A rare and highly contagious form of dog cancer has been confirmed to be spreading within the UK for the first time in more than half a century, prompting urgent warnings from veterinary experts. A significant number of cases have been linked to dogs imported from Eastern Europe.
Researchers at the University of Cambridge have urged British vets and dog owners to remain vigilant following the resurgence of canine transmissible venereal tumour (CTVT). While a small number of isolated cases have emerged in Britain over the years, experts have now confirmed that active dog-to-dog transmission is taking place across the UK.
How CTVT spreads
Unlike conventional cancers that develop within a single animal's body, CTVT is one of only a handful of known contagious cancers in the world. It spreads directly between dogs through the transfer of living cancer cells.
Most commonly, it is passed between dogs during mating. However, it can also spread through close physical contact such as sniffing, licking, or biting infected areas.
Why did it disappear, and why is it back?
CTVT was once widespread in Britain during the 19th and early 20th centuries, but was effectively eradicated in the UK more than 50 years ago. Stringent dog control legislation, the elimination of free-roaming stray populations, and widespread neutering programmes successfully halted the disease from circulating.
Today, its reappearance is thought to be strongly connected to the rising number of rescue dogs being brought into the UK from overseas. CTVT remains common in areas of Eastern Europe and other regions with significant stray dog populations.
As current UK border and import inspections do not test for this particular cancer, infected dogs can arrive in the country without detection and transmit the disease to local pets.
Signs to look out for
Since CTVT has been absent from Britain for decades, most practising UK vets have never encountered a case first-hand. To avoid misdiagnosis and monitor the spread of the disease, the University of Cambridge Transmissible Cancer Group has established a national pilot study. Through this initiative, vets throughout the country can submit tissue samples to Cambridge for complimentary specialist PCR testing to rapidly confirm suspected cases.
Dog owners are urged to watch their pets carefully, particularly if their dog was rehomed from abroad or frequently interacts with imported rescue dogs. The main symptoms of CTVT include:
- Red, fleshy, or cauliflower-like lumps around the genital area that bleed or crumble easily.
- Bloody discharge from the genitals.
- Unusual growths or swelling around the nose, mouth, or face, which can occur if the cancer spreads via sniffing or licking.
- Problems peeing, as CTVT can make it difficult for dogs to urinate.
- Excessive licking of the genital area.
- Swelling around the genitals.
Can it be treated?
Veterinary specialists emphasise that CTVT is highly treatable. Unlike numerous other forms of cancer, it seldom spreads to internal organs and responds remarkably well to a standard chemotherapy drug called vincristine. The vast majority of healthy dogs make a full recovery.
Vet Dr Joanna Woodnutt from pet insurer ManyPets advises owners against panicking, as the condition is uncommon, treatable and the symptoms are typically straightforward to identify. She said: "We know it's worrying to hear the word cancer, but CTVT has a good prognosis if it's caught early. The key thing is to know what to look for and to get your dog to a vet as soon as possible if you notice anything unusual."
Dr Woodnutt added: "Vets usually treat CTVT with chemotherapy, and most dogs respond well. The Transmissible Cancer Group at the University of Cambridge is offering free testing to vets across the UK, so if you're worried, speak to your vet."
She also cautioned that certain signs are less apparent and might be mistaken for other ailments. "Bad breath, dental problems, frequent sneezing, nosebleeds, facial swelling and sores or ulcers on the skin can all be linked to CTVT," she said. "These symptoms are common in lots of conditions, so your vet will be able to work out whether CTVT is the cause or something else is going on."
How to protect your dog
A statement on the University of Cambridge website reads: "The Transmissible Cancer Group is now offering their PCR-based diagnostic test for CTVT free of charge to vets across the UK. If you suspect a CTVT case, please, get in touch. We accept samples in various formats and will return a CTVT diagnostic result within a clinically useful timeframe."
Dr Woodnutt outlined four straightforward steps owners can follow to reduce the risk:
- Keep them on a lead: restrict unsupervised time outdoors and keep dogs on a lead while out and about.
- Consider neutering or spaying: this can diminish a dog's urge to mate, which is the primary way CTVT spreads.
- Get pre-breeding checks: ask your vet for a genital exam before breeding your dog.
- Keep up with routine check-ups: these give your vet the best chance of spotting problems early.
She said: "If you've recently adopted a dog from abroad, it's worth mentioning this to your vet at their next check-up. Catching it early makes all the difference."
