Phylogenetic concordance analysis shows an emerging pathogen is novel and endemic.
Distinguishing whether pathogens are novel or endemic is critical for controlling emerging infectious diseases, an increasing threat to wildlife and human health. To test the endemic vs. novel pathogen hypothesis, we present a unique analysis of intraspecific host-pathogen phylogenetic concordance of tiger salamanders and an emerging Ranavirus throughout Western North America. There is significant non-concordance of host and virus gene trees, suggesting pathogen novelty. However, non-concordance has likely resulted from virus introductions by human movement of infected salamanders. When human-associated viral introductions are excluded, host and virus gene trees are identical, strongly supporting coevolution and endemism. A laboratory experiment showed an introduced virus strain is significantly more virulent than endemic strains, likely due to artificial selection for high virulence. Thus, our analysis of intraspecific phylogenetic concordance revealed that human introduction of viruses is the mechanism underlying tree non-concordance and possibly disease emergence via artificial selection.
Storfer
Andrew
A
School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA. astorfer@wsu.edu
Alfaro
Michael E
ME
Ridenhour
Benjamin J
BJ
Jancovich
James K
JK
Mech
Stephen G
SG
Parris
Matthew J
MJ
Collins
James P
JP
D000818:Animals; D000835:Animals, Wild; D005075:Biological Evolution; D021821:Communicable Diseases, Emerging / Q000635:transmission / Q000662:veterinary / Q000821:virology; D003247:Conservation of Natural Resources; D004266:DNA Virus Infections / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D003710:Demography; D006801:Humans; D010802:Phylogeny; D011634:Public Health; D017995:Ranavirus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D014481:United States; D014562:Caudata / Q000821:virology*; D014774:Virulence / Q000235:genetics