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Manzoli DE, Saravia-Pietropaolo MJ, Arce SI, Percara A, Antoniazzi LR, Beldomenico PM. Specialist by preference, generalist by need: availability of quality hosts drives parasite choice in a natural multihost-parasite system. Int J Parasitol 2021; 51:527-534. [PMID: 33713648 DOI: 10.1016/j.ijpara.2020.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 11/24/2022]
Abstract
Encountering suitable hosts is key for parasite success. A general assumption for disease transmission is that the contact of a parasite with a potential host is driven by the density or relative frequency of hosts. That assumption ignores the potential role of differential host attractiveness for parasites that can drive the encounter of hosts. It has been posited that hosts may be chosen by parasites as a function of their suitability, but the existing literature addressing that hypothesis is still very scarce. In a natural system involving a parasitic Philornis botfly and its multiple bird hosts, there are profound differences in host quality. The Great Kiskadee tolerates and does not invest in resisting the infection, which makes it an optimal host. Alternative hosts are frequently used, but whilst some of them may be good options, others are bad alternatives. Here we examined the host selection processes that drive parasite dynamics in this system with 8 years of data from a longitudinal study under natural conditions. We found that the use of an alternative host was not driven by its density or relative frequency, but instead selection of these hosts was strongly dependent on availability of more suitable hosts. When optimal hosts are plentiful, the parasite tends to ignore alternative ones. As broods of optimal hosts become limited, good alternative hosts are targeted. The parasite chooses bad alternative hosts only when better alternatives are not sufficiently available. These results add evidence from a natural system that some parasites choose their hosts as a function of their profitability, and show that host selection by this parasite is plastic and context-dependent. Such findings could have important implications for the epidemiology of some parasitic and vector-borne infections which should be considered when modelling and managing those diseases. The facultative host selection observed here can be of high relevance for public health, animal husbandry, and biodiversity conservation, because reductions in the richness of hosts might cause humans, domestic animals, or endangered species to become increasingly targeted by parasites that can drive the encounter of hosts.
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Affiliation(s)
- Darío Ezequiel Manzoli
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina
| | - María José Saravia-Pietropaolo
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Sofía Irene Arce
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Alejandro Percara
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Leandro Raúl Antoniazzi
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Pablo Martín Beldomenico
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina.
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Pruvot M, Musiani M, Boyce MS, Kutz S, Orsel K. Integrating livestock management and telemetry data to assess disease transmission risk between wildlife and livestock. Prev Vet Med 2019; 174:104846. [PMID: 31765959 DOI: 10.1016/j.prevetmed.2019.104846] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 11/12/2019] [Accepted: 11/12/2019] [Indexed: 11/26/2022]
Abstract
Overlap of cattle and wild elk ranges in southwestern Alberta foothills is an opportunity for inter-species interactions. To assess the spatio-temporal patterns of disease transmission risk between cattle and elk, several risk indexes were defined to represent different transmission routes. Risk indexes were estimated by combining elk telemetry data obtained from 168 GPS-collared elk, and cattle management information obtained by interviews conducted in 16 cow-calf operations overlapping the elk home range. We assessed the bias resulting from ignoring cattle movement related to seasonnal grazing practices, and the impact of the assessment of spatio-temporal patterns of risk. Direct transmission risk indexes peaked during winter months, due to aggregation at higher densities of both elk and cattle on winter ranges and winter pastures, respectively. However, a summer peak also was observed when risk indexes were not adjusted for pasture area, due to larger cattle summer pastures overlapping a higher number of elk telemetry locations. We identified periods when the proximity of elk to specific features (such as mineral blocks, hay land, winter-feeding areas, or water sources) may increase the risk of inter-species transmission. Indirect transmission risk indexes increased with the survival of pathogens in the environment, as the temporal constraint for cattle and elk overlap decreased. Finally, integrating pasture management information substantially influenced the magnitude and temporal patterns of transmission risk indexes, highlighting the importance of collecting detailed livestock management data in the context of assessing the risk of inter-species disease transmission.
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Affiliation(s)
- Mathieu Pruvot
- Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada; Wildlife Conservation Society, Wildlife Health Program, 2300 Southern Boulevard, Bronx, NY 10460, USA.
| | - Marco Musiani
- Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada; Department of Biological Sciences, Faculty of Science, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Mark S Boyce
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta T6G 2E9, Canada
| | - Susan Kutz
- Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
| | - Karin Orsel
- Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
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Appelgren ASC, Saladin V, Richner H, Doligez B, McCoy KD. Gene flow and adaptive potential in a generalist ectoparasite. BMC Evol Biol 2018; 18:99. [PMID: 29921216 PMCID: PMC6009953 DOI: 10.1186/s12862-018-1205-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/30/2018] [Indexed: 12/02/2022] Open
Abstract
Background In host-parasite systems, relative dispersal rates condition genetic novelty within populations and thus their adaptive potential. Knowledge of host and parasite dispersal rates can therefore help us to understand current interaction patterns in wild populations and why these patterns shift over time and space. For generalist parasites however, estimates of dispersal rates depend on both host range and the considered spatial scale. Here, we assess the relative contribution of these factors by studying the population genetic structure of a common avian ectoparasite, the hen flea Ceratophyllus gallinae, exploiting two hosts that are sympatric in our study population, the great tit Parus major and the collared flycatcher Ficedula albicollis. Previous experimental studies have indicated that the hen flea is both locally maladapted to great tit populations and composed of subpopulations specialized on the two host species, suggesting limited parasite dispersal in space and among hosts, and a potential interaction between these two structuring factors. Results C. gallinae fleas were sampled from old nests of the two passerine species in three replicate wood patches and were genotyped at microsatellite markers to assess population genetic structure at different scales (among individuals within a nest, among nests and between host species within a patch and among patches). As expected, significant structure was found at all spatial scales and between host species, supporting the hypothesis of limited dispersal in this parasite. Clustering analyses and estimates of relatedness further suggested that inbreeding regularly occurs within nests. Patterns of isolation by distance within wood patches indicated that flea dispersal likely occurs in a stepwise manner among neighboring nests. From these data, we estimated that gene flow in the hen flea is approximately half that previously described for its great tit hosts. Conclusion Our results fall in line with predictions based on observed patterns of adaptation in this host-parasite system, suggesting that parasite dispersal is limited and impacts its adaptive potential with respect to its hosts. More generally, this study sheds light on the complex interaction between parasite gene flow, local adaptation and host specialization within a single host-parasite system. Electronic supplementary material The online version of this article (10.1186/s12862-018-1205-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anaïs S C Appelgren
- Evolutionary Ecology Laboratory, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, Bern, Switzerland. .,CNRS; Université de Lyon, F-69000, Lyon; Université Lyon 1; Department of Biometry and Evolutionary Biology, LBBE UMR 5558, Bâtiment Gregor Mendel, 43 boulevard du 11 novembre 1918, F-69622, Villeurbanne, France. .,Department of Biometry and Evolutionary Biology, LBBE UMR 5558, Bâtiment Gregor Mendel, Université Lyon 1, 43 boulevard du 11 novembre 1918, F-69622, Villeurbanne, France. .,Maladies Infectieuses & Vecteurs: Ecologie, Génétique, Evolution & Contrôle (MIVEGEC), Université de Montpellier - CNRS - IRD, Centre IRD, 911 avenue, Agropolis, BP 64501, F-34000, Montpellier, France.
| | - Verena Saladin
- Evolutionary Ecology Laboratory, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, Bern, Switzerland
| | - Heinz Richner
- Evolutionary Ecology Laboratory, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, Bern, Switzerland
| | - Blandine Doligez
- CNRS; Université de Lyon, F-69000, Lyon; Université Lyon 1; Department of Biometry and Evolutionary Biology, LBBE UMR 5558, Bâtiment Gregor Mendel, 43 boulevard du 11 novembre 1918, F-69622, Villeurbanne, France.,Department of Biometry and Evolutionary Biology, LBBE UMR 5558, Bâtiment Gregor Mendel, Université Lyon 1, 43 boulevard du 11 novembre 1918, F-69622, Villeurbanne, France.,Department of Ecology and Genetics/Animal Ecology, Evolutionary Biology Centre (EBC), University of Uppsala, Norbyvägen 18D, 752 36, Uppsala, Sweden
| | - Karen D McCoy
- Maladies Infectieuses & Vecteurs: Ecologie, Génétique, Evolution & Contrôle (MIVEGEC), Université de Montpellier - CNRS - IRD, Centre IRD, 911 avenue, Agropolis, BP 64501, F-34000, Montpellier, France
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