Scientists have discovered infectious cancers in some clams, mollusks and bivalves that possibly jump from one animal to the next. Shellfish are the sixth organism found to have contagious types cancers, others include Tasmanian devils and dogs.
Researchers from Columbia University in New York City made the discovery while studying leukemia in a clam, the Mya arenaria, which lives in tidal mudflats across the Atlantic coastline. Some tumor cells collected from samples had the same genome sequence, leading researchers to believe that a clone of the cancer spread between animals, and possibly even species.
How the cancer spreads is not clear. One theory is that the cancer simply finds a new host when their old one dies. The cells may also be consumed when the clam filter-feeds and the cancer cells may excreted through clam feces.
The cancer does not appear to be dangerous to humans.