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Transmissible venereal tumor

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Complications When to see a vet Prognosis FAQ Sources Affected species

What is it?

Transmissible venereal tumor, often abbreviated TVT, is a particular cancer: it does not arise from the cells of the affected dog, but is transmitted from one dog to another in the form of living tumor cells which implant themselves on the mucous membranes. It most often develops on the genitals, in the form of red, irregular masses that bleed easily. It is present in populations of free-ranging or poorly monitored dogs around the Mediterranean, including Tunisia, where mating takes place without control. It is also one of the rare canine cancers that generally responds very well to treatment.

Key point

The word “cancer” is scary, but it is one of the most curable in dogs. An affected street dog is not a hopeless case: if properly taken care of, it most often recovers and ceases to be contaminating.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

Vulvar discharge Swelling Difficulty urinating Nosebleed Swollen lymph nodes Scabs and skin lesions Licking the genital area Non-healing wound

In females: cauliflower-shaped mass at the vulva, pink or bloody discharge, insistent licking of the area.

In males: mass on the penis or sheath, drops of blood at the end of the sheath without urination, repeated licking.

Friable masses that bleed at the slightest contact, sometimes confused with prolonged heat or a urinary infection.

Discomfort in urinating when the mass is large.

Groin lymph nodes enlarged.

More rarely, localization in the nose or mouth, contracted by licking or sniffing an affected conspecific: nosebleeds, repeated sneezing, facial deformation.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

The cancer cells themselves constitute the agent of the disease: they pass from one dog to another and graft onto a weakened mucous membrane.

It is neither a virus, nor a bacteria, nor a parasite: it is a tumor tissue which is transplanted naturally.

A weakened immune system favors the implantation and growth of the tumor.

Whole dog, not sterilized, with access to conspecifics for reproduction.

Lives in freedom or semi-freedom, frequent contact with unmonitored dogs.

Groups of dogs: overcrowded neighborhoods, farms, shelters.

Young adult to adult: this is the reproductive age, therefore that of risky contacts.

Decrease in immune defenses, whatever the cause.

Transmission

Transmission occurs by direct contact between mucous membranes, mainly during mating: the tumor cells pass from the carrier dog to the partner.

It can also occur during licking, sniffing or biting between dogs, which explains the shapes of the nose and mouth.

The disease therefore circulates where dogs reproduce freely, without this being due to a lack of care on the part of anyone: street dogs, neighborhood dogs fed by the neighborhood, farm dogs left free.

It is not transmissible to humans or to other domestic species in the household.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

The veterinarian examines the genitals, nasal cavity and mouth, and palpates the lymph nodes in the groin.

The appearance of the masses is very suggestive, but the diagnosis is confirmed by a puncture or smear: the cells of this tumor have a characteristic appearance under the microscope, which makes the diagnosis quick and inexpensive.

A biopsy is reserved for doubtful cases.

A general examination and blood test are carried out before starting treatment.

It is important not to confuse these masses with a genital infection or prolonged heat: persistent bloody discharge in a dog or female dog always merits examination.

Treatment

This tumor is one of those that respond best to treatment: chemotherapy, administered by the veterinarian in spaced sessions, generally melts the masses, including when they are large.

The treatment continues until complete disappearance, then a check is carried out to ensure that nothing remains.

Surgery alone is less reliable, because residual cells can leave; it maintains an interest in certain unique or complementary masses.

Radiotherapy is effective but rarely accessible.

Local cleaning and treatment of associated infections improve comfort during treatment.

Sterilization, discussed with the veterinarian, limits reproductive behavior and therefore recontamination.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

Avoiding uncontrolled mating is the most effective measure: controlling the exits of the female dog in heat and the entire male.

Sterilization greatly reduces sexual contact and therefore the risk.

Have any newly adopted dog examined, especially if it comes from the street or from a shelter: screening is simple and treatment works well.

Treating affected dogs is also a preventive measure for others: a treated dog ceases to be a source of contamination.

Sterilization campaigns for free dog populations remain the most effective collective lever.

Possible complications

Repeated bleeding from friable masses, which can lead to anemia.

Infection of ulcerated masses, with odor and pain.

Urinary obstruction when a large mass interferes with the flow of urine.

In nasal forms, facial deformation and nosebleeds are difficult to control.

Diffusion to other organs, possible but uncommon, especially in weakened dogs.

When to see a veterinarian

You see a red, irregular mass on your dog's genitals.

Drops of blood appear at the level of the sheath or vulva outside of heat.

Your dog seems to be in heat that never ends, with persistent bloody discharge.

Your dog is constantly licking his genitals.

He has difficulty urinating or can no longer do so: consult urgently.

He has repeated nosebleeds or sneezes with blood.

Prognosis

The prognosis is good in the vast majority of cases: treated correctly, the tumor most often regresses completely and the dog recovers.

More difficult situations concern very weakened dogs, old and extensive forms, or nasal locations.

Treatment interrupted too early risks a resumption of the disease: it is important to complete the planned sessions, even when the masses have already disappeared.

Frequently asked questions

Can my dog transmit this tumor to me?

No. It is only transmitted from dog to dog, by direct contact between mucous membranes, especially during mating. Neither you, nor the children, nor the house cat are affected.

Should I isolate my dog from other dogs?

Above all, avoid any mating and limit close contact, muzzle against genitals, as long as the masses are present. Walking on a leash and normal family life are no problem.

I adopted a street dog, should I have it checked?

It’s a good idea, as with the entire adoption review. The examination only takes a few minutes and the diagnosis, if necessary, is made quickly. This disease is well treatable: discovering it is not bad news, it is the beginning of the solution.

The masses disappeared after a few sessions, can we stop?

No, and this is an essential point. Cells invisible to the eye can remain and cause the tumor to start again. The veterinarian decides to stop based on specific criteria, generally after continuing the treatment beyond the apparent disappearance of the masses.