Venereal tumours: another important reason to sterilise your dog

Sexually transmitted diseases are not something one naturally associates with animals but venereal tumours do unfortunately occur all too often in South Africa.

Transmissible venereal tumour, or TVT, is a naturally occurring tumour that is sexually transmitted from one dog to another. It is also transmitted via licking or sniffing of an affected area. It is not transmissible to humans.

A high number of cases tend to be seen where there are large dog populations, particularly in areas where there are many unsterilised animals. TVT is most commonly seen in young, unneutered dogs.

Symptoms of venereal tumours

A red, tumorous mass bulging out of the surface membrane of the vagina, or on the penis.

There may be blood dripping from the vagina or penile foreskin. The dog will usually lick the affected area repeatedly.

Causes of venereal tumours

This condition is the result of direct contact with tumour cells from a diseased animal. It is transmitted through the act of sex, and can also be transmitted by oral contact. Unsterilised, free roaming dogs are at greater risk of acquiring and spreading this disease.


Should you notice any of the symptoms mentioned above, see your vet immediately. He/she will need your dog’s complete health history and as much information as possible about when you first noticed symptoms, how much your dog roams, whether you’ve been breeding your dog etc.

Your dog will undergo a physical examination and tissue and fluid samples will be taken for testing.

Prognosis and treatment

This type of tumour rarely spreads to other parts of the body but your vet will need to confirm that it is not a malignant form of cancer. Your vet may require chest and abdominal x-rays to ensure there is no spread. Treatment will be based on the results of these x-rays and fluid and tissue samples.

In some dogs, the tumour may disappear spontaneously without any treatment. Or your veterinarian may need to surgically remove it and prescribe chemotherapy drugs. They do not cause hair loss or nausea as with humans but they are very expensive.

If the tumour is benign (i.e., not cancerous) a complete cure is generally expected. If it is malignant, your dog’s overall wellbeing will be the deciding factor in how well treatment goes.

It is important to discuss every aspect of your dog’s treatment with your vet and to follow the plan exactly as laid out.

As with most serious diseases, prevention is always preferable to cure – for your dog and your wallet! Sterilise your pet as soon as he or she  is old enough and prevent the spread of venereal tumours.