A new insight into genetic structure of Danube and Italian foci of fascioloidosis.

Human induced translocation and introduction of species have reshaped parasite fauna on a global scale. The introduction of the large American liver fluke Fascioloides magna from North America to Europe is an example of an invasive alien parasite causing significant ecological and economic damage. Recent genetic studies have shown that F. magna was introduced to Europe on multiple occasions forming three permanent foci of infection. This study primarily focuses on the poorly researched genetic structuring of F. magna flukes originating from Croatia and Serbia. Additional samples from USA and Italy are also included, thereby providing novel insights into F. magna's biogeography. Partial cox1 and nad1 genes were amplified from 216 F. magna flukes extracted from red deer, roe deer, fallow deer, white-tailed deer and wild boar. Seven cox1 and nine nad1 haplotypes were identified, of which two cox1 and four nad1 haplotypes have not been not previously found. Our analysis has expanded the knowledge about possible sources of F. magna introduction to Europe, by identifying a cox1 haplotype shared by flukes from the north-eastern parts of the USA and Italy and another cox1 haplotype shared by flukes also from north eastern parts of the USA and the Danube floodplains.

Infestation of wild bay scallops Argopecten irradians on Nantucket Island by the shell-boring polychaete Polydora neocaeca.

Shell-boring polychaete worms can severely impact shellfish aquaculture by reducing growth rates and compromising tissue quality of their molluscan hosts. In this study we report the first known instance of shell-infestation of commercially important scallops on Nantucket Island by the cryptogenic polydorid Polydora neocaeca. Additional analyses indicate a high level of genetic connectivity between worms from Nantucket Island and the US mainland, forming a distinct haploclade which is genetically isolated from populations from South Africa and Japan. While transportation of infected seed could have introduced the worm to Nantucket, limited sampling and the paucity of sequence data available makes it impossible to definitely determine its origins.