Deep in This Lake, a Contagious Cancer Is Spreading
Transmissible tumors have been reported in a handful of animal species, but never before among fish. Is it possible in humans?
For over a decade, something strange has been happening in a lake straddling the border of Vermont and Quebec.
Lake Memphremagog is home to brown bullhead catfish , and in 2012, anglers began noticing that some of them were covered in velvety black growths. Wildlife biologists eventually determined that the fish had skin cancer.
So-called melanomas are exceedingly rare in catfish, but more than a third of the bullheads carried them. Now, researchers think they know why: A contagious form of cancer is spreading through the lake, they reported on Wednesday .
The outbreak started with a single catfish, the scientists believe. It developed a tumor, which shed cancer cells into the water. Those cells invaded other catfish, in effect beginning a plague.
Researchers have found contagious tumors in only a tiny, seemingly random collection of species: dogs , Tasmanian devils and a few kinds of clams and other shellfish. But those discoveries have been enough to raise a host of provocative questions.