WEIRD: Cancer Can Spread To Dogs As A Parasite

A strange form of cancer is being transmitted as an infectious agent among the world's dogs, without help from viruses or bacteria, a research team in England has found.

The discovery, reported in the journal Cell, shows how a single cancer cell can become a parasite, grow and then spread worldwide in susceptible animals.

Fortunately, even though the tumours grow aggressively at first, they eventually shrink and then succumb to the host dog's immune system. Remarkably, after the cancer has disappeared, the dogs have gained protective immunity, which blocks further infection by the cancer cells. The dogs' blood also can be used to vaccinate other dogs and block infection.