Scientists find cases of contagious cancers in shellfish

There is growing evidence of a frightening phenomenon in nature—cancer that is contagious, reports CBC News.

According to a recent news release issued by the Columbia University Medical Center, the cancer known as disseminated neoplasia can spread among members of many bivalve species like clams and mussels.

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This type of transmission in the wild was initially considered to be very rare, with previous cases only seen in Tasmanian devils and dogs.

However, an earlier discovery of related cancer cells in soft-shell clams led scientists to wonder if the disease was also infectious elsewhere, according to the New York Times.

So an international team studied mussels around British Columbia and two marine species—golden carpet shell clams and cockles—around Spain.

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Based on an examination, "in each species, the researchers discovered that the cancers were caused by independent clones of cancer cells that were genetically distinct from their hosts. They also found that in one species, the carpet shell clam, the infectious cancer cells came from a related but distinct species. The researchers concluded that this cancer was due to a case of cross-species transmission."

Nevertheless, the scientists believe the spread only happens among similar species and that humans should not be concerned about this when eating shellfish, notes CBC News.