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United States Department of Agriculture

Agricultural Research Service

Title: Phylogeny, Ecological Fitting and Lung Flukes: Helping Solve the Problem of Emerging Infectious Diseases

Authors
item Brooks, Daniel - U TORONTO, CANADA
item Mclennan, Deborah - U TORONTO, CANADA
item Leon-Regagnon, Virginia - INST.BIOL. MEXICO
item Hoberg, Eric

Submitted to: Revista Mexicana de Biodiversidad
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 20, 2006
Publication Date: December 15, 2006
Citation: Brooks,D.R., Mclennan,D.A., Leon-Regagnon,V., Hoberg,E.P. 2006. Phylogeny, ecological fitting and lung flukes: helping solve the problem of emerging infectious diseases. Revista Mexicana de Biodiversidad. 77:225-233.

Interpretive Summary: Invasive species and emergent pathogens, parasites and diseases represent serious threats to our natural ecosystems and managed agricultural lands and livestock. The behavior of potentially invasive species in new habitats or associations with hosts can only be understood or predicted based on a framework from ecological and evolutionary theory. We explore some current ideas about determinants of distribution for pathogens and hosts and develop new insights about the critical importance of historical and phylogenetic data for hosts and parasites in limiting the spread and impacts of exotic and invasive species. Traditional wisdom tells us that pathogens with multi-host life cycles are unlikely to move with their definitive hosts because their transmission requirements are so specialized. The phenomenon of ecological fitting, however, can promote the rapid spread of introduced pathogens with complex lifecycles if the resource required at each stage of the lifecycle is both phylogenetically conservative (distributed among numerous species) and geographically widespread. The external appearance of life cycle complexity is not, therefore, on its own, a reliable measure of the potential for an organism to become an emerging infectious disease. We apply this concept to explain a potential enigma, the presence of a lung fluke, Haematoloechus floedae, endemic to North American bullfrogs, in Costa Rican leopard frogs, even though there are no bullfrogs extant in the country today, and none ever occurred where the parasite has been discovered. The integration of ecological and life history information within a phylogenetic framework can help biologists move from attempts to manage emerging infectious disease outbreaks to the ability to predict and thus circumvent the outbreak in the first place.

Technical Abstract: Traditional wisdom tells us that pathogens with multi-host life cycles are unlikely to move with their definitive hosts because their transmission requirements are so specialized. The phenomenon of ecological fitting, however, can promote the rapid spread of introduced pathogens with complex lifecycles if the resource required at each stage of the lifecycle is both phylogenetically conservative (distributed among numerous species) and geographically widespread. The external appearance of life cycle complexity is not, therefore, on its own, a reliable measure of the potential for an organism to become an emerging infectious disease. We apply this concept to explain a potential enigma, the presence of a lung fluke, Haematoloechus floedae, endemic to North American bullfrogs, in Costa Rican leopard frogs, even though there are no bullfrogs extant in the country today, and none ever occurred where the parasite has been discovered. We then discuss how the integration of ecological and life history information within a phylogenetic framework can help biologists move from attempts to manage emerging infectious disease outbreaks to the ability to predict and thus circumvent the outbreak in the first place.

Last Modified: 9/10/2014
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