Moving endangered species to new locations is often used as part of a conservation strategy, but scientists have found that there is a high risk of spreading disease and parasites in this way.

The new report focuses on freshwater mussels: researchers have thoroughly studied this particular species, but the work applies to all species moved for conservation.

Mussels play an important role in the purification of the waters of many rivers and lakes in the world but are under threat. One of the new ways to conserve them is to move populations that are under threat.

The gonad-eating parasitic worm, Rhipidocotyle campanula, has proven to be very dangerous to mussels. And when they move to other larger groups, the parasite can move to the rest: one infected mussel is enough to spread this parasite.

We need to be much more careful when moving animals to new locations for conservation purposes because the costs can outweigh the benefits.

David Aldridge, Ph.D., Department of Zoology, University of Cambridge, senior author of the report.

In extreme cases, pathogens can lead to a complete collapse of the mussel population.

The report recommends that species only move when absolutely necessary and that quarantine period are used specifically to stop transmission of the most likely transmitted pathogens.