This theory posits that pathogen virulence traits can evolve if these traits are directly or indirectly linked to pathogen fitness (Anderson and May 1982 Bull 1994 Ewald 1994 Read 1994 Ebert and Herre 1996 Frank 1996 Alizon et al. Our discussion is grounded in the extensive body of theory that deals with evolution of virulence.
We survey various aquaculture practices that could lead to those conditions. 2010), aquaculture, like all farming industries, can create conditions that may favor the development of highly virulent pathogens. As others have pointed out (Murray and Peeler 2005 Day and Prince 2007 Mennerat et al. We define “virulence” as the deleterious health effects of pathogen infection on a host. Here, we consider how current management practices may make aquaculture vulnerable to the evolutionary emergence of high virulence pathogen strains. Continued pathogen emergence is unavoidable as aquaculture intensifies. Strong evidence, nevertheless, suggests that pathogen evolution, including evolution of virulence, is also playing a role in the emergence of some diseases in aquaculture (Walker and Winton 2010). Given the rapid growth and dynamic nature of aquaculture worldwide (Food and Agricultural Organization of the United Nations 2014), it seems likely that even without evolution, epidemiological changes will lead to increases in the disease burden of aquaculture. In aquaculture, infectious disease is already a substantial cause of economic loss (Meyer 1991). The emergence of highly virulent pathogens has devastated many food production industries, including examples such as Irish potato culture in the mid-1800s and Taiwanese prawn culture in the 1980s (Bourke 19 Strange and Scott 2005).
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