What do dogs do when they greet each other? Sniff each other, of course! But did you know that this normal greeting by your pet is also causing them cancer?
As a dog owner, you might be very familiar with your dog sniffing the rear end of other animals. After all, this is how they gather information about each other. It’s an integral ritual that dogs do when they meet each other.
However, you might be confused as to how this happens. After all, cancer is not a contagious disease. But what if it was?
But don’t be alarmed, this cancer is not caused by the transmission of a virus. These are cancer cells being physically passed from the infected dog to healthy dogs.
Dogs often sniff each other to find out things about each other and obtain information that they need to get along and survive.
In a new study conducted by researchers from the Transmissible Cancer Group from the University of Cambridge, they found that male dogs are four or five times more likely to be infected with the nasal and oral form of canine transmissible venereal tumour (CVCT) than their female counterparts. The CVCT cancer cells are transmitted to healthy dogs if they sniff the genitals of infected dogs.
Canine transmissible venereal tumour.
Canine transmissible venereal tumour causes unsightly tumours to form around the affected dog’s genital regions. However, it can also affect other areas of the dog, including the nose, mouth, and skin. CVCT is most commonly transmitted during mating.
Transmission of canine transmissible venereal tumour. Credit: Andrea Strakova.
While CVCT is fairly common and affects thousands of dogs all over the world, nasal and oral versions of the disease are rare. These are transmitted when a healthy dog sniffs the genital area of a dog that is infected with CTVT.
The researchers studied almost 2000 dogs with CTVT. Out of the 2000 cases, only 32 of them were oral or nasal variations. Additionally, 27 of the 32 cases were male.
Male dogs are more susceptible.
The difference in male and female behaviour might contribute to this risk. Male dogs have a tendency to sniff or lick the genital regions of their female counterparts. Female dogs are less likely to engage in this behaviour.
Genital tumours are also more exposed on a female dog, making it more accessible for sniffing and licking. Tumours on male dogs, on the other hand, are often hidden within the sheath.
Canine transmissible venereal tumour symptoms.
For the nasal and oral versions of CVCT, the most common symptoms are:
- Sneezing
- Snoring
- Nasal Deformation
- Having Difficulty Breathing
- Nose or mouth discharges.
Older than most cancers
The earliest documented cases of cancer in humans were found in Egypt at around 1500 BC. CVCT however, came from the cells of a dog that lived up to 8000 years ago. Using genetics, researchers determined that the dog in question was probably a husky-like animal that lived in central or northern Asia.
CVCT spread from the ancient husky-like animal, jumping from dog to dog ever since. Every single form of CVCT in dogs today is derived from the same husky-like dog.
The study was led by Professor Elizabeth Murchison (pictured). Credit: Transmissible Cancer Group.
CVCT in Australia.
CVCT affects dogs all over the world. However, CVCT cases are mostly found in countries with a large population of free-roaming dogs.
Although rare in Australia, cases have slowly risen over the past couple of years. However, CTVT is not expected to be a common case in Australia as there are few free-roaming dogs.
Transmissible cancers are also found in one of our own native animals: the Tasmanian devil. Transmissible cancers can also be found in molluscs such as clams and muscles. Scientists aren’t sure if there are any transmissible cancers that exist in humans.
Given the ancestry of CTVT, scientists are hoping that it could help our understanding about how human cancers work too.
While CVCT is not expected to be common in Australia, there is another disease spreading around Australia that could harm your dog. Find out more about the ‘new pandemic’ here.
