A transmissible melanoma-type cancer has been discovered in fish, the fourth known contagious tumor among animals
Since 2012, a population of brown catfish in a lake between Canada and the United States has been observed to have a very high incidence of melanoma, a tumor generally associated with sun exposure. Now, a team from Vermont (USA) has discovered that, in this case, it is a transmissible cancer that spreads from fish to fish like a parasite. This finding represents the fourth known transmissible cancer in the animal kingdom and the first in any species of fish or freshwater animal; previous examples include facial tumor disease in Tasmanian devils, a venereal tumor in dogs, and leukemia-like transmissible diseases in clams, mussels, and other bivalve mollusks. The researchers published their results in Nature and emphasize that the disease poses no known risk to humans.