1
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Everest DJ, Green C, Dastjerdi A, Davies H, Cripps R, McKinney C, Podgornik G, Stinson M, O'Hare S, Sapsford B, Mill A, Van der Waal Z, Robinson N, Trotter S, Shuttleworth CM. Opportunistic viral surveillance confirms the ongoing disease threat grey squirrels pose to sympatric red squirrel populations in the UK. Vet Rec 2023; 192:e2834. [PMID: 37024300 DOI: 10.1002/vetr.2834] [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: 09/08/2022] [Revised: 12/29/2022] [Accepted: 03/01/2023] [Indexed: 04/08/2023]
Abstract
BACKGROUND Red Squirrels United was a UK landscape-scale grey squirrel management programme undertaken between 2016 and 2020. METHODS A total of 11034 grey squirrels were removed by culling, with 1506 necropsied and 1405 suitable for adenovirus (AdV) or squirrelpox virus (SQPV) quantitative PCR (qPCR) analysis. Spleen, lip or hair were extracted, and DNA was isolated, with samples tested in duplicate by qPCR. RESULTS Of 1378 tissue samples, 43% were positive for AdV and 10% for SQPV. Of 1031 hair samples, 11% were positive for AdV and 10% for SQPV. Overall, 762 of 1405 (54%) animals were positive for one or both viruses. LIMITATIONS Ad hoc sampling was undertaken from limited geographical areas but provided the only dataset from that period, instead of extrapolating from historical data. CONCLUSIONS The grey squirrel is an asymptomatic reservoir host for AdV and SQPV. Interspecific infection transmission potential is demonstrated. Grey squirrel management by culling is essential for mainland red squirrel viability until other suitable management tools are available.
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Affiliation(s)
| | - Chalin Green
- Animal and Plant Health Agency-Weybridge, Addlestone, UK
| | | | - Hannah Davies
- Animal and Plant Health Agency-Weybridge, Addlestone, UK
| | - Rachel Cripps
- Lancashire Wildlife Trust, Seaforth Nature Reserve, Liverpool, UK
| | | | | | | | - Simon O'Hare
- Northumberland Wildlife Trust, Newcastle Upon Tyne, UK
| | | | - Aileen Mill
- Centre for Wildlife Management, School of Biology, Newcastle University, Newcastle Upon Tyne, UK
| | - Zelda Van der Waal
- Centre for Wildlife Management, School of Biology, Newcastle University, Newcastle Upon Tyne, UK
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2
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Wauters LA, Lurz PWW, Santicchia F, Romeo C, Ferrari N, Martinoli A, Gurnell J. Interactions between native and invasive species: A systematic review of the red squirrel-gray squirrel paradigm. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1083008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
The eastern gray squirrel (Sciurus carolinensis) has been labeled as one of the 100 worst invasive alien species by the IUCN. In Europe, the species has been introduced to Britain, Ireland and Italy, and its subsequent spread has resulted in wide-scale extinction of native Eurasian red squirrels (Sciurus vulgaris) from the areas colonized by the gray squirrel. This replacement of a native by an alien competitor is one of the best documented cases of the devastating effects of biological invasions on native fauna. To understand how this replacement occurs, we present a systematic review of the literature on competition and interactions between red and gray squirrels. We describe the patterns of red and gray squirrel distribution in those parts of Europe where gray squirrels occur and summarize the evidence on the different processes and mechanisms determining the outcome of competition between the native and alien species including the influence of predators and pathogens. Some of the drivers behind the demise of the red squirrel have been intensively studied and documented in the past 30 years, but recent field studies and mathematical models revealed that the mechanisms underlying the red-gray paradigm are more complex than previously thought and affected by landscape-level processes. Therefore, we consider habitat type and multi-species interactions, including host-parasite and predator-prey relationships, to determine the outcome of the interaction between the two species and to better address gray squirrel control efforts.
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3
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Wang S, Deng T, Zhang J, Li Y. Global economic costs of mammal invasions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159479. [PMID: 36265628 DOI: 10.1016/j.scitotenv.2022.159479] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/05/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Invasive alien mammals cause huge adverse ecological impact on human society and natural ecosystems. Although studies have estimated economic costs of mammal invasions at regional scales, there is lacking the large-scale comprehensive assessment of currency costs for this taxon. Here, we estimated the economic cost of invasive alien mammals on a global scale using the most comprehensive global database compiling economic costs of invasive species (InvaCost). From 1960 to 2021, mammal invasions caused costs (summing damage costs and management costs) of US$ 462.49 billion to the global economy, while the total amount of robust costs reached US$ 52.49 billion. The majority of the total economic costs corresponded to damage costs (90.27 %), while only 7.43 % were related to management cost. Economic costs showed an increasing trend over time. The distribution of costs was uneven among taxonomic groups and regions, with the global total cost highly biasing toward to 5 species (European rabbit, Domestic cat, Black rat, Wild boar and Coypu), and North America reporting much higher costs (60.78 % of total economic costs) than other regions. The total costs were borne by agriculture, environment, authorities stakeholders and other sectors. Geographic and taxonomic biases suggested that total economic costs caused by invasive alien mammals were underestimated. Integrated research efforts are needed to fill in knowledge gaps in the economic costs generated by mammal invasions and to identify the drivers of the economic costs.
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Affiliation(s)
- Siqi Wang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan, Beijing 100049, China
| | - Teng Deng
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan, Beijing 100049, China
| | - Jiaqi Zhang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan, Beijing 100049, China
| | - Yiming Li
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan, Beijing 100049, China; School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China.
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4
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Lee CC, Hsu HW, Lin CY, Gustafson N, Matsuura K, Lee CY, Yang CCS. First Polycipivirus and Unmapped RNA Virus Diversity in the Yellow Crazy Ant, Anoplolepis gracilipes. Viruses 2022; 14:v14102161. [PMID: 36298716 PMCID: PMC9612232 DOI: 10.3390/v14102161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 12/01/2022] Open
Abstract
The yellow crazy ant, Anoplolepis gracilipes is a widespread invasive ant that poses significant threats to local biodiversity. Yet, compared to other global invasive ant species such as the red imported fire ant (Solenopsis invicta) or the Argentine ant (Linepithema humile), little is known about the diversity of RNA viruses in the yellow crazy ant. In the current study, we generated a transcriptomic database for A. gracilipes using a high throughput sequencing approach to identify new RNA viruses and characterize their genomes. Four virus species assigned to Dicistroviridae, two to Iflaviridae, one to Polycipiviridae, and two unclassified Riboviria viruses were identified. Detailed genomic characterization was carried out on the polycipivirus and revealed that this virus comprises 11,644 nucleotides with six open reading frames. Phylogenetic analysis and pairwise amino acid identity comparison classified this virus into the genus Sopolycivirus under Polycipiviridae, which is tentatively named "Anoplolepis gracilipes virus 3 (AgrV-3)". Evolutionary analysis showed that AgrV-3 possesses a high level of genetic diversity and elevated mutation rate, combined with the common presence of multiple viral strains within single worker individuals, suggesting AgrV-3 likely evolves following the quasispecies model. A subsequent field survey placed the viral pathogen "hotspot" of A. gracilipes in the Southeast Asian region, a pattern consistent with the region being recognized as part of the ant's native range. Lastly, infection of multiple virus species seems prevalent across field colonies and may have been linked to the ant's social organization.
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Affiliation(s)
- Chih-Chi Lee
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 6068502, Japan
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto 6110011, Japan
- Department of Evolutionary and Environmental Biology, Institute of Evolution, University of Haifa, Haifa 3498838, Israel
| | - Hung-Wei Hsu
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 6068502, Japan
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto 6110011, Japan
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Chun-Yi Lin
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto 6110011, Japan
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA
| | - Nicolas Gustafson
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Kenji Matsuura
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 6068502, Japan
| | - Chow-Yang Lee
- Department of Entomology, University of California, 900 University Avenue, Riverside, CA 92521, USA
| | - Chin-Cheng Scotty Yang
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Correspondence: ; Tel.: +1-540-231-3052
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5
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Shuttleworth CM, Everest D, Holmes P, Bell S, Cripps R. An Opportunistic Assessment of the Impact of Squirrelpox Disease Outbreaks upon a Red Squirrel Population Sympatric with Grey Squirrels in Wales. Animals (Basel) 2022; 12:ani12010099. [PMID: 35011205 PMCID: PMC8749610 DOI: 10.3390/ani12010099] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/27/2021] [Accepted: 12/29/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary In Europe, squirrelpox virus is carried by non-native grey squirrels and spread into native red squirrel populations. The virus causes a large proportion of infected red squirrels to die and contributes to local declines and the replacement by grey squirrels. There are relatively few published studies quantifying the impact of disease amongst red squirrels. We present findings from a short-term study in north Wales, United Kingdom. Abstract Native red squirrels (Sciurus vulgaris) persisted in the coastal mainland woodlands of northern Gwynedd whilst sympatric with an invasive grey squirrel (Sciurus carolinensis) population suppressed by culling. Squirrelpox disease in the red squirrel population was recorded in 2017 and 2020/21. An autumn 2020 outbreak was associated with only 17.4% of animals caught and marked in the preceding June known to be present in March 2021. Despite an opportunistic data collection lacking the rigour of empirical experimental design, we observed low local survival rates similar to previously published accounts reported during major squirrelpox outbreaks. The use of a conservation dog to detect red squirrel carcasses resulted in positive detection and confirmation of a temporal and spatial expansion of one disease outbreak. The study is the first in Wales to use conservation dogs and the findings reinforce the vital strategic importance of geographical isolation reducing sympatry of red with grey squirrels in European regions where the introduced congener is a source of the squirrelpox infection.
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Affiliation(s)
| | | | - Paul Holmes
- APHA Shrewsbury, Veterinary Investigation Centre, Shrewsbury SY1 4HD, UK; (P.H.); (S.B.)
| | - Suzi Bell
- APHA Shrewsbury, Veterinary Investigation Centre, Shrewsbury SY1 4HD, UK; (P.H.); (S.B.)
| | - Rachel Cripps
- Lancashire Wildlife Trust, Bamber Bridge PR5 6BY, UK;
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6
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Trojan hosts: the menace of invasive vertebrates as vectors of pathogens in the Southern Cone of South America. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02488-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Lin CY, Lee CC, Nai YS, Hsu HW, Lee CY, Tsuji K, Yang CCS. Deformed Wing Virus in Two Widespread Invasive Ants: Geographical Distribution, Prevalence, and Phylogeny. Viruses 2020; 12:v12111309. [PMID: 33203145 PMCID: PMC7696054 DOI: 10.3390/v12111309] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/10/2020] [Accepted: 11/13/2020] [Indexed: 12/16/2022] Open
Abstract
Spillover of honey bee viruses have posed a significant threat to pollination services, triggering substantial effort in determining the host range of the viruses as an attempt to understand the transmission dynamics. Previous studies have reported infection of honey bee viruses in ants, raising the concern of ants serving as a reservoir host. Most of these studies, however, are restricted to a single, local ant population. We assessed the status (geographical distribution/prevalence/viral replication) and phylogenetic relationships of honey bee viruses in ants across the Asia–Pacific region, using deformed wing virus (DWV) and two widespread invasive ants, Paratrechina longicornis and Anoplolepis gracilipes, as the study system. DWV was detected in both ant species, with differential geographical distribution patterns and prevenance levels between them. These metrics, however, are consistent across the geographical range of the same ant species. Active replication was only evident in P. longicornis. We also showed that ant-associated DWV is genetically similar to that isolated from Asian populations of honey bees, suggesting that local acquisition of DWV by the invasive ants may have been common at least in some of our sampled regions. Transmission efficiency of DWV to local arthropods mediated by ant, however, may vary across ant species.
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Affiliation(s)
- Chun-Yi Lin
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto 611-0011, Japan; (C.-Y.L.); (C.-C.L.); (H.-W.H.)
| | - Chih-Chi Lee
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto 611-0011, Japan; (C.-Y.L.); (C.-C.L.); (H.-W.H.)
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Yu-Shin Nai
- Department of Entomology, National Chung Hsing University, Taichung 402204, Taiwan;
| | - Hung-Wei Hsu
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto 611-0011, Japan; (C.-Y.L.); (C.-C.L.); (H.-W.H.)
- Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Chow-Yang Lee
- Department of Entomology, University of California, 900 University Avenue, Riverside, CA 92521, USA;
| | - Kazuki Tsuji
- Department of Subtropical Agro-Environmental Sciences, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-0213, Japan;
| | - Chin-Cheng Scotty Yang
- Department of Entomology, National Chung Hsing University, Taichung 402204, Taiwan;
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Correspondence: ; Tel.: +886-4-2284-0361 (ext. 540)
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8
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Shuttleworth CM, Everest DJ, Dastjerdi A, Birks J, Hayward MW. Pine marten scat holds few clues for squirrel disease. Vet Rec 2019; 185:698. [PMID: 31806837 DOI: 10.1136/vr.l6687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- C M Shuttleworth
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW
| | - D J Everest
- Animal and Plant Health Agency-Weybridge, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB
| | - A Dastjerdi
- Animal and Plant Health Agency-Weybridge, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB
| | - Jds Birks
- Swift Ecology, Fartown Barn, Pensax, Abberley, Worcestershire WR6 6AE
| | - M W Hayward
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
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9
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Disease transmission and introgression can explain the long-lasting contact zone of modern humans and Neanderthals. Nat Commun 2019; 10:5003. [PMID: 31676766 PMCID: PMC6825168 DOI: 10.1038/s41467-019-12862-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 09/26/2019] [Indexed: 12/11/2022] Open
Abstract
Neanderthals and modern humans both occupied the Levant for tens of thousands of years prior to the spread of modern humans into the rest of Eurasia and their replacement of the Neanderthals. That the inter-species boundary remained geographically localized for so long is a puzzle, particularly in light of the rapidity of its subsequent movement. Here, we propose that infectious-disease dynamics can explain the localization and persistence of the inter-species boundary. We further propose, and support with dynamical-systems models, that introgression-based transmission of alleles related to the immune system would have gradually diminished this barrier to pervasive inter-species interaction, leading to the eventual release of the inter-species boundary from its geographic localization. Asymmetries between the species in the characteristics of their associated ‘pathogen packages’ could have generated feedback that allowed modern humans to overcome disease burden earlier than Neanderthals, giving them an advantage in their subsequent spread into Eurasia. Modern humans and Neanderthals coexisted in the Levant for tens of thousands of years before modern humans spread and replaced Neanderthals. Here, Greenbaum et al. develop a model showing that transmission of disease and genes can explain the maintenance and then collapse of this contact zone.
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10
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Chantrey J, Dale T, Jones D, Begon M, Fenton A. The drivers of squirrelpox virus dynamics in its grey squirrel reservoir host. Epidemics 2019; 28:100352. [PMID: 31327730 DOI: 10.1016/j.epidem.2019.100352] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/02/2019] [Accepted: 07/02/2019] [Indexed: 11/30/2022] Open
Abstract
Many pathogens of conservation concern circulate endemically within natural wildlife reservoir hosts and it is imperative to understand the individual and ecological drivers of natural transmission dynamics, if any threat to a related endangered species is to be assessed. Our study highlights the key drivers of infection and shedding dynamics of squirrelpox virus (SQPV) in its reservoir grey squirrel (Sciurus carolinensis) population. To clarify SQPV dynamics in this population, longitudinal data from a 16-month mark-recapture study were analysed, combining serology with real-time quantitative PCR to identify periods of acute viraemia and chronic viral shedding. At the population level, we found SQPV infection prevalence, viral load and shedding varied seasonally, peaking in autumn and early spring. Individually, SQPV was shown to be a chronic infection in >80% of grey squirrels, with viral loads persisting over time and bouts of potential recrudescence or reinfection occurring. A key recurring factor significantly associated with SQPV infection risk was the presence of co-infecting squirrel adenovirus (ADV). In dual infected squirrels, longitudinal analysis showed that prior ADV viraemia increased the subsequent SQPV load in the blood. However, there was a strong, negative association between prior ADV viraemia and subsequent SQPV shedding from the forearm, probably caused by ADV prolonging the SQPV acute viraemic phase, so delaying onset of the chronic shedding phase, and thereby altering viral shedding patterns over the time scales examined here. Hence, co-circulating ADV infection may be involved in mediating both the quantitative levels of SQPV infection and the timing and degree of subsequent infectiousness of grey squirrels.
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Affiliation(s)
- Julian Chantrey
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB, UK; Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Neston, CH64 7TE, UK.
| | - Timothy Dale
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB, UK
| | - David Jones
- Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Neston, CH64 7TE, UK
| | - Michael Begon
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB, UK
| | - Andy Fenton
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB, UK
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11
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The diet of denning female European pine martens (Martes martes) in Galloway Forest District, South West Scotland, Great Britain. MAMMAL RES 2018. [DOI: 10.1007/s13364-018-0398-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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12
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Blackett TA, Simpson VR, Haugland S, Everest DJ, Muir CF, Smith KC, Mill AC. Mortalities, amyloidosis and other diseases in free-living red squirrels ( Sciurus vulgaris) on Jersey, Channel Islands. Vet Rec 2018; 183:503. [PMID: 30181130 DOI: 10.1136/vr.104779] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 06/14/2018] [Accepted: 07/06/2018] [Indexed: 11/04/2022]
Abstract
Between 2007 and 2014, 337 free-living red squirrels (Sciurus vulgaris) on Jersey, Channel Islands, were examined post mortem as part of a mortality and disease surveillance scheme. Road traffic accidents (RTAs) were attributable for 50.7 per cent (171/337) of the casualties, 34.4 per cent (116/337) succumbed to diseases including fatal exudative dermatitis (FED), 7.1 per cent (24/337) to predation, 6.5 per cent (22/337) to other trauma and 1.2 per cent (4/337) to suspected poisoning. Cat predation accounted for 5 per cent (17/337) of mortalities. Pathologies were diverse and individual animals were often identified with more than one disease process. Squirrelpox virus (SQPV) particles were not detected in selected cases examined by transmission electron microscopy (TEM). Amyloid was identified in 19.3 per cent (65/337) of squirrels, often in conjunction with inflammatory lesions like hepatic capillariasis. A consistent cause of amyloid accumulation was not identified, although there was a significant association of amyloidosis with hepatic capillariasis and FED. In addition to RTAs, amyloidosis and FED have been identified as important causes of squirrel morbidity and mortality on Jersey, while the underlying aetiology and predisposing factors for these two disease complexes are presently unclear. Disease, fragmented woodlands, an increasingly suburban habitat, along with various anthropogenic factors, may jeopardise the long-term viability of this island red squirrel population.
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Affiliation(s)
| | | | | | | | - Clare F Muir
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hatfield, UK
| | - Kenneth C Smith
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hatfield, UK
| | - Aileen C Mill
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
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13
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Robinson CV, Garcia de Leaniz C, James J, Cable J, Orozco‐terWengel P, Consuegra S. Genetic diversity and parasite facilitated establishment of the invasive signal crayfish ( Pacifastacus leniusculus) in Great Britain. Ecol Evol 2018; 8:9181-9191. [PMID: 30377493 PMCID: PMC6194297 DOI: 10.1002/ece3.4235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/01/2018] [Accepted: 05/03/2018] [Indexed: 11/25/2022] Open
Abstract
Successful establishment of non-native species is strongly influenced, among other factors, by the genetic variation of founding populations, which can be enhanced by multiple introductions through admixture. Coexisting pathogens can also facilitate the establishment of non-native species by detrimentally impacting on the native fauna acting as novel weapons. The signal crayfish (Pacifastacus leniusculus) is a highly invasive species, which has caused mass declines of native crayfish in Europe through displacement and transmission of the oomycete Aphanomyces astaci (crayfish plague), which is typically lethal to native European crayfish. However, whether Aphanomyces astaci may have facilitated the invasion of the signal crayfish is not known. We estimated the genetic diversity at microsatellite DNA loci, effective population size, and potential origins of seven infected and noninfected signal crayfish populations in Europe and one founder population in North America. Approximate Bayesian computation analysis and population structuring suggested multiple host introductions from diverse source populations, as well as higher heterozygosity among infected than uninfected populations, which could reflect a fitness advantage. Low effective population size, moderate heterozygosity, and lack of isolation by distance suggest that some invasive signal crayfish populations may not be fully established or that their genetic diversity may have been reduced by eradication attempts.
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Affiliation(s)
| | | | - Joanna James
- Cardiff UniversityCardiffWalesUK
- Environment AgencyBramptonUK
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14
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Romeo C, McInnes CJ, Dale TD, Shuttleworth C, Bertolino S, Wauters LA, Ferrari N. Disease, invasions and conservation: no evidence of squirrelpox virus in grey squirrels introduced to Italy. Anim Conserv 2018. [DOI: 10.1111/acv.12433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Romeo
- Department of Veterinary Medicine Università degli Studi di Milano Milan Italy
| | | | - T. D. Dale
- Institute of Integrative Biology University of Liverpool Liverpool UK
| | - C. Shuttleworth
- School of Environment, Natural Resources and Geography Bangor University Bangor Gwynedd UK
| | - S. Bertolino
- Department of Life Sciences and Systems Biology Università degli Studi di Torino Torino Italy
| | - L. A. Wauters
- Department of Theoretical and Applied Sciences Università degli Studi dell'Insubria Varese Italy
| | - N. Ferrari
- Department of Veterinary Medicine Università degli Studi di Milano Milan Italy
- Centro di Ricerca Coordinata Epidemiologia e Sorveglianza Molecolare delle Infezioni Università degli Studi di Milano Milan Italy
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15
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Marzal A, Møller AP, Espinoza K, Morales S, Luján-Vega C, Cárdenas-Callirgos JM, Mendo L, Álvarez-Barrientos A, González-Blázquez M, García-Longoria L, de Lope F, Mendoza C, Iannacone J, Magallanes S. Variation in malaria infection and immune defence in invasive and endemic house sparrows. Anim Conserv 2018. [DOI: 10.1111/acv.12423] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- A. Marzal
- Department of Anatomy, Cellular Biology and Zoology; University of Extremadura; Badajoz Spain
| | - A. P. Møller
- Ecologie Systématique Evolution; Université Paris-Sud; CNRS; AgroParisTech; Université Paris-Saclay; Orsay Cedex France
| | - K. Espinoza
- Department of Veterinary Medicine; Universidad Científica del Sur; Villa Peru
| | - S. Morales
- Department of Veterinary Medicine; Universidad Científica del Sur; Villa Peru
- Department of Animal and Public Health; Faculty of Veterinary Medicine; Universidad Nacional Mayor de San Marcos; San Borja Peru
| | - C. Luján-Vega
- Global Health Initiative; Wabash College; Crawfordsville Indiana USA
- Pharmacology and Toxicology Graduate Group; University of California; Davis USA
| | | | - L. Mendo
- Área de Gestión de fauna Silvestre; Autoridad Regional Ambiental; Gobierno Regional de San Martín; Tarapoto Perú
| | - A. Álvarez-Barrientos
- Servicio de Técnicas Aplicadas a las Biociencias; Universidad de Extremadura; Badajoz Spain
| | - M. González-Blázquez
- Department of Anatomy, Cellular Biology and Zoology; University of Extremadura; Badajoz Spain
| | - L. García-Longoria
- Department of Anatomy, Cellular Biology and Zoology; University of Extremadura; Badajoz Spain
| | - F. de Lope
- Department of Anatomy, Cellular Biology and Zoology; University of Extremadura; Badajoz Spain
| | - C. Mendoza
- Laboratorio de Análisis Clínico Moraleslab SAC; Morales San Martín Perú
| | - J. Iannacone
- Laboratorio de Ecología y Biodiversidad Animal; Universidad Nacional Federico Villarreal; El Agustino; Lima Perú
- Laboratorio de Parasitología; Universidad Ricardo Palma; Santiago de Surco; Lima Perú
| | - S. Magallanes
- Department of Anatomy, Cellular Biology and Zoology; University of Extremadura; Badajoz Spain
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16
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Borisevich SV, Stovba LF, Paveliev DI. POXVIRUS DISEASE OF SQUIRRELS (POXVIRIDAE, CHORDOPOXVIRINAE, SQPV - SQUIRREL POXVIRUS). Vopr Virusol 2018; 63:53-57. [PMID: 36494921 DOI: 10.18821/0507-4088-2018-63-2-53-57] [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: 01/20/2020] [Indexed: 06/17/2023]
Abstract
A new taxon of the subfamily Chordopoxvirinae that may represent a new genus of smallpox viruses is considered in this review. The distribution of gray squirrels (Sciurus carolinensis) throughout the UK during the 20th century and the decrease in the population of red squirrels (Sciurus vulgaris) is one of the most well-documented cases of ecological change of local fauna by the introduced species. The tendency to expand the distribution of the smallpox virus from Great Britain to the Western part of Europe has been noted. The genetic peculiarities of the genome of the poxvirus of squirrels, which determine its biological properties, as well as evolutionary relationships with other poxviruses, are separately described. Determination of the size of the genome by restriction analysis, sequencing of the whole genome, determination of the content of G/C nucleotide pairs, and functional mapping of the majority of genes made it possible to construct a phylogenetic tree. Phylogenetic analysis shows that this is a new representative of the subfamily Chordоpoxvirinae located between the viruses of the molluscum contagiosum and parapoxviruses. Serological and molecular biological methods are used to reveal and identify the causative agent of smallpox. The use of electron microscopy is limited in grey squirrels, due to the absence of organ damage and reproduction of the virus. Identification of the DNA of the causative agent of poxvirus of squirrels based on the use of different types of polymerase chain reaction (nested and in real time) overcomes all these limitations.
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Affiliation(s)
| | - L F Stovba
- 48th Central Scientific Research Institute
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17
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McGowan N, Scantlebury D, McInnes C, Reid N. Squirrelpox virus antibodies detected in red squirrels. Vet Rec 2018; 182:355. [PMID: 29572422 DOI: 10.1136/vr.k1296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Natasha McGowan
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL
| | - David Scantlebury
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL.,Institute for Global Food Security (IGFS), 13 Stranmillis Road, Belfast BT9 5AF
| | - Colin McInnes
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ
| | - Neil Reid
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL.,Institute for Global Food Security (IGFS), 13 Stranmillis Road, Belfast BT9 5AF
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18
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Verheggen FJ, Vogel H, Vilcinskas A. Behavioral and Immunological Features Promoting the Invasive Performance of the Harlequin Ladybird Harmonia axyridis. Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00156] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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19
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Kamenova S, Bartley T, Bohan D, Boutain J, Colautti R, Domaizon I, Fontaine C, Lemainque A, Le Viol I, Mollot G, Perga ME, Ravigné V, Massol F. Invasions Toolkit. ADV ECOL RES 2017. [DOI: 10.1016/bs.aecr.2016.10.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Young HS, Parker IM, Gilbert GS, Sofia Guerra A, Nunn CL. Introduced Species, Disease Ecology, and Biodiversity-Disease Relationships. Trends Ecol Evol 2016; 32:41-54. [PMID: 28029377 DOI: 10.1016/j.tree.2016.09.008] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/25/2016] [Accepted: 09/26/2016] [Indexed: 11/29/2022]
Abstract
Species introductions are a dominant component of biodiversity change but are not explicitly included in most discussions of biodiversity-disease relationships. This is a major oversight given the multitude of effects that introduced species have on both parasitism and native hosts. Drawing on both animal and plant systems, we review the competing mechanistic pathways by which biological introductions influence parasite diversity and prevalence. While some mechanisms - such as local changes in phylogenetic composition and global homogenization - have strong explanatory potential, the net effects of introduced species, especially at local scales, remain poorly understood. Integrative, community-scale studies that explicitly incorporate introduced species are needed to make effective predictions about the effects of realistic biodiversity change and conservation action on disease.
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Affiliation(s)
- Hillary S Young
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Ingrid M Parker
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Gregory S Gilbert
- Department of Environmental Studies, University of California, Santa Cruz, CA, USA
| | - Ana Sofia Guerra
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Charles L Nunn
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA; Duke Global Health Institute, Duke University, Durham, NC, USA
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21
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Hofmannová L, Romeo C, Štohanzlová L, Jirsová D, Mazzamuto MV, Wauters LA, Ferrari N, Modrý D. Diversity and host specificity of coccidia (Apicomplexa: Eimeriidae) in native and introduced squirrel species. Eur J Protistol 2016; 56:1-14. [DOI: 10.1016/j.ejop.2016.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/17/2016] [Accepted: 04/19/2016] [Indexed: 10/21/2022]
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22
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Dale TD, Watts PC, Jones D, Pounder K, Everest DJ, Begon ME, Chantrey J. Enhancement of wildlife disease surveillance using multiplex quantitative PCR: development of qPCR assays for major pathogens in UK squirrel populations. EUR J WILDLIFE RES 2016; 62:589-599. [PMID: 32214943 PMCID: PMC7088385 DOI: 10.1007/s10344-016-1031-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 06/22/2016] [Accepted: 07/03/2016] [Indexed: 11/22/2022]
Abstract
Rapid development in polymerase chain reaction (PCR) technology has revolutionised the speed and accuracy of many diagnostic assays. However, comparatively few wildlife epidemiological studies use quantitative PCR (qPCR) for pathogen detection, even fewer employ an internal control, to ensure confidence in negative results, and PCR's ability to multiplex and therefore detect several targets in a single reaction is underutilised. Here, we describe the development of two multiplex qPCR assays for the red and grey squirrel that detect the pathogens squirrelpox virus (SQPV) and adenovirus in squirrels (SADV), both of which cause mortality in the red squirrel. Both assays use a section of the squirrel phosphoglycerate kinase gene as an endogenous internal control that identifies and compensates for both, inadequate sampling or PCR inhibition. Tests on infected squirrel tissue demonstrate that simple swab samples (particularly from distal antebrachial skin) are sufficient to detect and identify the relative quantity of SQPV DNA in both squirrel species, while rectal swabs and blood cell pellets can be used to reliably indicate SADV infection. These assays are sensitive and specific with an endogenous internal control providing confidence in negative results and allowing comparison across laboratories. Using such assays should prove advantageous in wildlife studies with limited resources while allowing the maximum data yield.
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Affiliation(s)
- Timothy D. Dale
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
| | | | - David Jones
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Kieran Pounder
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
| | - David J. Everest
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, KT15 3NB UK
| | - Michael E. Begon
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
| | - Julian Chantrey
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
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23
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Everest DJ, Dastjerdi A, Cowen D, Gomm M, Shuttleworth CM, McInnes CJ, Deane D, Coulter L, Mill A, Rushton SP, Jackson NL, Litherland P. SQPV antibody detection in juvenile squirrels. Vet Rec 2016; 179:101-2. [DOI: 10.1136/vr.i3995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- David J. Everest
- APHA-Weybridge; Woodham Lane, New Haw Addlestone Surrey KT15 3NB
| | - Akbar Dastjerdi
- APHA-Weybridge; Woodham Lane, New Haw Addlestone Surrey KT15 3NB
| | - David Cowen
- National Wildlife Centre; APHA-York, Sand Hutton York North Yorkshire YO41 1LZ
| | - Matthew Gomm
- National Wildlife Centre; APHA-York, Sand Hutton York North Yorkshire YO41 1LZ
| | | | - Colin J. McInnes
- Moredun Research Institute; Pentlands Science Park, Bush Loan Penicuik Midlothian EH26 0PZ
| | - David Deane
- Moredun Research Institute; Pentlands Science Park, Bush Loan Penicuik Midlothian EH26 0PZ
| | - Lesley Coulter
- Moredun Research Institute; Pentlands Science Park, Bush Loan Penicuik Midlothian EH26 0PZ
| | - Aileen Mill
- School of Biology; Newcastle University Newcastle-upon-Tyne NE1 7RU
| | | | - Nicholas L. Jackson
- National Zoological Society of Wales; Welsh Mountain Zoo Colwyn Bay Conwy LL28 5UY
| | - Peter Litherland
- National Zoological Society of Wales; Welsh Mountain Zoo Colwyn Bay Conwy LL28 5UY
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24
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Fiegna C, Dagleish M, Coulter L, Milne E, Meredith A, Finlayson J, Di Nardo A, McInnes C. Host-pathogen dynamics of squirrelpox virus infection in red squirrels (Sciurus vulgaris). Vet Microbiol 2016; 182:18-27. [DOI: 10.1016/j.vetmic.2015.10.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/12/2015] [Accepted: 10/13/2015] [Indexed: 11/15/2022]
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25
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Chancellor G. Levels of selection in Darwin's Origin of Species. HISTORY AND PHILOSOPHY OF THE LIFE SCIENCES 2015; 37:131-157. [PMID: 26013643 DOI: 10.1007/s40656-015-0067-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 03/06/2015] [Indexed: 06/04/2023]
Abstract
References in Darwin's Origin of Species to competition between units of selection at and above the level of individual organisms are enumerated. In many cases these references clearly speak of natural selection and do not support the view that Darwin thought selection only occurred at the level of the individual organism. Darwin did see organismal selection as the main process by which varieties were created but he also espoused what is here termed community and varietal selection. He saw no essential difference between varieties and species and the references show that he also believed that selection could operate at the species level.
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26
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Affiliation(s)
- Andreas Vilcinskas
- Institute for Phytopathology and Applied Zoology, Justus-Liebig University of Giessen, Giessen, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Giessen, Germany
- * E-mail:
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27
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Replicating poxviruses for human cancer therapy. J Microbiol 2015; 53:209-18. [PMID: 25845536 DOI: 10.1007/s12275-015-5041-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/04/2015] [Accepted: 03/19/2015] [Indexed: 01/29/2023]
Abstract
Naturally occurring oncolytic viruses are live, replication-proficient viruses that specifically infect human cancer cells while sparing normal cell counterparts. Since the eradication of smallpox in the 1970s with the aid of vaccinia viruses, the vaccinia viruses and other genera of poxviruses have shown various degrees of safety and efficacy in pre-clinical or clinical application for human anti-cancer therapeutics. Furthermore, we have recently discovered that cellular tumor suppressor genes are important in determining poxviral oncolytic tropism. Since carcinogenesis is a multi-step process involving accumulation of both oncogene and tumor suppressor gene abnormalities, it is interesting that poxvirus can exploit abnormal cellular tumor suppressor signaling for its oncolytic specificity and efficacy. Many tumor suppressor genes such as p53, ATM, and RB are known to play important roles in genomic fidelity/maintenance. Thus, tumor suppressor gene abnormality could affect host genomic integrity and likely disrupt intact antiviral networks due to accumulation of genetic defects, which would in turn result in oncolytic virus susceptibility. This review outlines the characteristics of oncolytic poxvirus strains, including vaccinia, myxoma, and squirrelpox virus, recent progress in elucidating the molecular connection between oncogene/tumor suppressor gene abnormalities and poxviral oncolytic tropism, and the associated preclinical/clinical implications. I would also like to propose future directions in the utility of poxviruses for oncolytic virotherapy.
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28
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Hatcher MJ, Dick JTA, Paterson RA, Alexander ME, Bunke M, Dunn AM. Trait-Mediated Effects of Parasites on Invader-Native Interactions. HOST MANIPULATIONS BY PARASITES AND VIRUSES 2015. [PMCID: PMC7120441 DOI: 10.1007/978-3-319-22936-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Parasites have a variety of behavioural effects on their hosts, which can in turn affect species with which the host interacts. Here we review how these trait-mediated indirect effects of parasites can alter the outcomes of invader-native interactions, illustrating with examples from the literature and with particular regard to the invader-native crustacean systems studied in our laboratories. Parasites may potentially inhibit or exacerbate invasions via their effects on host behaviour, in addition to their direct virulence effects on hosts. In several crustacean systems, we have found that parasites influence both host predation rates on intra- and inter-guild prey and host vulnerability to being preyed upon. These trait effects can theoretically alter invasion impact and patterns of coexistence, as they indirectly affect interactions between predators and prey with the potential for further ramifications to other species in the food web. The fitness consequences of parasite-induced trait-mediated effects are rarely considered in traditional parasitological contexts, but demand attention in the context of ecological communities. We can regard these trait effects as a form of cryptic virulence that only becomes apparent when hosts are examined in the context of the other species with which they interact.
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29
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Chantrey J, Dale TD, Read JM, White S, Whitfield F, Jones D, McInnes CJ, Begon M. European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface. Ecol Evol 2014; 4:3788-99. [PMID: 25614793 PMCID: PMC4301051 DOI: 10.1002/ece3.1216] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/03/2014] [Accepted: 07/13/2014] [Indexed: 11/17/2022] Open
Abstract
Infectious disease introduced by non-native species is increasingly cited as a facilitator of
native population declines, but direct evidence may be lacking due to inadequate population and
disease prevalence data surrounding an outbreak. Previous indirect evidence and theoretical models
support squirrelpox virus (SQPV) as being potentially involved in the decline of red squirrels
(Sciurus vulgaris) following the introduction of the non-native gray squirrel
(Sciurus carolinensis) to the United Kingdom. The red squirrel is a major UK
conservation concern and understanding its continuing decline is important for any attempt to
mitigate the decline. The red squirrel–gray squirrel system is also exemplary of the
interplay between infectious disease (apparent competition) and direct competition in driving the
replacement of a native by an invasive species. Time series data from Merseyside are presented on
squirrel abundance and squirrelpox disease (SQPx) incidence, to determine the effect of the pathogen
and the non-native species on the native red squirrel populations. Analysis indicates that SQPx in
red squirrels has a significant negative impact on squirrel densities and their population growth
rate (PGR). There is little evidence for a direct gray squirrel impact; only gray squirrel presence
(but not density) proved to influence red squirrel density, but not red squirrel PGR. The dynamics
of red SQPx cases are largely determined by previous red SQPx cases, although previous infection of
local gray squirrels also feature, and thus, SQPV-infected gray squirrels are identified as
potentially initiating outbreaks of SQPx in red squirrels. Retrospective serology indicates that
approximately 8% of red squirrels exposed to SQPV may survive infection during an epidemic.
This study further highlights the UK red squirrel – gray squirrel system as a classic example
of a native species population decline strongly facilitated by infectious disease introduced by a
non-native species. It is therefore paramount that disease prevention and control measures are
integral in attempts to conserve red squirrels in the United Kingdom.
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Affiliation(s)
- Julian Chantrey
- Institute of Integrative Biology, University of Liverpool Biosciences Building, Crown Street, Liverpool, L69 7ZB, U.K
| | - Timothy D Dale
- Institute of Integrative Biology, University of Liverpool Biosciences Building, Crown Street, Liverpool, L69 7ZB, U.K
| | - Jonathan M Read
- Institute of Infection and Global Health, University of Liverpool Leahurst Campus, Neston, CH64 7TE, U.K
| | - Steve White
- Lancashire Wildlife Trust, Seaforth Nature Reserve Liverpool, L21 1JD, U.K
| | - Fiona Whitfield
- Lancashire Wildlife Trust, Seaforth Nature Reserve Liverpool, L21 1JD, U.K
| | - David Jones
- Institute of Infection and Global Health, University of Liverpool Leahurst Campus, Neston, CH64 7TE, U.K
| | - Colin J McInnes
- Moredun Institute, Pentlands Science Park Bush Loan, Penicuik, Midlothian, EH26 0PZ, U.K
| | - Michael Begon
- Institute of Integrative Biology, University of Liverpool Biosciences Building, Crown Street, Liverpool, L69 7ZB, U.K
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