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Egan ME, Gorman NT, Crews S, Eichholz MW, Skinner D, Schlichting PE, Rayl ND, Bergman EJ, Ellington EH, Bastille-Rousseau G. Estimating encounter-habitat relationships with scale-integrated resource selection functions. J Anim Ecol 2024; 93:1036-1048. [PMID: 38940070 DOI: 10.1111/1365-2656.14133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 05/27/2024] [Indexed: 06/29/2024]
Abstract
Encounters between animals occur when animals are close in space and time. Encounters are important in many ecological processes including sociality, predation and disease transmission. Despite this, there is little theory regarding the spatial distribution of encounters and no formal framework to relate environmental characteristics to encounters. The probability of encounter could be estimated with resource selection functions (RSFs) by comparing locations where encounters occurred to available locations where they may have occurred, but this estimate is complicated by the hierarchical nature of habitat selection. We developed a method to relate resources to the relative probability of encounter based on a scale-integrated habitat selection framework. This framework integrates habitat selection at multiple scales to obtain an appropriate estimate of availability for encounters. Using this approach, we related encounter probabilities to landscape resources. The RSFs describe habitat associations at four scales, home ranges within the study area, areas of overlap within home ranges, locations within areas of overlap, and encounters compared to other locations, which can be combined into a single scale-integrated RSF. We apply this method to intraspecific encounter data from two species: white-tailed deer (Odocoileus virginianus) and elk (Cervus elaphus) and interspecific encounter data from a two-species system of caribou (Rangifer tarandus) and coyote (Canis latrans). Our method produced scale-integrated RSFs that represented the relative probability of encounter. The predicted spatial distribution of encounters obtained based on this scale-integrated approach produced distributions that more accurately predicted novel encounters than a naïve approach or any individual scale alone. Our results highlight the importance of accounting for the conditional nature of habitat selection in estimating the habitat associations of animal encounters as opposed to 'naïve' comparisons of encounter locations with general availability. This method has direct relevance for testing hypotheses about the relationship between habitat and social or predator-prey behaviour and generating spatial predictions of encounters. Such spatial predictions may be vital for understanding the distribution of encounters driving disease transmission, predation rates and other population and community-level processes.
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Affiliation(s)
- Michael E Egan
- Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, Illinois, USA
| | - Nicole T Gorman
- Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, Illinois, USA
| | - Storm Crews
- Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, Illinois, USA
| | - Michael W Eichholz
- Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, Illinois, USA
| | - Dan Skinner
- Illinois Department of Natural Resources, Division of Wildlife Resources, Springfield, Illinois, USA
| | - Peter E Schlichting
- Illinois Department of Natural Resources, Division of Wildlife Resources, Springfield, Illinois, USA
| | | | - Eric J Bergman
- Colorado Parks and Wildlife, Fort Collins, Colorado, USA
| | - E Hance Ellington
- Department of Wildlife Ecology and Conservation, Range Cattle Research and Education Center, University of Florida, Ona, Florida, USA
| | - Guillaume Bastille-Rousseau
- Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, Illinois, USA
- School of Biological Sciences, Southern Illinois University, Carbondale, Illinois, USA
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2
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Gilbertson MLJ, Hart SN, VanderWaal K, Onorato D, Cunningham M, VandeWoude S, Craft ME. Seasonal changes in network connectivity and consequences for pathogen transmission in a solitary carnivore. Sci Rep 2023; 13:17802. [PMID: 37853051 PMCID: PMC10584909 DOI: 10.1038/s41598-023-44815-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 10/12/2023] [Indexed: 10/20/2023] Open
Abstract
Seasonal variation in habitat use and animal behavior can alter host contact patterns with potential consequences for pathogen transmission dynamics. The endangered Florida panther (Puma concolor coryi) has experienced significant pathogen-induced mortality and continues to be at risk of future epidemics. Prior research has found increased panther movement in Florida's dry versus wet seasons, which may affect panther population connectivity and seasonally increase potential pathogen transmission. Our objective was to determine if Florida panthers are more spatially connected in dry seasons relative to wet seasons, and test if identified connectivity differences resulted in divergent predicted epidemic dynamics. We leveraged extensive panther telemetry data to construct seasonal panther home range overlap networks over an 11 year period. We tested for differences in network connectivity, and used observed network characteristics to simulate transmission of a broad range of pathogens through dry and wet season networks. We found that panthers were more spatially connected in dry seasons than wet seasons. Further, these differences resulted in a trend toward larger and longer pathogen outbreaks when epidemics were initiated in the dry season. Our results demonstrate that seasonal variation in behavioral patterns-even among largely solitary species-can have substantial impacts on epidemic dynamics.
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Affiliation(s)
- Marie L J Gilbertson
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, MN, 55108, USA.
- Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - S Niamh Hart
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, MN, 55108, USA
| | - Kimberly VanderWaal
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, MN, 55108, USA
| | - Dave Onorato
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Naples, FL, 34114, USA
| | - Mark Cunningham
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Gainesville, FL, 32601, USA
| | - Sue VandeWoude
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Meggan E Craft
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, MN, 55108, USA
- Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN, 55108, USA
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Asa GA, Fauk NK, Ratu M, Dent E, Ward PR. Understanding actions and challenges in protecting older people during covid-19 pandemic in indonesia: A qualitative study with female caregivers. PLoS One 2023; 18:e0273761. [PMID: 36947503 PMCID: PMC10032487 DOI: 10.1371/journal.pone.0273761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 03/03/2023] [Indexed: 03/23/2023] Open
Abstract
COVID-19 has rapidly impacted societies on a global scale, with older people among the most affected. To care for older people living in their own homes, female family caregivers play a pivotal role. The current study aimed to explore the actions of female family caregivers and the challenges they faced in taking care of older people living at homes during the COVID-19 pandemic in Belu district, Indonesia. This qualitative study involved twenty female family caregivers, who were recruited using a combination of purposive and snowball sampling techniques. Findings were grouped into two main categories: (i) actions of female family caregivers in taking care of older adults during the COVID-19 pandemic. These included limiting both visitations of extended family members and older adults' activities outside homes; explaining the virus to older adults and controlling their access to news, social media and smartphones; providing nutrition, supplement and maintaining daily diets; and (ii) challenges they faced in taking care of older adults included excessive fear of contracting COVID-19 and possibility of transmitting it to older people; feeling stressed; tired and overburdened. The study highlights the significant role family caregivers played to protect older people living at home. The findings can inform government to develop intervention programs that address and support the needs of both family caregivers and older people living at home.
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Affiliation(s)
- Gregorius Abanit Asa
- Research Centre for Public Health, Equity and Human Flourishing (PHEHF), Torrens University Australia, Adelaide, South Australia, Australia
- Sanggar Belajar Alternatif (SALT), Atambua, Nusa Tenggara Timur, Indonesia
| | - Nelsensius Klau Fauk
- Research Centre for Public Health, Equity and Human Flourishing (PHEHF), Torrens University Australia, Adelaide, South Australia, Australia
- Institute of Resource Governance and Social Change, Kupang, Indonesia
| | - Melkianus Ratu
- Program Studi Keperawatan, Universitas Timor, Timor Tengah Utara, Nusa Tenggara Timur, Indonesia
| | - Elsa Dent
- Research Centre for Public Health, Equity and Human Flourishing (PHEHF), Torrens University Australia, Adelaide, South Australia, Australia
| | - Paul Russell Ward
- Research Centre for Public Health, Equity and Human Flourishing (PHEHF), Torrens University Australia, Adelaide, South Australia, Australia
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Islam MR, Bulut U, Feria-Arroyo TP, Tyshenko MG, Oraby T. Modeling the Impact of Climate Change on Cervid Chronic Wasting Disease in Semi-Arid South Texas. FRONTIERS IN EPIDEMIOLOGY 2022; 2:889280. [PMID: 38455276 PMCID: PMC10910938 DOI: 10.3389/fepid.2022.889280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/01/2022] [Indexed: 03/09/2024]
Abstract
Chronic wasting disease (CWD) is a spongiform encephalopathy disease caused by the transmission of infectious prion agents. CWD is a fatal disease that affects wild and farmed cervids in North America with few cases reported overseas. Social interaction of cervids, feeding practices by wildlife keepers and climate effects on the environmental carrying capacity all can affect CWD transmission in deer. Wildlife deer game hunting is economically important to the semi-arid South Texas region and is affected by climate change. In this paper, we model and investigate the effect of climate change on the spread of CWD using typical climate scenarios. We use a system of impulsive differential equations to depict the transmission of CWD between different age groups and gender of cervids. The carrying capacity and contact rates are assumed to depend on climate. Due to the polygamy of bucks, we use mating rates that depend on the number of bucks and does. We analyze the stability of the model and use simulations to study the effect of harvesting (culling) on eradicating the disease, given the climate of South Texas. We use typical climate change scenarios based on published data and our assumptions. For the climate indicator, we calculated and utilized the Standard Precipitation Evapotranspiration Index (SPEI). We found that climate change might hinder the efforts to reduce and effectively manage CWD as it becomes endemic to South Texas. The model shows the extinction of the deer population from this region is a likely outcome.
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Affiliation(s)
- Md Rafiul Islam
- Department of Mathematics, Iowa State University, Ames, IA, United States
| | - Ummugul Bulut
- Department of Mathematical, Physical, and Engineering Sciences, Texas A&M University-San Antonio, San Antonio, TX, United States
| | | | | | - Tamer Oraby
- School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, TX, United States
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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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Nurses' Actions to Protect Their Families from COVID-19: A Descriptive Qualitative Study. Glob Qual Nurs Res 2021; 8:23333936211014851. [PMID: 33997120 PMCID: PMC8110897 DOI: 10.1177/23333936211014851] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 12/21/2022] Open
Abstract
As health service providers, nurses are at a high risk of COVID-19 infection, as are their family members who live with them. This study aimed to explore nurses' actions to protect their families from COVID-19 in Indonesia. This qualitative descriptive study included seventeen nurses who were chosen using the snowball sampling technique. The semi structured interviews explored nurses' actions and behavior, and comparative analysis was performed to analyze the data. The study identified four themes: nurses modified their behavior and environments to protect their families, provided supplements and nutritious food, enhanced their families' knowledge and awareness of COVID-19, and protected their families from social stigma. Nurses play active roles in the health of their family members. The government should support nurses in their roles so that they can remain healthy while caring for COVID-19 patients, and not transmit COVID-19 to their own families.
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Webber QMR, Vander Wal E. Heterogeneity in social network connections is density-dependent: implications for disease dynamics in a gregarious ungulate. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02860-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Cojocaru MG, Migot T, Jaber A. Controlling infection in predator-prey systems with transmission dynamics. Infect Dis Model 2020; 5:1-11. [PMID: 31891013 PMCID: PMC6933197 DOI: 10.1016/j.idm.2019.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/07/2019] [Accepted: 12/07/2019] [Indexed: 11/30/2022] Open
Abstract
We propose in this paper a prophylactic treatment strategy for a predator-prey system. The objective is to fight against the propagation of an infectious disease within two populations, one of which preys on the other. This propagation is modeled by means of an SIS (susceptible-infectious-susceptible) epidemic model with vital dynamics and infection propagation in both species through contact and predation, including mortality rates in both populations due directly to the disease. Treatment strategies are represented by new parameters modeling the uptake rates in the populations. We analyze the effect of various treatment strategy scenarios (prey only, predator only, or both) via their uptake rates and possible cost structures, on the size of the infected populations. We illustrate if and when applying such preventive treatments lead to a disease prevalence drop in both populations. We conduct our study using an optimal control model seeking to minimize the treatment cost(s), subject to the transmission dynamics and predator-prey dynamics.
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Affiliation(s)
- M-G Cojocaru
- Department of Mathematics and Statistics, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - T Migot
- Department of Mathematics and Statistics, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - A Jaber
- Department of Mathematics and Statistics, University of Guelph, Guelph, ON, N1G 2W1, Canada.,Department of Mathematics, College of Science, University of Al-Mustansiriyah, Baghdad, Iraq
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Maji C, Mukherjee D, Kesh D. Deterministic and stochastic analysis of an eco-epidemiological model. J Biol Phys 2018; 44:17-36. [PMID: 28988403 PMCID: PMC5834997 DOI: 10.1007/s10867-017-9472-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 09/20/2017] [Indexed: 10/18/2022] Open
Abstract
Chronic wasting disease (CWD) is a contagious prion disease among the deer family that has the potential to disrupt the ecosystems where deer occur in abundance. To understand the dynamics of this emerging infectious disease, we consider a simple eco-epidemic model where the host population is infected by CWD. Boundedness of the system is established. The structure of equilibria and their linearized stability are investigated. The persistence condition is discussed. By constructing a suitable Lyapunov function, we discuss the global stability of the endemic equilibrium. Local bifurcation (transcritical) around the boundary equilibria is developed. Sufficient conditions for the existence of Hopf-bifurcation are derived. Further, we have also introduced white type of noise into the system to investigate stochastic stability. This suggests that the deterministic model is robust with respect to stochastic perturbation. Some numerical simulations are performed to validate our results.
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Affiliation(s)
- Chandan Maji
- Department of Mathematics, Vivekananda College, Thakurpukur, 269 D.H. Road, Kolkata, 700063 India
| | - Debasis Mukherjee
- Department of Mathematics, Vivekananda College, Thakurpukur, 269 D.H. Road, Kolkata, 700063 India
| | - Dipak Kesh
- Centre for Mathematical Biology and Ecology, Department of Mathematics, Jadavpur University, Kolkata, 700032 India
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Mejía-Salazar MF, Goldizen AW, Menz CS, Dwyer RG, Blomberg SP, Waldner CL, Cullingham CI, Bollinger TK. Mule deer spatial association patterns and potential implications for transmission of an epizootic disease. PLoS One 2017; 12:e0175385. [PMID: 28388681 PMCID: PMC5384682 DOI: 10.1371/journal.pone.0175385] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 03/24/2017] [Indexed: 12/04/2022] Open
Abstract
Animal social behaviour can have important effects on the long-term dynamics of diseases. In particular, preferential spatial relationships between individuals can lead to differences in the rates of disease spread within a population. We examined the concurrent influence of genetic relatedness, sex, age, home range overlap, time of year, and prion disease status on proximal associations of adult Rocky Mountain mule deer (Odocoileus hemionus hemionus) in a chronic wasting disease endemic area. We also quantified the temporal stability of these associations across different sex, age, and disease status classes. We used three years of high frequency telemetry data from 74 individuals to record encounters within 25 m of each other, and to calculate seasonal home range overlap measured by volume of intersection (VI). The strength of pairwise spatial association between adult mule deer was independent of genetic relatedness, age and disease status. Seasonal variation in association strength was not consistent across years, perhaps due to annual changes in weather conditions. The influence of home range overlap on association strength varied seasonally, whereby associations were stronger in pre-rut and fawning than in the rest of the seasons. The sexes of individuals also interacted with both VI and season. At increasing levels of VI, associations were stronger between females than between males and between females and males. The strongest associations in pre-rut were between males, while the strongest in rut were between females and males. The temporal stability of associations was markedly dependant on the sex and the diagnosis of the associating pair. Our findings highlight the importance of considering concurrent effects of biological and environmental factors when seeking to understand the role of social preference in behavioural ecology and disease spread. Applying this knowledge in epidemiological modelling will shed light on the dynamics of disease transmission among mule deer.
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Affiliation(s)
| | - Anne W. Goldizen
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Clementine S. Menz
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Ross G. Dwyer
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Simon P. Blomberg
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Cheryl L. Waldner
- Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | | | - Trent K. Bollinger
- Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Canadian Wildlife Health Cooperative (CWHC), Saskatoon, Saskatchewan, Canada
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Uehlinger FD, Johnston AC, Bollinger TK, Waldner CL. Systematic review of management strategies to control chronic wasting disease in wild deer populations in North America. BMC Vet Res 2016; 12:173. [PMID: 27549119 PMCID: PMC4994292 DOI: 10.1186/s12917-016-0804-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 08/18/2016] [Indexed: 01/01/2023] Open
Abstract
Background Chronic wasting disease (CWD) is a contagious, fatal prion disease affecting cervids in a growing number of regions across North America. Projected deer population declines and concern about potential spread of CWD to other species warrant strategies to manage this disease. Control efforts to date have been largely unsuccessful, resulting in continuing spread and increasing prevalence. This systematic review summarizes peer-reviewed published reports describing field-applicable CWD control strategies in wild deer populations in North America using systematic review methods. Ten databases were searched for peer-reviewed literature. Following deduplication, relevance screening, full-text appraisal, subject matter expert review and qualitative data extraction, nine references were included describing four distinct management strategies. Results Six of the nine studies used predictive modeling to evaluate control strategies. All six demonstrated one or more interventions to be effective but results were dependant on parameters and assumptions used in the model. Three found preferential removal of CWD infected deer to be effective in reducing CWD prevalence; one model evaluated a test and slaughter strategy, the other selective removal of infected deer by predators and the third evaluated increased harvest of the sex with highest prevalence (males). Three models evaluated non-selective harvest of deer. There were only three reports that examined primary data collected as part of observational studies. Two of these studies supported the effectiveness of intensive non-selective culling; the third study did not find a difference between areas that were subjected to culling and those that were not. Seven of the nine studies were conducted in the United States. Conclusions This review highlights the paucity of evaluated, field-applicable control strategies for CWD in wild deer populations. Knowledge gaps in the complex epidemiology of CWD and the intricacies inherent to prion diseases currently pose significant challenges to effective control of this disease in wild deer in North America. Electronic supplementary material The online version of this article (doi:10.1186/s12917-016-0804-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- F D Uehlinger
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, S7N 5B4, Canada.
| | - A C Johnston
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, S7N 5B4, Canada
| | - T K Bollinger
- Canadian Wildlife Health Cooperative, Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, S7N 5B4, Canada
| | - C L Waldner
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, S7N 5B4, Canada
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Abstract
Infectious disease dynamics are determined, to a great extent, by the social structure of the host. We evaluated sociality, or the tendency to form groups, in Rocky Mountain mule deer (Odocoileus hemionus hemionus) from a chronic wasting disease (CWD) endemic area in Saskatchewan, Canada, to better understand factors that may affect disease transmission. Using group size data collected on 365 radio-collared mule deer (2008–2013), we built a generalized linear mixed model (GLMM) to evaluate whether factors such as CWD status, season, habitat and time of day, predicted group occurrence. Then, we built another GLMM to determine factors associated with group size. Finally, we used 3 measures of group size (typical, mean and median group sizes) to quantify levels of sociality. We found that mule deer showing clinical signs of CWD were less likely to be reported in groups than clinically healthy deer after accounting for time of day, habitat, and month of observation. Mule deer groups were much more likely to occur in February and March than in July. Mixed-sex groups in early gestation were larger than any other group type in any season. Groups were largest and most likely to occur at dawn and dusk, and in open habitats, such as cropland. We discuss the implication of these results with respect to sociobiology and CWD transmission dynamics.
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13
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Daut EF, Lahodny G, Peterson MJ, Ivanek R. Interacting Effects of Newcastle Disease Transmission and Illegal Trade on a Wild Population of White-Winged Parakeets in Peru: A Modeling Approach. PLoS One 2016; 11:e0147517. [PMID: 26816214 PMCID: PMC4731398 DOI: 10.1371/journal.pone.0147517] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 01/05/2016] [Indexed: 11/19/2022] Open
Abstract
Illegal wildlife-pet trade can threaten wildlife populations directly from overharvest, but also indirectly as a pathway for introduction of infectious diseases. This study evaluated consequences of a hypothetical introduction of Newcastle disease (ND) into a wild population of Peru's most trafficked psittacine, the white-winged parakeet (Brotogeris versicolurus), through release of infected confiscated individuals. We developed two mathematical models that describe ND transmission and the influence of illegal harvest in a homogeneous (model 1) and age-structured population of parakeets (model 2). Infection transmission dynamics and harvest were consistent for all individuals in model 1, which rendered it mathematically more tractable compared to the more complex, age-structured model 2 that separated the host population into juveniles and adults. We evaluated the interaction of ND transmission and harvest through changes in the basic reproduction number (R0) and short-term host population dynamics. Our findings demonstrated that ND introduction would likely provoke considerable disease-related mortality, up to 24% population decline in two years, but high harvest rates would dampen the magnitude of the outbreak. Model 2 produced moderate differences in disease dynamics compared to model 1 (R0 = 3.63 and 2.66, respectively), but highlighted the importance of adult disease dynamics in diminishing the epidemic potential. Therefore, we suggest that future studies should use a more realistic, age-structured model. Finally, for the presumptive risk that illegal trade of white-winged parakeets could introduce ND into wild populations, our results suggest that while high harvest rates may have a protective effect on the population by reducing virus transmission, the combined effects of high harvest and disease-induced mortality may threaten population survival. These results capture the complexity and consequences of the interaction between ND transmission and harvest in a wild parrot population and highlight the importance of preventing illegal trade.
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Affiliation(s)
- Elizabeth F. Daut
- Schubot Exotic Bird Health Center, Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Glenn Lahodny
- Department of Mathematics, Texas A&M University, College Station, Texas, United States of America
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Markus J. Peterson
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Renata Ivanek
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
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14
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Modeling and analysis of a temperature-driven outbreak of waterfowl disease in the Upper Mississippi River. Ecol Modell 2016. [DOI: 10.1016/j.ecolmodel.2015.09.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Manlove KR, Cassirer EF, Cross PC, Plowright RK, Hudson PJ. Costs and benefits of group living with disease: a case study of pneumonia in bighorn lambs (Ovis canadensis). Proc Biol Sci 2015; 281:rspb.2014.2331. [PMID: 25377464 DOI: 10.1098/rspb.2014.2331] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Group living facilitates pathogen transmission among social hosts, yet temporally stable host social organizations can actually limit transmission of some pathogens. When there are few between-subpopulation contacts for the duration of a disease event, transmission becomes localized to subpopulations. The number of per capita infectious contacts approaches the subpopulation size as pathogen infectiousness increases. Here, we illustrate that this is the case during epidemics of highly infectious pneumonia in bighorn lambs (Ovis canadensis). We classified individually marked bighorn ewes into disjoint seasonal subpopulations, and decomposed the variance in lamb survival to weaning into components associated with individual ewes, subpopulations, populations and years. During epidemics, lamb survival varied substantially more between ewe-subpopulations than across populations or years, suggesting localized pathogen transmission. This pattern of lamb survival was not observed during years when disease was absent. Additionally, group sizes in ewe-subpopulations were independent of population size, but the number of ewe-subpopulations increased with population size. Consequently, although one might reasonably assume that force of infection for this highly communicable disease scales with population size, in fact, host social behaviour modulates transmission such that disease is frequency-dependent within populations, and some groups remain protected during epidemic events.
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Affiliation(s)
- Kezia R Manlove
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA
| | | | - Paul C Cross
- US Geological Survey, Northern Rocky Mountain Science Center, Bozeman, MT 59715, USA
| | - Raina K Plowright
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Peter J Hudson
- Department of Biology and Huck Institute for Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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Russell RE, Gude JA, Anderson NJ, Ramsey JM. Identifying priority chronic wasting disease surveillance areas for mule deer in Montana. J Wildl Manage 2015. [DOI: 10.1002/jwmg.914] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Robin E. Russell
- US Geological Survey; National Wildlife Health Center; 6006 Schroeder Road Madison WI 53711 USA
| | - Justin A. Gude
- Montana Fish; Wildlife and Parks; 1420 East 6th Avenue Helena MT 59620 USA
| | - Neil J. Anderson
- Montana Fish; Wildlife, and Parks; 1400 South 19th Avenue Bozeman MT 59717 USA
| | - Jennifer M. Ramsey
- Montana Fish; Wildlife, and Parks; 1400 South 19th Avenue Bozeman MT 59717 USA
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