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Ferraguti M. Mosquito species identity matters: unraveling the complex interplay in vector-borne diseases. Infect Dis (Lond) 2024:1-12. [PMID: 38795138 DOI: 10.1080/23744235.2024.2357624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 05/14/2024] [Indexed: 05/27/2024] Open
Abstract
BACKGROUND Research on vector-borne diseases has traditionally centred on a limited number of vertebrate hosts and their associated pathogens, often neglecting the broader array of vectors within communities. Mosquitoes, with their vast species diversity, hold a central role in disease transmission, yet their capacity to transmit specific pathogens varies considerably among species. Quantitative modelling of mosquito-borne diseases is essential for understanding transmission dynamics and requires the necessity of incorporating the identity of vector species into these models. Consequently, understanding the role of different species of mosquitoes in modelling vector-borne diseases is crucial for comprehending pathogen amplification and spill-over into humans. This comprehensive overview highlights the importance of considering mosquito identity and emphasises the essential need for targeted research efforts to gain a complete understanding of vector-pathogen specificity. METHODS Leveraging the recently published book, 'Mosquitoes of the World', I identified 19 target mosquito species in Europe, highlighting the diverse transmission patterns exhibited by different vector species and the presence of 135 medically important pathogens. RESULTS The review delves into the complexities of vector-pathogen interactions, with a focus on specialist and generalist strategies. Furthermore, I discuss the importance of using appropriate diversity indices and the challenges associated with the identification of correct indices. CONCLUSIONS Given that the diversity and relative abundance of key species within a community significantly impact disease risk, comprehending the implications of mosquito diversity in pathogen transmission at a fine scale is crucial for advancing the management and surveillance of mosquito-borne diseases.
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Affiliation(s)
- Martina Ferraguti
- Department of Conservation Biology and Global Change, Estación Biológica de Doñana (EBD), CSIC, Seville, Spain
- Department of Theoretical and Computational Ecology (TCE), Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, the Netherlands
- CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
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An R, Liu Y, Pan C, Da Z, Zhang P, Qiao N, Zhao F, Ba S. Water quality determines protist taxonomic and functional group composition in a high-altitude wetland of international importance. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 880:163308. [PMID: 37028668 DOI: 10.1016/j.scitotenv.2023.163308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/26/2023] [Accepted: 04/01/2023] [Indexed: 05/27/2023]
Abstract
Alpine wetland is a natural laboratory for studying the Earth's third polar ecosphere. Protist communities are key components of wetland ecosystems which are extremely vulnerable to environmental change. It is of great importance to study the protist community in relation to environment, which might be the key to understand the ecosystem of the alpine wetlands under global change. In this study, we investigated the composition of protist communities across the Mitika Wetland, a unique alpine wetland hosting tremendous endemic diversity. Using 18S rRNA gene high-throughput sequencing, we evaluated how protist taxonomic and functional group composition is structured by seasonal climate and environmental variation. We found a high relative abundance of Ochrophyta, Ciliophora, and Cryptophyta, each of which showcased a unique spatial pattern in the wet and dry seasons. The proportion of consumers, parasites and phototrophs groups were stable among the functional zones and also between the seasons, with consumers dominating communities in terms of richness, while phototrophic taxa dominated in terms of relative abundance. Protist and each functional group were rather regulated by deterministic than stochastic processes, with water quality having a strong control on communities. Salinity and pH were the most important environmental factors at shaping protistan community. The protist co-occurrence network dominated by the positive edge indicating the communities resisted extreme environmental conditions through close cooperation, and more consumers were determined as the keystones in wet season and more phototrophic taxa in dry season. Our results provided the baseline of the protist taxonomic and functional group composition in the highest wetland, and highlighted environmental selections drive protist distribution, implying the alpine wetland ecosystem are sensitive to climate changes and human activities.
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Affiliation(s)
- Ruizhi An
- Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China
| | - Yang Liu
- Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China
| | - Chengmei Pan
- Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China
| | - Zhen Da
- Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China
| | - Peng Zhang
- Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China
| | - Nanqian Qiao
- Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China
| | - Feng Zhao
- Laboratory of Marine Organism Taxonomy and Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Sang Ba
- Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China.
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Herczeg D, Ujszegi J, Kásler A, Holly D, Hettyey A. Host-multiparasite interactions in amphibians: a review. Parasit Vectors 2021; 14:296. [PMID: 34082796 PMCID: PMC8173923 DOI: 10.1186/s13071-021-04796-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/20/2021] [Indexed: 01/15/2023] Open
Abstract
Parasites, including viruses, bacteria, fungi, protists, helminths, and arthropods, are ubiquitous in the animal kingdom. Consequently, hosts are frequently infected with more than one parasite species simultaneously. The assessment of such co-infections is of fundamental importance for disease ecology, but relevant studies involving non-domesticated animals have remained scarce. Many amphibians are in decline, and they generally have a highly diverse parasitic fauna. Here we review the literature reporting on field surveys, veterinary case studies, and laboratory experiments on co-infections in amphibians, and we summarize what is known about within-host interactions among parasites, which environmental and intrinsic factors influence the outcomes of these interactions, and what effects co-infections have on hosts. The available literature is piecemeal, and patterns are highly diverse, so that identifying general trends that would fit most host–multiparasite systems in amphibians is difficult. Several examples of additive, antagonistic, neutral, and synergistic effects among different parasites are known, but whether members of some higher taxa usually outcompete and override the effects of others remains unclear. The arrival order of different parasites and the time lag between exposures appear in many cases to fundamentally shape competition and disease progression. The first parasite to arrive can gain a marked reproductive advantage or induce cross-reaction immunity, but by disrupting the skin and associated defences (i.e., skin secretions, skin microbiome) and by immunosuppression, it can also pave the way for subsequent infections. Although there are exceptions, detrimental effects to the host are generally aggravated with increasing numbers of co-infecting parasite species. Finally, because amphibians are ectothermic animals, temperature appears to be the most critical environmental factor that affects co-infections, partly via its influence on amphibian immune function, partly due to its direct effect on the survival and growth of parasites. Besides their importance for our understanding of ecological patterns and processes, detailed knowledge about co-infections is also crucial for the design and implementation of effective wildlife disease management, so that studies concentrating on the identified gaps in our understanding represent rewarding research avenues. ![]()
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Affiliation(s)
- Dávid Herczeg
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.
| | - János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary
| | - Andrea Kásler
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Dóra Holly
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Ecology, Institute for Biology, University of Veterinary Medicine, Rottenbiller utca 50, Budapest, 1077, Hungary
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Abstract
AbstractCompetition between parasite species or genotypes can play an important role in the establishment of parasites in new host populations. Here, we investigate a mechanism by which a rare parasite is unable to establish itself in a host population if a common resident parasite is already present (a ‘priority effect’). We develop a simple epidemiological model and show that a rare parasite genotype is unable to invade if coinfecting parasite genotypes inhibit each other's transmission more than expected from simple resource partitioning. This is because a rare parasite is more likely to be in multiply-infected hosts than the common genotype, and hence more likely to pay the cost of reduced transmission. Experiments competing interfering clones of bacteriophage infecting a bacterium support the model prediction that the clones are unable to invade each other from rare. We briefly discuss the implications of these results for host-parasite ecology and (co)evolution.
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Body size and meta-community structure: the allometric scaling of parasitic worm communities in their mammalian hosts. Parasitology 2016; 143:880-893. [PMID: 27001526 DOI: 10.1017/s0031182015001444] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this paper we derive from first principles the expected body sizes of the parasite communities that can coexist in a mammal of given body size. We use a mixture of mathematical models and known allometric relationships to examine whether host and parasite life histories constrain the diversity of parasite species that can coexist in the population of any host species. The model consists of one differential equation for each parasite species and a single density-dependent nonlinear equation for the affected host under the assumption of exploitation competition. We derive threshold conditions for the coexistence and competitive exclusion of parasite species using invasion criteria and stability analysis of the resulting equilibria. These results are then used to evaluate the range of parasites species that can invade and establish in a target host and identify the 'optimal' size of a parasite species for a host of a given body size; 'optimal' is defined as the body size of a parasite species that cannot be outcompeted by any other parasite species. The expected distributions of parasites body sizes in hosts of different sizes are then compared with those observed in empirical studies. Our analysis predicts the relative abundance of parasites of different size that establish in the host and suggests that increasing the ratio of parasite body size to host body size above a minimum threshold increases the persistence of the parasite population.
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Yakob L, Williams GM, Gray DJ, Halton K, Solon JA, Clements ACA. Slaving and release in co-infection control. Parasit Vectors 2013; 6:157. [PMID: 23721567 PMCID: PMC3691829 DOI: 10.1186/1756-3305-6-157] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/23/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Animal and human infection with multiple parasite species is the norm rather than the exception, and empirical studies and animal models have provided evidence for a diverse range of interactions among parasites. We demonstrate how an optimal control strategy should be tailored to the pathogen community and tempered by species-level knowledge of drug sensitivity with use of a simple epidemiological model of gastro-intestinal nematodes. METHODS We construct a fully mechanistic model of macroparasite co-infection and use it to explore a range of control scenarios involving chemotherapy as well as improvements to sanitation. RESULTS Scenarios are presented whereby control not only releases a more resistant parasite from antagonistic interactions, but risks increasing co-infection rates, exacerbating the burden of disease. In contrast, synergisms between species result in their becoming epidemiologically slaved within hosts, presenting a novel opportunity for controlling drug resistant parasites by targeting co-circulating species. CONCLUSIONS Understanding the effects on control of multi-parasite species interactions, and vice versa, is of increasing urgency in the advent of integrated mass intervention programmes.
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Affiliation(s)
- Laith Yakob
- Infectious Disease Epidemiology Unit, School of Population Health, University of Queensland, Herston, Brisbane, QLD 4006, Australia.
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7
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Modelling multi-species parasite transmission. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010. [PMID: 20632528 DOI: 10.1007/978-1-4419-6064-1_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Some models are presented for the dynamics of a host population with two parasite species. The models differ in two main aspects: whether they include direct competition among parasites and whether the analysis is based on some approximation and which one. If the analysis is not constrained by a priori assumptions about parasite distributions, it is found that species coexistence is very unlikely without some kind of direct competition among parasites; on the other hand, coexistence generally occurs when inter-specific competition is lower than intraspecific, similarly to standard theory for free-living species. If hosts differ in their predisposition to infection, but not in an identical way towards the two parasite species, then species coexistence becomes feasible even if inter-specific competition is as strong as intraspecific; in this case, coexistence becomes easier as the variance in predisposition increases. These models do not yield universal predictions for patterns of parasite distributions; an analysis of the mechanisms of interaction in each specific system is necessary for that.
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Tesana S, Srisawangwong T, Sithithaworn P, Laha T. Angiostrongylus cantonensis: Experimental study on the susceptibility of apple snails, Pomacea canaliculata compared to Pila polita. Exp Parasitol 2008; 118:531-5. [DOI: 10.1016/j.exppara.2007.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 11/07/2007] [Accepted: 11/12/2007] [Indexed: 11/15/2022]
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9
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Worms and germs: the population dynamic consequences of microparasite-macroparasite co-infection. Parasitology 2007; 135:1545-60. [DOI: 10.1017/s003118200700025x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYHosts are typically simultaneously co-infected by a variety of microparasites (e.g. viruses and bacteria) and macroparasites (e.g. parasitic helminths). However, the population dynamical consequences of such co-infections and the implications for the effectiveness of imposed control programmes have yet to be fully realised. Mathematical models may provide an important framework for exploring such issues and have proved invaluable in helping to understand the factors affecting the epidemiology of single parasitic infections. Here the first population dynamic model of microparasite-macroparasite co-infection is presented and used to explore how co-infection alters the predictions of the existing single-species models. It is shown that incorporating an additional parasite species into existing models can greatly stabilise them, due to the combined density-dependent impacts on the host population, but co-infection can also restrict the region of parameter space where each species could persist alone. Overall it is concluded that the dynamic feedback between host, microparasite and macroparasite means that it is difficult to appreciate the factors affecting parasite persistence and predict the effectiveness of control by just studying one component in isolation.
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Abstract
The concept of the basic reproduction number (R0) occupies a central place in epidemic theory. The value of R0 determines the proportion of the population that becomes infected over the course of a (modelled) epidemic. In many models, (i) an endemic infection can persist only if R0>1, (ii) the value of R0 provides a direct measure of the control effort required to eliminate the infection, and (iii) pathogens evolve to maximize their value of R0. These three statements are not universally true. In this paper, some exceptions to them are discussed, based on the extensions of the SIR model.
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Affiliation(s)
- M G Roberts
- Centre for Mathematical Biology, Institute of Information and Mathematical Sciences, Massey University, Private Bag 102 904, North Shore Mail Centre, Auckland, New Zealand.
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11
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Abstract
Pathogens that can infect multiple host species will have different dynamics than pathogens that are restricted to a single species of host. This article examines the conditions for establishment and long-term population dynamic behavior of pathogens that infect multiple species of hosts. The article attempts to address three major questions in this area: First, under which conditions will increases in the diversity of host species buffer infectious disease outbreaks, and under which conditions will host diversity amplify disease outbreaks? Second, under what conditions is it possible to control an infectious agent by focusing control against only one host species? Third, what role does host species diversity play in maintaining pathogen persistence? The answers to these questions supply some important general insights into the role that biodiversity plays in buffering humans and other species against new and emerging pathogens.
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Affiliation(s)
- Andrew Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544-1003, USA.
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12
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Bottomley C, Isham V, Basáñez MG. Population biology of multispecies helminth infection: Competition and coexistence. J Theor Biol 2007; 244:81-95. [DOI: 10.1016/j.jtbi.2006.07.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2006] [Revised: 06/09/2006] [Accepted: 07/19/2006] [Indexed: 11/25/2022]
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Jackson JA, Pleass RJ, Cable J, Bradley JE, Tinsley RC. Heterogeneous interspecific interactions in a host-parasite system. Int J Parasitol 2006; 36:1341-9. [PMID: 16934815 DOI: 10.1016/j.ijpara.2006.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 07/11/2006] [Accepted: 07/13/2006] [Indexed: 11/27/2022]
Abstract
Macroparasites of vertebrates usually occur in multi-species communities, producing infections whose outcome in individual hosts or host populations may depend on the dynamics of interactions amongst the different component species. Within a single co-infection, competition can occur between conspecific and heterospecific parasite individuals, either directly or via the host's physiological and immune responses. We studied a natural single-host, multi-parasite model infection system (polystomes in the anuran Xenopus laevis victorianus) in which the parasite species show total interspecific competitive exclusion as adults in host individuals. Multi-species infection experiments indicated that competitive outcomes were dependent on infection species composition and strongly influenced by the intraspecific genetic identity of the interacting organisms. Our results also demonstrate the special importance of temporal heterogeneity (the sequence of infection by different species) in competition and co-existence between parasite species and predict that developmental plasticity in inferior competitors, and the induction of species-specific host resistance, will partition the within-host-individual habitat over time. We emphasise that such local (within-host) context-dependent processes are likely to be a fundamental determinant of population dynamics in multi-species parasite assemblages.
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Affiliation(s)
- J A Jackson
- School of Biology, University of Nottingham, Nottingham NG7 2RD, UK.
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Bottomley C, Isham V, Basáñez MG. Population biology of multispecies helminth infection: interspecific interactions and parasite distribution. Parasitology 2005; 131:417-33. [PMID: 16178364 DOI: 10.1017/s0031182005007791] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Despite evidence for the existence of interspecific interactions between helminth species, there has been no theoretical exploration of their effect on the distribution of the parasite species in a host population. We use a deterministic model for the accumulation and loss of adult worms of 2 interacting helminth species to motivate an individual-based stochastic model. The mean worm burden and variance[ratio ]mean ratio (VMR) of each species, and the correlation between the two species are used to describe the distribution within different host age classes. We find that interspecific interactions can produce convex age-intensity profiles and will impact the level of aggregation (as measured by the VMR). In the absence of correlated exposure, the correlation in older age classes may be close to zero when either intra- or interspecific synergistic effects are strong. We therefore suggest examining the correlation between species in young hosts as a possible means of identifying interspecific interaction. The presence of correlation between the rates of exposure makes the interpretation of correlations between species more difficult. Finally we show that in the absence of interaction, strong positive correlations are generated by averaging across most age classes.
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Affiliation(s)
- C Bottomley
- Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), Wolfson House, 4 Stephenson Way, London NW1 2HE.
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Chalvet-Monfray K, Sabatier P, Chauve C, Zenner L. A Mathematical Model of the Population Dynamics of Heterakis Gallinarum in Turkeys (Meleagridis Gallopavo). Poult Sci 2004; 83:1629-35. [PMID: 15510545 DOI: 10.1093/ps/83.10.1629] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Heterakis gallinarum is a relatively nonpathogenic organism, but it is important as the transport host for the pathogenic protozoan Histomonas meleagridis. A mathematical model was developed to describe the population dynamics of Heterakis gallinarum in a turkey flock to study its kinetics in a number of hosts. The model includes quantitative (parasite burden) and qualitative (number of hosts without mature parasite) descriptions of these dynamics. To understand the role of Heterakis as a transport host, the various elements that delay the beginning of development of the parasite population (e.g., necessary delay of larval stage, the probability of having a male and female in the same host) were taken into account. From published data, the negative binomial distribution parameter k = 0.24, which described the aggregated distribution of the Heterakis among the hosts, was calculated. The sensibility study showed that when the k parameter decreased (i.e., when the population was more aggregated), infestation increased quantitatively (mean parasite burden increased) but not qualitatively (the number of host without mature parasite increased). The model demonstrated that the population dynamics of Heterakis takes time; for instance, with an aggregated population of Heterakis at d 90, the host is mainly free of adult parasite. These results may be used in the future to test the role of Heterakis in the spread of Histomonas.
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Affiliation(s)
- K Chalvet-Monfray
- Unité Environnement et Prévision de la Santé des Populations, Equipe BioMathématiques et Epidémiologie (USC INRA/ENVL), France.
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Affiliation(s)
- Andy Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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17
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Affiliation(s)
- John Janovy
- School of Biological Sciences, University of Nebraska-Lincoln, 68588-0118, USA.
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19
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Perlman S, Jaenike J. Competitive interactions and persistence of two nematode species that parasitize Drosophila recens. Ecol Lett 2001. [DOI: 10.1046/j.1461-0248.2001.00270.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Coexistence of macroparasites is studied by extending the infinite-dimensional model considered by Anderson and May (1978, J. Anim. Ecol. 47, 219-247, 249-267) to several species of parasites that are assumed to interact only by causing the death of a common host. An exact invadability condition is found for this model. By studying when mutual invasibility is possible, the region where two parasite species can coexist is found. The result is that, if there is a trade-off between virulence and transmissibility, then coexistence of two species of parasites is possible, but only when the parameters of the model fall into a very narrow parameter region. If, on the other hand, one parasite is more virulent and less transmissible, then it will be competitively excluded. This latter result, though expected in terms of competition theory, is in contrast with what found in the approximate models so far used for studying interacting macroparasites. The effect of parasite aggregation on coexistence is studied by considering two modifications of the basic model (clumped infections and host population heterogeneity in predisposition to infections) that allow for higher aggregation. It appears that the width of the coexistence region is insensitive to these modifications.
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Affiliation(s)
- A Pugliese
- Dipartimento di Matematica, Università degli Studi di Trento, Via Sommarive 14, Povo (Trento), 38050, Italy.
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21
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Abstract
Mathematical models have been used to describe the population dynamics of a wide range of host-parasite interactions. Mick Roberts here discusses mathematical models for the dynamics of helminth endoparasites of non-human mammalian hosts, paying particular attention to the density-dependent factors that regulate the parasite populations, and the interaction between parasite and wild or feral animal host populations.
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Affiliation(s)
- M G Roberts
- AgResearch, Wallaceville Animal Research Centre, Upper Hutt, New Zealand.
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