A rare cancer called ‘Canine Transmissible Venereal Tumor’ – or CTVT – can jump between the creatures when they sniff each other’s intimate areas. Living cancer cells are physically “transplanted” from one animal to another. Dogs often smell each other because it tells them about the identity, sex, health, mood, diet of the other animal and confirms whether they have met before, but it can carry disease. CTVT is usually spread during intercourse, but sometimes the cancer can affect other areas such as the nose, mouth and skin.
Most facial cancers in male dogs
To find out what was causing the oddly located tumors, researchers looked at a database and found that 84 percent of facial cancers were in male dogs. In contrast, cases of genital CTVT occur in approximately equal numbers of male and female dogs. “We found that a very significant proportion of the nose or mouth tumors of the contagious canine cancer were in male dogs,” said Dr Andrea Strakova at the University of Cambridge’s department of veterinary medicine, the first author of the paper. “We think this is because male dogs may prefer to smell or lick female genitalia, compared to the other way around. “Female genital tumors may also be more accessible to sniffing and licking, compared to male genital tumors.”
Increase in cases linked to animal imports
CTVT is now found in dog populations worldwide and is the oldest and most prolific cancer lineage known in nature. Although not common in Britain, cases have been increasing over the past decade, linked to the importation of animals from abroad. The disease occurs worldwide, but is mainly associated with countries with free-roaming dog populations. The most common symptoms of oropharyngeal cancer are sneezing, snoring, difficulty breathing, nasal deformity, or bloody and other discharge from the nose or mouth. “Although canine canine canine can be diagnosed and treated fairly easily, vets in the UK may not be familiar with the signs of the disease because it is so rare here,” added Dr Strakova. Transmissible cancers are also found in Tasmanian devils and marine bivalves such as clams and mussels. The researchers say that studying this unusually long-lived cancer could also be useful in understanding how human cancers work. The findings were published in the journal Veterinary Record.
