Close spatial overlap between the genetic population boundaries of raccoons and the distribution of the raccoon roundworm in Germany

While raccoons ( Procyon lotor ) cluster into five genetic populations in Germany, the precise spatial extent and degree of overlap of these clusters are unknown. The raccoon roundworm ( Baylisacaris procyonis ), a parasitic nematode that can cause severe disease in humans, is known to occur in central Germany in two of these five populations. Here we confirm a close alignment between the geographic distribution of the roundworm and the spatial extent of the genetic populations of rac- coons in which the parasite occurs. We found little evidence that linear landscape features substan-tially limit gene flow between populations. Given the large amount of genetic admixture at cluster boundaries, the raccoon roundworm is likely to spread to roundworm-free raccoon populations in the future.