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"The Evolution of Virulence: A Unifying Link between Parasitology and Ecology" (1995) [18] "Guarding Against the MostDangerous Emerging Pathogens: Insights from Evolutionary Biology" (1996) [ 19 ] "Vaccines as evolutionary tools: The virulence-antigen strategy" (1996) in Concepts in Vaccine Development [ 20 ]
The evolution of virulence in pathogens is a balance between the costs and benefits of virulence to the pathogen. For example, studies of the malaria parasite using rodent [ 3 ] and chicken [ 4 ] models found that there was trade-off between transmission success and virulence as defined by host mortality.
Evolution of Infectious Disease is a 1993 book by the evolutionary biologist Paul W. Ewald. In this book, Ewald contests the traditional view that parasites should evolve toward benign coexistence with their hosts. He draws on various studies that contradict this dogma and asserts his theory based on fundamental evolutionary principles.
Virulence is a pathogen's or microorganism's ability to cause damage to a host. In most cases, especially in animal systems, virulence refers to the degree of damage caused by a microbe to its host. [1] The pathogenicity of an organism—its ability to cause disease—is determined by its virulence factors.
Viral evolution is a subfield of evolutionary biology and virology that is specifically concerned with the evolution of viruses. [ 1 ] [ 2 ] Viruses have short generation times, and many—in particular RNA viruses —have relatively high mutation rates (on the order of one point mutation or more per genome per round of replication).
A successful pathogen needs to spread to at least one other host, and lower virulence can result in higher transmission rates under some circumstances. Likewise, genetic resistance against the virus can develop in a host population over time. [2] [29] An example of the evolution of virulence in emerging virus is the case of myxomatosis in ...
A higher virulence would increase the potential for the production of more offspring, but a higher spore load would affect the host's lifespan and therefore the transmission rate. This trade-off is supported by coevolutionary experiments, which revealed the decrease of virulence, a constant transmission potential and an increase in the host's ...
When developing vaccines for viruses, the emphasis is on attenuating the virus, or decreasing its virulence, in a given host. Sometimes it is useful to employ serial passage to increase the virulence of a virus. Usually, when serial passage is performed in a species, the result is a virus that is more virulent to that species. [5]