Transmissible Venereal Tumour

There are only 2 cancers that are truly infectious, the other in Tasmanian Devils. There are many that are caused by viruses, but with disease, the cancer cells themselves actually infect other dogs. The disease is passed through contact with the genitals either at mating or when dogs just investigate each other. It is most common in the tropics and with stray dog populations. It is cured with chemotherapy.