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333S. Morand et al. (eds.), New Frontiers of Molecular Epidemiology of Infectious Diseases, DOI 10.1007/978-94-007-2114-2_15, © Springer Science+Business Media B.V. 2012
The contributors of this book have explored various facets of molecular epidemiology with major references to population genetics, ecology and evolution.
Molecular epidemiology is now confronted to new challenges in relation to the impacts of global changes on infectious diseases as summarized by Vourc’h et al. (Chap. 13), that favor the spread of drug resistance in parasites of livestock as shown by Silvestre et al. (Chap. 11) or in human pathogens as stressed by Rumy et al. (Chap. 10). Illustrations of these new challenges were given on specific diseases or pathogens such as tuberculosis by Lanotte (Chap. 7), pneumocystosis by Chabe et al. (Chap. 8) or hantaviruses by Blasdell et al. (Chap. 9).
In this final conclusion, we will present four general perspectives emerging from chapters.
15.1 The Challenging Development of New Molecular Tools
New typing technologies, such as high-throughput genomics typing, appear and improve at an accelerating rate. This represents a substantial challenge as emphasized by Hallin et al. (Chap. 2), both by the need to deal with a large amount of molecular
S. Morand (*)Institut des Sciences de l’Evolution, CNRS-IRD-UM2, CC65, Université Montpellier 2, F-34095 Montpellier, France
Cirad AGIRs, F-34398 Montpellier, Francee-mail: [email protected]
J. CabaretINRA, UR1282 Infectiologie Animale et Santé Publique, F-37380 Nouzilly, France e-mail: [email protected]
F. Beaudeau INRA, Oniris, UMR1300 Bio-agression, épidémiologie et analyse de risque en santé animale, BP40706, 44307 Nantes, Francee-mail: [email protected]
Chapter 15Conclusion
Serge Morand, Jacques Cabaret, and François Beaudeau
334 S. Morand et al.
information and by the integration of these analytical tools in public health laboratory. Tibayrenc (Chap. 3) cited pathogen profiling as one of the new strategies emerging from these new tools, which aims at integrating molecular data (genome, transcrip-tome, proteome, metabolome) with clinical and epidemiological data, assisted by geographic information systems (GIS).
15.2 Incorporating Concepts of Population and Evolutionary Genetics
Tibayrenc (Chap. 3), Chevignon et al. (Chap. 4), and Charbonnel and Cosson (Chap. 12) stressed the need to incorporate population genetics’ concepts in molec-ular epidemiology.
Chevignon et al. (Chap. 4) emphasized that population genetics may help, among others, characterize the spatial limits of a parasite population and detect drastic changes in parasite population sizes. Hence, population genetics may help understand the population biology of the infectious agents, which may avoid spurious con-clusions based on the interpretation of easy-made phylogenetic trees (but see also Archie et al. 2009).
Charbonnel and Cosson (Chap. 4) stressed on some gaps that remained to be assessed to understand the evolution of host resistance gene/polymorphism and adaptation, particularly concerning populations in non-equilibrium such as invasive species. They also referred to the concepts and results of immunoecology, a discipline that aims to explain the variability of immune responses in natural populations, that may fruitfully integrate advances in the molecular epidemiology.
15.3 Incorporating Concepts of Theoretical and Population Modeling
Modeling approach may help for various practical purposes, including evaluation of control strategies as emphasized by Ezanno et al. (Chap. 5). A major challenge is to include genetics in epidemiological modeling. However, as stressed by Ezanno et al. (Chap. 5) classical tools of epidemiological modeling may not be relevant and the development of specific tools is then required to integrate evolutionary ecology and epidemiological patterns.
Similarly, Ferdy and Gandon (Chap. 6) advocated that theoretical models on pathogen virulence evolution will gain considerable predictive power if they can be combined to the approaches developed by molecular biologists that relate virulence, transmission and recovery.
From a different perspective, Caron et al. (Chap. 14) advocated the need of integrating theoretical community ecology such as network-based modeling as tool for predicting emergence avenues. They stressed also the need to integrate molecular information and to develop specific tools for manipulating complex networks.
33515 Conclusion
15.4 From Molecular Epidemiology to Phylogeography of Diseases
The development of new phylogenetic methods has allowed the investigation of pathogens’ diversity and their diversification in a spatial context. Phylogeography is a recent science that aims to explain the actual geographic distribution of species and populations by investigating the processes that govern the geographical distributions of lineages within and among closely related species following. Numerous studies have concerned free-living animals and plants, but phylogeographic studies of patho-gens and parasites have only recently grew up (Holmes 2008; Nieberding and Olivieri 2007). New methodologies have been recently proposed implementing Bayesian approach for inference, visualization and hypothesis testing of phylogeographic history (Lemey et al. 2009) or in phylodynamics (Holmes and Grenfell 2009). Phylodynamics intend to associate epidemiological dynamics and evolution of pathogens. It has proven an efficient tool for understanding the dynamics of viral infections (Grenfell et al. 2004) but still remains unexplored for bacterial and para-sitological infections. Incorporation of molecular data into Geographic Information Systems (GIS) has been made easy following the development of specific softwares.
Molecular epidemiology is a rapidly developing science as it relies on technologies (informatics and high-throughput genomics typing among others). We must take care that conceptual issues are not forgotten and it is one aim of the present book.
References
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