Invasive rusty crayfish (Faxonius rusticus) populations in North America are infected with the crayfish plague disease agent (Aphanomyces astaci)

AbstractThe American rusty crayfish, Faxonius rusticus, is an invasive species in parts of North America where it displaces native crayfish species. In Europe, various invasive North American crayfish species are carriers of the crayfish plague disease agent Aphanomyces astaci that causes devastating population declines of European crayfish. Little is known about either the presence or the influence of A. astaci in North America where it originates. Here, we attempted to isolate A. astaci from North American F. rusticus for the first time and compare it to the strains detected in Europe. We tested the infection status of 84 F. rusticus samples from 10 different locations in the midwestern United States that are outside of the F. rusticus native distribution range. We used quantitative real-time PCR (qPCR) to assess the infection status in each individual, and we determined the mitochondrial haplotypes and multilocus microsatellite genotypes when it was possible. We detected A. astaci DNA in 9 individuals ...