Modeled Impacts of Chronic Wasting Disease on White-Tailed Deer in a Semi-Arid Environment. PLoS One 2016; 11:e0163592. [PMID: 27711208 PMCID: PMC5053495 DOI: 10.1371/journal.pone.0163592] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 09/12/2016] [Indexed: 12/21/2022] Open
Abstract
White-tailed deer are a culturally and economically important game species in North America, especially in South Texas. The recent discovery of chronic wasting disease (CWD) in captive deer facilities in Texas has increased concern about the potential emergence of CWD in free-ranging deer. The concern is exacerbated because much of the South Texas region is a semi-arid environment with variable rainfall, where precipitation is strongly correlated with fawn recruitment. Further, the marginally productive rangelands, in combination with erratic fawn recruitment, results in populations that are frequently density-independent, and thus sensitive to additive mortality. It is unknown how a deer population in semi-arid regions would respond to the presence of CWD. We used long-term empirical datasets from a lightly harvested (2% annual harvest) population in conjunction with 3 prevalence growth rates from CWD afflicted areas (0.26%, 0.83%, and 2.3% increases per year) via a multi-stage partially deterministic model to simulate a deer population for 25 years under four scenarios: 1) without CWD and without harvest, 2) with CWD and without harvest, 3) with CWD and male harvest only, and 4) with CWD and harvest of both sexes. The modeled populations without CWD and without harvest averaged a 1.43% annual increase over 25 years; incorporation of 2% annual harvest of both sexes resulted in a stable population. The model with slowest CWD prevalence rate growth (0.26% annually) without harvest resulted in stable populations but the addition of 1% harvest resulted in population declines. Further, the male age structure in CWD models became skewed to younger age classes. We incorporated fawn:doe ratios from three CWD afflicted areas in Wisconsin and Wyoming into the model with 0.26% annual increase in prevalence and populations did not begin to decline until ~10%, ~16%, and ~26% of deer were harvested annually. Deer populations in variable environments rely on high adult survivorship to buffer the low and erratic fawn recruitment rates. The increase in additive mortality rates for adults via CWD negatively impacted simulated population trends to the extent that hunter opportunity would be greatly reduced. Our results improve understanding of the potential influences of CWD on deer populations in semi-arid environments with implications for deer managers, disease ecologists, and policy makers.
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29
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Samuel MD, Storm DJ. Chronic wasting disease in white-tailed deer: infection, mortality, and implications for heterogeneous transmission. Ecology 2016; 97:3195-3205. [PMID: 27870037 DOI: 10.1002/ecy.1538] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/29/2016] [Accepted: 07/05/2016] [Indexed: 11/08/2022]
Abstract
Chronic wasting disease (CWD) is a fatal neurodegenerative disease affecting free-ranging and captive cervids that now occurs in 24 U.S. states and two Canadian provinces. Despite the potential threat of CWD to deer populations, little is known about the rates of infection and mortality caused by this disease. We used epidemiological models to estimate the force of infection and disease-associated mortality for white-tailed deer in the Wisconsin and Illinois CWD outbreaks. Models were based on age-prevalence data corrected for bias in aging deer using the tooth wear and replacement method. Both male and female deer in the Illinois outbreak had higher corrected age-specific prevalence with slightly higher female infection than deer in the Wisconsin outbreak. Corrected ages produced more complex models with different infection and mortality parameters than those based on apparent prevalence. We found that adult male deer have a more than threefold higher risk of CWD infection than female deer. Males also had higher disease mortality than female deer. As a result, CWD prevalence was twofold higher in adult males than females. We also evaluated the potential impacts of alternative contact structures on transmission dynamics in Wisconsin deer. Results suggested that transmission of CWD among male deer during the nonbreeding season may be a potential mechanism for producing higher rates of infection and prevalence characteristically found in males. However, alternatives based on high environmental transmission and transmission from females to males during the breeding season may also play a role.
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Affiliation(s)
- Michael D Samuel
- U.S. Geological Survey, Wisconsin Cooperative Wildlife Research Unit, University of Wisconsin , Madison, Wisconsin, 53706, USA
| | - Daniel J Storm
- Department of Forest and Wildlife Ecology, University of Wisconsin , Madison, Wisconsin, 53706, USA.,Wisconsin Department of Natural Resources, Rhinelander, Wisconsin, 54501, USA
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30
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Nobert BR, Merrill EH, Pybus MJ, Bollinger TK, Hwang YT. Landscape connectivity predicts chronic wasting disease risk in Canada. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12677] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Barry R. Nobert
- Department of Biological Sciences; University of Alberta; Edmonton AB T6G 2E9 Canada
| | - Evelyn H. Merrill
- Department of Biological Sciences; University of Alberta; Edmonton AB T6G 2E9 Canada
| | - Margo J. Pybus
- Department of Biological Sciences; University of Alberta; Edmonton AB T6G 2E9 Canada
- Alberta Fish and Wildlife Division; Government of Alberta; Edmonton AB T6H 4P2 Canada
| | - Trent K. Bollinger
- Canadian Cooperative Wildlife Health Centre; Western College of Veterinary Medicine; University of Saskatchewan; Saskatoon SK S7N 5B4 Canada
| | - Yeen Ten Hwang
- Saskatchewan Ministry of Environment; Government of Saskatchewan; Regina SK S4S 5W6 Canada
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31
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Potapov A, Merrill E, Pybus M, Lewis MA. Chronic Wasting Disease: Transmission Mechanisms and the Possibility of Harvest Management. PLoS One 2016; 11:e0151039. [PMID: 26963921 PMCID: PMC4786122 DOI: 10.1371/journal.pone.0151039] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 02/23/2016] [Indexed: 01/30/2023] Open
Abstract
We develop a model of CWD management by nonselective deer harvest, currently the most feasible approach available for managing CWD in wild populations. We use the model to explore the effects of 6 common harvest strategies on disease prevalence and to identify potential optimal harvest policies for reducing disease prevalence without population collapse. The model includes 4 deer categories (juveniles, adult females, younger adult males, older adult males) that may be harvested at different rates, a food-based carrying capacity, which influences juvenile survival but not adult reproduction or survival, and seasonal force of infection terms for each deer category under differing frequency-dependent transmission dynamics resulting from environmental and direct contact mechanisms. Numerical experiments show that the interval of transmission coefficients β where the disease can be controlled is generally narrow and efficiency of a harvest policy to reduce disease prevalence depends crucially on the details of the disease transmission mechanism, in particular on the intensity of disease transmission to juveniles and the potential differences in the behavior of older and younger males that influence contact rates. Optimal harvest policy to minimize disease prevalence for each of the assumed transmission mechanisms is shown to depend on harvest intensity. Across mechanisms, a harvest that focuses on antlered deer, without distinguishing between age classes reduces disease prevalence most consistently, whereas distinguishing between young and older antlered deer produces higher uncertainty in the harvest effects on disease prevalence. Our results show that, despite uncertainties, a modelling approach can determine classes of harvest strategy that are most likely to be effective in combatting CWD.
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Affiliation(s)
- Alex Potapov
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Centre for Mathematical Biology, University of Alberta, Edmonton, Alberta, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
| | - Evelyn Merrill
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Margo Pybus
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Alberta Sustainable Resource Development, Edmonton, Alberta, Canada
| | - Mark A. Lewis
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Centre for Mathematical Biology, University of Alberta, Edmonton, Alberta, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada
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Geremia C, Miller MW, Hoeting JA, Antolin MF, Hobbs NT. Bayesian Modeling of Prion Disease Dynamics in Mule Deer Using Population Monitoring and Capture-Recapture Data. PLoS One 2015; 10:e0140687. [PMID: 26509806 PMCID: PMC4624844 DOI: 10.1371/journal.pone.0140687] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/28/2015] [Indexed: 12/30/2022] Open
Abstract
Epidemics of chronic wasting disease (CWD) of North American Cervidae have potential to harm ecosystems and economies. We studied a migratory population of mule deer (Odocoileus hemionus) affected by CWD for at least three decades using a Bayesian framework to integrate matrix population and disease models with long-term monitoring data and detailed process-level studies. We hypothesized CWD prevalence would be stable or increase between two observation periods during the late 1990s and after 2010, with higher CWD prevalence making deer population decline more likely. The weight of evidence suggested a reduction in the CWD outbreak over time, perhaps in response to intervening harvest-mediated population reductions. Disease effects on deer population growth under current conditions were subtle with a 72% chance that CWD depressed population growth. With CWD, we forecasted a growth rate near one and largely stable deer population. Disease effects appear to be moderated by timing of infection, prolonged disease course, and locally variable infection. Long-term outcomes will depend heavily on whether current conditions hold and high prevalence remains a localized phenomenon.
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Affiliation(s)
- Chris Geremia
- Natural Resource Ecology Laboratory, Department of Ecosystem Science and Sustainability and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Michael W. Miller
- Wildlife Health Program, Colorado Division of Parks and Wildlife, Fort Collins, Colorado, Colorado, United States of America
| | - Jennifer A. Hoeting
- Department of Statistics, Colorado State University, Fort Collins, Colorado, United States of America
| | - Michael F. Antolin
- Department of Biology, Colorado State University, Fort Collins, Colorado, United States of America
| | - N. Thompson Hobbs
- Natural Resource Ecology Laboratory, Department of Ecosystem Science and Sustainability and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, United States of America
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Abstract
Modelling wildlife disease poses some unique challenges. Wildlife disease systems are data poor in comparison with human or livestock disease systems, and the impact of disease on population size is often the key question of interest. This review concentrates specifically on the application of dynamic models to evaluate and guide management strategies. Models have proved useful particularly in two areas. They have been widely used to evaluate vaccination strategies, both for protecting endangered species and for preventing spillover from wildlife to humans or livestock. They have also been extensively used to evaluate culling strategies, again both for diseases in species of conservation interest and to prevent spillover. In addition, models are important to evaluate the potential of parasites and pathogens as biological control agents. The review concludes by identifying some key research gaps, which are further development of models of macroparasites, deciding on appropriate levels of complexity, modelling genetic management and connecting models to data.
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Cross PC, Maichak EJ, Rogerson JD, Irvine KM, Jones JD, Heisey DM, Edwards WH, Scurlock BM. Estimating the phenology of elk brucellosis transmission with hierarchical models of cause-specific and baseline hazards. J Wildl Manage 2015. [DOI: 10.1002/jwmg.883] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Paul C. Cross
- U.S. Geological Survey; Northern Rocky Mountain Science Center; Bozeman MT 59715 USA
| | | | | | - Kathryn M. Irvine
- U.S. Geological Survey; Northern Rocky Mountain Science Center; Bozeman MT 59715 USA
| | - Jennifer D. Jones
- Institute on Ecosystems; Montana State University; Bozeman MT 59715 USA
| | - Dennis M. Heisey
- U.S. Geological Survey; National Wildlife Health Center; Madison WI 53711 USA
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Proffitt KM, Anderson N, Lukacs P, Riordan MM, Gude JA, Shamhart J. Effects of elk density on elk aggregation patterns and exposure to brucellosis. J Wildl Manage 2015. [DOI: 10.1002/jwmg.860] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Kelly M. Proffitt
- Montana Department of Fish; Wildlife and Parks; Bozeman MT 59718 USA
| | - Neil Anderson
- Montana Department of Fish; Wildlife and Parks; Bozeman MT 59718 USA
| | - Paul Lukacs
- Department of Ecosystem and Conservation Sciences; Wildlife Biology Program; College of Forestry and Conservation; University of Montana; Missoula MT 59812 USA
| | - Margaret M. Riordan
- Montana Cooperative Wildlife Research Unit; University of Montana; Missoula MT 59812 USA
| | | | - Julee Shamhart
- Montana Department of Fish; Wildlife and Parks; Bozeman MT 59718 USA
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36
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Walsh DP, Dreitz VJ, Heisey DM. Integrated survival analysis using an event-time approach in a Bayesian framework. Ecol Evol 2015; 5:769-80. [PMID: 25691997 PMCID: PMC4328778 DOI: 10.1002/ece3.1399] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/16/2014] [Accepted: 12/18/2014] [Indexed: 11/11/2022] Open
Abstract
Event-time or continuous-time statistical approaches have been applied throughout the biostatistical literature and have led to numerous scientific advances. However, these techniques have traditionally relied on knowing failure times. This has limited application of these analyses, particularly, within the ecological field where fates of marked animals may be unknown. To address these limitations, we developed an integrated approach within a Bayesian framework to estimate hazard rates in the face of unknown fates. We combine failure/survival times from individuals whose fates are known and times of which are interval-censored with information from those whose fates are unknown, and model the process of detecting animals with unknown fates. This provides the foundation for our integrated model and permits necessary parameter estimation. We provide the Bayesian model, its derivation, and use simulation techniques to investigate the properties and performance of our approach under several scenarios. Lastly, we apply our estimation technique using a piece-wise constant hazard function to investigate the effects of year, age, chick size and sex, sex of the tending adult, and nesting habitat on mortality hazard rates of the endangered mountain plover (Charadrius montanus) chicks. Traditional models were inappropriate for this analysis because fates of some individual chicks were unknown due to failed radio transmitters. Simulations revealed biases of posterior mean estimates were minimal (≤ 4.95%), and posterior distributions behaved as expected with RMSE of the estimates decreasing as sample sizes, detection probability, and survival increased. We determined mortality hazard rates for plover chicks were highest at <5 days old and were lower for chicks with larger birth weights and/or whose nest was within agricultural habitats. Based on its performance, our approach greatly expands the range of problems for which event-time analyses can be used by eliminating the need for having completely known fate data.
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Affiliation(s)
- Daniel P Walsh
- National Wildlife Health Center, United States Geological Survey 6006 Schroeder Road, Madison, Wisconsin, 53711
| | - Victoria J Dreitz
- Wildlife Biology Program and Avian Science Center, College of Forestry and Conservation, University of Montana Montana, 59812
| | - Dennis M Heisey
- National Wildlife Health Center, United States Geological Survey 6006 Schroeder Road, Madison, Wisconsin, 53711
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Storm DJ, Samuel MD, Rolley RE, Beissel T, Richards BJ, Van Deelen TR. Estimating ages of white-tailed deer: Age and sex patterns of error using tooth wear-and-replacement and consistency of cementum annuli. WILDLIFE SOC B 2014. [DOI: 10.1002/wsb.457] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Daniel J. Storm
- Department of Forest and Wildlife Ecology; University of Wisconsin-Madison; 226 Russell Labs 1630 Linden Drive Madison WI 53706 USA
| | - Michael D. Samuel
- United States Geological Survey; Wisconsin Cooperative Wildlife Research Unit; Department of Forest and Wildlife Ecology; University of Wisconsin-Madison; 204 Russell Labs 1630 Linden Drive Madison Wisconsin 53706 USA
| | - Robert E. Rolley
- Bureau of Science Services; Wisconsin Department of Natural Resources; 2801 Progress Road Madison WI 53716 USA
| | - Thomas Beissel
- Illinois Department of Natural Resources; 1 Natural Resources Way Springfield IL 62702 USA
| | - Bryan J. Richards
- Unites States Geological Survey; National Wildlife Health Center; 6006 Schroeder Road Madison WI 53711 USA
| | - Timothy R. Van Deelen
- Department of Forest and Wildlife Ecology; University of Wisconsin-Madison; 226 Russell Labs 1630 Linden Drive Madison WI 53706 USA
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Assembling evidence for identifying reservoirs of infection. Trends Ecol Evol 2014; 29:270-9. [PMID: 24726345 PMCID: PMC4007595 DOI: 10.1016/j.tree.2014.03.002] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 03/03/2014] [Accepted: 03/10/2014] [Indexed: 12/25/2022]
Abstract
We review the problem of identifying reservoirs of infection for multihost pathogens and provide an overview of current approaches and future directions. We provide a conceptual framework for classifying patterns of incidence and prevalence. We review current methods that allow us to characterise the components of reservoir-target systems. Ecological theory offers promising new ways to prioritise populations when designing interventions. We propose using interventions as quasi-experiments embedded in adaptive management frameworks. Integration of data and analysis provides powerful new opportunities for studying multihost systems.
Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in enriching our mechanistic understanding of how reservoirs function and should be embedded as quasi-experimental studies in adaptive management frameworks. Single approaches to the study of reservoirs are unlikely to generate conclusive insights whereas the formal integration of data and methodologies, involving interventions, pathogen genetics, and contemporary surveillance techniques, promises to open up new opportunities to advance understanding of complex multihost systems.
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Jennelle CS, Henaux V, Wasserberg G, Thiagarajan B, Rolley RE, Samuel MD. Transmission of chronic wasting disease in Wisconsin white-tailed deer: implications for disease spread and management. PLoS One 2014; 9:e91043. [PMID: 24658535 PMCID: PMC3962341 DOI: 10.1371/journal.pone.0091043] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 02/07/2014] [Indexed: 11/27/2022] Open
Abstract
Few studies have evaluated the rate of infection or mode of transmission for wildlife diseases, and the implications of alternative management strategies. We used hunter harvest data from 2002 to 2013 to investigate chronic wasting disease (CWD) infection rate and transmission modes, and address how alternative management approaches affect disease dynamics in a Wisconsin white-tailed deer population. Uncertainty regarding demographic impacts of CWD on cervid populations, human and domestic animal health concerns, and potential economic consequences underscore the need for strategies to control CWD distribution and prevalence. Using maximum-likelihood methods to evaluate alternative multi-state deterministic models of CWD transmission, harvest data strongly supports a frequency-dependent transmission structure with sex-specific infection rates that are two times higher in males than females. As transmissible spongiform encephalopathies are an important and difficult-to-study class of diseases with major economic and ecological implications, our work supports the hypothesis of frequency-dependent transmission in wild deer at a broad spatial scale and indicates that effective harvest management can be implemented to control CWD prevalence. Specifically, we show that harvest focused on the greater-affected sex (males) can result in stable population dynamics and control of CWD within the next 50 years, given the constraints of the model. We also provide a quantitative estimate of geographic disease spread in southern Wisconsin, validating qualitative assessments that CWD spreads relatively slowly. Given increased discovery and distribution of CWD throughout North America, insights from our study are valuable to management agencies and to the general public concerned about the impacts of CWD on white-tailed deer populations.
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Affiliation(s)
- Christopher S. Jennelle
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Viviane Henaux
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Gideon Wasserberg
- Biology Department, University of North Carolina, Greensboro, North Carolina, United States of America
| | - Bala Thiagarajan
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Robert E. Rolley
- Wisconsin Department of Natural Resources, Madison, Wisconsin, United States of America
| | - Michael D. Samuel
- U.S. Geological Survey, Wisconsin Cooperative Wildlife Research Unit, University of Wisconsin, Madison, Wisconsin, United States of America
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40
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Gilbert AT, Fooks AR, Hayman DTS, Horton DL, Müller T, Plowright R, Peel AJ, Bowen R, Wood JLN, Mills J, Cunningham AA, Rupprecht CE. Deciphering serology to understand the ecology of infectious diseases in wildlife. ECOHEALTH 2013; 10:298-313. [PMID: 23918033 DOI: 10.1007/s10393-013-0856-0] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/03/2013] [Accepted: 06/04/2013] [Indexed: 06/02/2023]
Abstract
The ecology of infectious disease in wildlife has become a pivotal theme in animal and public health. Studies of infectious disease ecology rely on robust surveillance of pathogens in reservoir hosts, often based on serology, which is the detection of specific antibodies in the blood and is used to infer infection history. However, serological data can be inaccurate for inference to infection history for a variety of reasons. Two major aspects in any serological test can substantially impact results and interpretation of antibody prevalence data: cross-reactivity and cut-off thresholds used to discriminate positive and negative reactions. Given the ubiquitous use of serology as a tool for surveillance and epidemiological modeling of wildlife diseases, it is imperative to consider the strengths and limitations of serological test methodologies and interpretation of results, particularly when using data that may affect management and policy for the prevention and control of infectious diseases in wildlife. Greater consideration of population age structure and cohort representation, serological test suitability and standardized sample collection protocols can ensure that reliable data are obtained for downstream modeling applications to characterize, and evaluate interventions for, wildlife disease systems.
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Affiliation(s)
- Amy T Gilbert
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA,
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Joseph MB, Mihaljevic JR, Arellano AL, Kueneman JG, Preston DL, Cross PC, Johnson PTJ. Taming wildlife disease: bridging the gap between science and management. J Appl Ecol 2013; 50:702-712. [PMID: 32336775 PMCID: PMC7166616 DOI: 10.1111/1365-2664.12084] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 03/04/2013] [Indexed: 01/16/2023]
Abstract
Parasites and pathogens of wildlife can threaten biodiversity, infect humans and domestic animals, and cause significant economic losses, providing incentives to manage wildlife diseases. Recent insights from disease ecology have helped transform our understanding of infectious disease dynamics and yielded new strategies to better manage wildlife diseases. Simultaneously, wildlife disease management (WDM) presents opportunities for large‐scale empirical tests of disease ecology theory in diverse natural systems. To assess whether the potential complementarity between WDM and disease ecology theory has been realized, we evaluate the extent to which specific concepts in disease ecology theory have been explicitly applied in peer‐reviewed WDM literature. While only half of WDM articles published in the past decade incorporated disease ecology theory, theory has been incorporated with increasing frequency over the past 40 years. Contrary to expectations, articles authored by academics were no more likely to apply disease ecology theory, but articles that explain unsuccessful management often do so in terms of theory. Some theoretical concepts such as density‐dependent transmission have been commonly applied, whereas emerging concepts such as pathogen evolutionary responses to management, biodiversity–disease relationships and within‐host parasite interactions have not yet been fully integrated as management considerations. Synthesis and applications. Theory‐based disease management can meet the needs of both academics and managers by testing disease ecology theory and improving disease interventions. Theoretical concepts that have received limited attention to date in wildlife disease management could provide a basis for improving management and advancing disease ecology in the future.
Theory‐based disease management can meet the needs of both academics and managers by testing disease ecology theory and improving disease interventions. Theoretical concepts that have received limited attention to date in wildlife disease management could provide a basis for improving management and advancing disease ecology in the future.
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Affiliation(s)
- Maxwell B Joseph
- Department of Ecology and Evolutionary Biology University of Colorado CB 334 Boulder CO 80309 USA
| | - Joseph R Mihaljevic
- Department of Ecology and Evolutionary Biology University of Colorado CB 334 Boulder CO 80309 USA
| | - Ana Lisette Arellano
- Department of Ecology and Evolutionary Biology University of Colorado CB 334 Boulder CO 80309 USA
| | - Jordan G Kueneman
- Department of Ecology and Evolutionary Biology University of Colorado CB 334 Boulder CO 80309 USA
| | - Daniel L Preston
- Department of Ecology and Evolutionary Biology University of Colorado CB 334 Boulder CO 80309 USA
| | - Paul C Cross
- Northern Rocky Mountain Science Center U. S. Geological Survey 2327 University Way, Suite 2 Bozeman MT 59715 USA
| | - Pieter T J Johnson
- Department of Ecology and Evolutionary Biology University of Colorado CB 334 Boulder CO 80309 USA
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42
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Cassirer EF, Plowright RK, Manlove KR, Cross PC, Dobson AP, Potter KA, Hudson PJ. Spatio-temporal dynamics of pneumonia in bighorn sheep. J Anim Ecol 2013; 82:518-28. [PMID: 23398603 DOI: 10.1111/1365-2656.12031] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 10/31/2012] [Indexed: 12/01/2022]
Abstract
1. Bighorn sheep mortality related to pneumonia is a primary factor limiting population recovery across western North America, but management has been constrained by an incomplete understanding of the disease. We analysed patterns of pneumonia-caused mortality over 14 years in 16 interconnected bighorn sheep populations to gain insights into underlying disease processes. 2. We observed four age-structured classes of annual pneumonia mortality patterns: all-age, lamb-only, secondary all-age and adult-only. Although there was considerable variability within classes, overall they differed in persistence within and impact on populations. Years with pneumonia-induced mortality occurring simultaneously across age classes (i.e. all-age) appeared to be a consequence of pathogen invasion into a naïve population and resulted in immediate population declines. Subsequently, low recruitment due to frequent high mortality outbreaks in lambs, probably due to association with chronically infected ewes, posed a significant obstacle to population recovery. Secondary all-age events occurred in previously exposed populations when outbreaks in lambs were followed by lower rates of pneumonia-induced mortality in adults. Infrequent pneumonia events restricted to adults were usually of short duration with low mortality. 3. Acute pneumonia-induced mortality in adults was concentrated in fall and early winter around the breeding season when rams are more mobile and the sexes commingle. In contrast, mortality restricted to lambs peaked in summer when ewes and lambs were concentrated in nursery groups. 4. We detected weak synchrony in adult pneumonia between adjacent populations, but found no evidence for landscape-scale extrinsic variables as drivers of disease. 5. We demonstrate that there was a >60% probability of a disease event each year following pneumonia invasion into bighorn sheep populations. Healthy years also occurred periodically, and understanding the factors driving these apparent fade-out events may be the key to managing this disease. Our data and modelling indicate that pneumonia can have greater impacts on bighorn sheep populations than previously reported, and we present hypotheses about processes involved for testing in future investigations and management.
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Affiliation(s)
- E Frances Cassirer
- Idaho Department of Fish and Game, 3316 16th St., Lewiston, ID, 83501, USA
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43
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44
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Storm DJ, Samuel MD, Rolley RE, Shelton P, Keuler NS, Richards BJ, Van Deelen TR. Deer density and disease prevalence influence transmission of chronic wasting disease in white-tailed deer. Ecosphere 2013. [DOI: 10.1890/es12-00141.1] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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45
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Potapov A, Merrill E, Lewis MA. Wildlife disease elimination and density dependence. Proc Biol Sci 2012; 279:3139-45. [PMID: 22593103 DOI: 10.1098/rspb.2012.0520] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Disease control by managers is a crucial response to emerging wildlife epidemics, yet the means of control may be limited by the method of disease transmission. In particular, it is widely held that population reduction, while effective for controlling diseases that are subject to density-dependent (DD) transmission, is ineffective for controlling diseases that are subject to frequency-dependent (FD) transmission. We investigate control for horizontally transmitted diseases with FD transmission where the control is via culling or harvest that is non-selective with respect to infection and the population can compensate through DD recruitment or survival. Using a mathematical model, we show that culling or harvesting can eradicate the disease, even when transmission dynamics are FD. Eradication can be achieved under FD transmission when DD birth or recruitment induces compensatory growth of new, healthy individuals, which has the net effect of reducing disease prevalence by dilution. We also show that if harvest is used simultaneously with vaccination, and there is high enough transmission coefficient, application of both controls may be less efficient than vaccination alone. We illustrate the effects of these control approaches on disease prevalence for chronic wasting disease in deer where the disease is transmitted directly among deer and through the environment.
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Affiliation(s)
- Alex Potapov
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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46
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Robinson SJ, Samuel MD, Johnson CJ, Adams M, McKenzie DI. Emerging prion disease drives host selection in a wildlife population. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2012; 22:1050-9. [PMID: 22645831 DOI: 10.1890/11-0907.1] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Infectious diseases are increasingly recognized as an important force driving population dynamics, conservation biology, and natural selection in wildlife populations. Infectious agents have been implicated in the decline of small or endangered populations and may act to constrain population size, distribution, growth rates, or migration patterns. Further, diseases may provide selective pressures that shape the genetic diversity of populations or species. Thus, understanding disease dynamics and selective pressures from pathogens is crucial to understanding population processes, managing wildlife diseases, and conserving biological diversity. There is ample evidence that variation in the prion protein gene (PRNP) impacts host susceptibility to prion diseases. Still, little is known about how genetic differences might influence natural selection within wildlife populations. Here we link genetic variation with differential susceptibility of white-tailed deer to chronic wasting disease (CWD), with implications for fitness and disease-driven genetic selection. We developed a single nucleotide polymorphism (SNP) assay to efficiently genotype deer at the locus of interest (in the 96th codon of the PRNP gene). Then, using a Bayesian modeling approach, we found that the more susceptible genotype had over four times greater risk of CWD infection; and, once infected, deer with the resistant genotype survived 49% longer (8.25 more months). We used these epidemiological parameters in a multi-stage population matrix model to evaluate relative fitness based on genotype-specific population growth rates. The differences in disease infection and mortality rates allowed genetically resistant deer to achieve higher population growth and obtain a long-term fitness advantage, which translated into a selection coefficient of over 1% favoring the CWD-resistant genotype. This selective pressure suggests that the resistant allele could become dominant in the population within an evolutionarily short time frame. Our work provides a rare example of a quantifiable disease-driven selection process in a wildlife population, demonstrating the potential for infectious diseases to alter host populations. This will have direct bearing on the epidemiology, dynamics, and future trends in CWD transmission and spread. Understanding genotype-specific epidemiology will improve predictive models and inform management strategies for CWD-affected cervid populations.
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Affiliation(s)
- Stacie J Robinson
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Room 208 Russell Labs, 1630 Linden Drive, Madison, Wisconsin 53706, USA.
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47
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Halstead BJ, Wylie GD, Coates PS, Valcarcel P, Casazza ML. ‘Exciting statistics’: the rapid development and promising future of hierarchical models for population ecology. Anim Conserv 2012. [DOI: 10.1111/j.1469-1795.2012.00540.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- B. J. Halstead
- U.S. Geological Survey; Western Ecological Research Center; Dixon Field Station; Dixon; CA; USA
| | - G. D. Wylie
- U.S. Geological Survey; Western Ecological Research Center; Dixon Field Station; Dixon; CA; USA
| | - P. S. Coates
- U.S. Geological Survey; Western Ecological Research Center; Dixon Field Station; Dixon; CA; USA
| | - P. Valcarcel
- U.S. Geological Survey; Western Ecological Research Center; Dixon Field Station; Dixon; CA; USA
| | - M. L. Casazza
- U.S. Geological Survey; Western Ecological Research Center; Dixon Field Station; Dixon; CA; USA
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48
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Vander Wal E, Paquet PC, Andrés JA. Influence of landscape and social interactions on transmission of disease in a social cervid. Mol Ecol 2012; 21:1271-82. [PMID: 22289112 DOI: 10.1111/j.1365-294x.2011.05431.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mechanisms of pathogen transmission are often social behaviours. These occur at local scales and are affected by landscape-scale population structure. Host populations frequently exist in patchy and isolated environments that create a continuum of genetic and social familiarity. Such variability has an important multispatial effect on pathogen spread. We assessed elk dispersal (i.e. likelihood of interdeme pathogen transmission) through spatially explicit genetic analyses. At a landscape scale, the elk population was composed of one cluster within a southeast-to-northwest cline spanning three spatially discrete subpopulations of elk across two protected areas in Manitoba (Canada). Genetic data are consistent with spatial variability in apparent prevalence of bovine tuberculosis (TB) in elk. Given the existing population structure, between-subpopulation spread of disease because of elk dispersal is unlikely. Furthermore, to better understand the risk of spread and distribution of the TB, we used a combination of close-contact logging biotelemetry and genetic data, which highlights how social intercourse may affect pathogen transmission. Our results indicate that close-contact interaction rate and duration did not covary with genetic relatedness. Thus, direct elk-to-elk transmission of disease is unlikely to be constrained to related individuals. That social intercourse in elk is not limited to familial groups provides some evidence pathogen transmission may be density-dependent. We show that the combination of landscape-scale genetics, relatedness and local-scale social behaviours is a promising approach to understand and predict landscape-level pathogen transmission within our system and within all social ungulate systems affected by transmissible diseases.
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Affiliation(s)
- Eric Vander Wal
- Department of Biology, University of Saskatchewan112 Science Place, Saskatoon, SK, Canada.
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Rees EE, Merrill EH, Bollinger TK, Hwang YT, Pybus MJ, Coltman DW. Targeting the detection of chronic wasting disease using the hunter harvest during early phases of an outbreak in Saskatchewan, Canada. Prev Vet Med 2011; 104:149-59. [PMID: 22137503 DOI: 10.1016/j.prevetmed.2011.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 10/25/2011] [Accepted: 10/28/2011] [Indexed: 10/14/2022]
Abstract
Chronic wasting disease (CWD) is a fatal disease of North American cervids that was first detected in a wild, hunter-shot deer in Saskatchewan along the border with Alberta in Canada in 2000. Spatially explicit models for assessing factors affecting disease detection are needed to guide surveillance and control programs. Spatio-temporal patterns in CWD prevalence can be complicated by variation in individual infection probability and sampling biases. We assessed hunter harvest data of mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) during the early phases of an outbreak in Saskatchewan (i.e., 2002-2007) for targeting the detection of CWD by defining (1) where to look, and (2) how much effort to use. First, we accounted for known demographic heterogeneities in infection to model the probability, P(E), that a harvested deer was infected with CWD given characteristics of the harvest location. Second, in areas where infected deer were harvested we modelled the probability, P(D), of the hunter harvest re-detecting CWD within sample units of varying size (9-54 km(2)) given the demographics of harvested deer and time since first detection in the study area. Heterogeneities in host infection were consistent with those reported elsewhere: mule deer 3.7 times >white-tailed deer, males 1.8 times>females, and quadratically related to age in both sexes. P(E) increased with number of years since the first detection in our study area (2002) and proximity to known disease sources, and also varied with distance to the South Saskatchewan River and small creek drainages, terrain ruggedness, and extent of agriculture lands within a 3 km radius of the harvest. The majority (75%) of new CWD-positive deer from our sample were found within 20 km of infected deer harvested in the previous year, while approximately 10% were greater than 40 km. P(D) modelled at 18 km(2) was best supported, but for all scales, P(D) depended on the number of harvested deer and time since the first infected deer was harvested. Within an 18 km(2) sampling unit, there was an 80% probability of detecting a CWD-positive deer with 16 harvested deer five years after the initial infected harvest. Identifying where and how much to sample to detect CWD can improve targeted surveillance programs early in the outbreak of the disease when based on hunter harvest.
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Affiliation(s)
- Erin E Rees
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
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