Biomaterial Database

Life histories of pathogen populations. 2009

Robert L Perlman

Department of Pediatrics, The University of Chicago, 5841 S. Maryland Ave., MC 5058, Chicago, IL 60637, USA. addresses: r-perlman@uchicago.edu

The populations of pathogens in individual hosts have many of the characteristics of multicellular organisms, or individuals. These populations go through a life cycle within a host and they reproduce by founding daughter populations in new hosts. Natural selection shapes the life history characteristics of pathogen populations--life expectancy, trade-offs in the allocation of resources between growth, survival, and fecundity, and aging--in ways that maximize the reproductive fitness of the pathogens. In turn, these life history characteristics shape the natural histories of infectious diseases. Transmissibility and virulence may be thought of as properties of pathogen populations rather than as properties of the constituent microorganisms within these populations. The poor correlation of virulence with pathogen fitness is a major obstacle to the development of a theory of virulence. Consideration of the life histories of pathogen populations complements the traditional epidemiological focus on host populations and provides a valuable perspective for understanding human infectious diseases.

UI	MeSH Term	Description	Entries
D008018	Life Cycle Stages	The continuous sequence of changes undergone by living organisms during the post-embryonic developmental process, such as metamorphosis in insects and amphibians. This includes the developmental stages of apicomplexans such as the malarial parasite, PLASMODIUM FALCIPARUM.	Life Cycle,Life History Stages,Cycle, Life,Cycles, Life,History Stage, Life,History Stages, Life,Life Cycle Stage,Life Cycles,Life History Stage,Stage, Life Cycle,Stage, Life History,Stages, Life Cycle,Stages, Life History
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D010271	Parasites	Invertebrate organisms that live on or in another organism (the host), and benefit at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.	Parasite
D011157	Population Dynamics	The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.	Malthusianism,Neomalthusianism,Demographic Aging,Demographic Transition,Optimum Population,Population Decrease,Population Pressure,Population Replacement,Population Theory,Residential Mobility,Rural-Urban Migration,Stable Population,Stationary Population,Aging, Demographic,Decrease, Population,Decreases, Population,Demographic Transitions,Dynamics, Population,Migration, Rural-Urban,Migrations, Rural-Urban,Mobilities, Residential,Mobility, Residential,Optimum Populations,Population Decreases,Population Pressures,Population Replacements,Population Theories,Population, Optimum,Population, Stable,Population, Stationary,Populations, Optimum,Populations, Stable,Populations, Stationary,Pressure, Population,Pressures, Population,Replacement, Population,Replacements, Population,Residential Mobilities,Rural Urban Migration,Rural-Urban Migrations,Stable Populations,Stationary Populations,Theories, Population,Theory, Population,Transition, Demographic,Transitions, Demographic
D003141	Communicable Diseases	An illness caused by an infectious agent or its toxins that occurs through the direct or indirect transmission of the infectious agent or its products from an infected individual or via an animal, vector or the inanimate environment to a susceptible animal or human host.	Infectious Diseases,Communicable Disease,Disease, Communicable,Disease, Infectious,Diseases, Communicable,Diseases, Infectious,Infectious Disease
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001419	Bacteria	One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.	Eubacteria
D014774	Virulence	The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.	Pathogenicity