Have Sexually Transmitted Diseases?
Do dogs have sexually transmitted diseases? Learn about canine STDs like Brucellosis, CTVT, and CHV — symptoms, transmission, treatment, and prevention.
The question "do dogs have sexually transmitted diseases" comes up more often than you might think, especially among owners of intact dogs, hobby breeders, and those who've adopted unaltered rescues. The direct answer is YES — dogs can and do contract several sexually transmitted diseases (STDs), though the landscape looks quite different from human STDs. Some are relatively common in intact populations, while others are rare but serious. Understanding these conditions matters whether you're planning a breeding, managing a multi-dog household with intact animals, or simply curious after noticing unusual symptoms.
What Sexually Transmitted Diseases Affect Dogs?
Three primary sexually transmitted infections are recognized in canine veterinary medicine, each with distinct transmission routes, symptoms, and prognoses:
| Disease | Pathogen | Primary Transmission | Prevalence in US |
|---|---|---|---|
| Canine Brucellosis | Brucella canis | Venereal, contact with aborted fetuses/fluids | Low (1-8% in kennels) |
| Canine Transmissible Venereal Tumor (CTVT) | Cancerous cell line (allograft) | Direct contact with tumor cells during mating | Rare in US; common in tropical/subtropical free-roaming populations |
| Canine Herpesvirus (CHV-1) | Canid alphaherpesvirus 1 | Venereal, nasal secretions, transplacental | Moderate (estimated 30-60% seroprevalence in adults) |
A fourth condition — Canine Papillomavirus — can occasionally spread during mating through mucosal contact, though it more commonly transmits through general close contact and shared environments. It causes oral or genital warts (papillomas) that typically resolve on their own in immunocompetent adults within 1-5 months.
Canine Brucellosis: The Most Significant Canine STD
Caused by the bacterium Brucella canis, this is the most clinically important sexually transmitted disease in dogs. According to the Merck Veterinary Manual, it primarily affects breeding kennels and causes devastating reproductive failures.
Symptoms to Watch For
- In males: Epididymitis (swollen, painful testicles), scrotal dermatitis, infertility, reluctance to breed
- In females: Late-term abortion (typically 45-55 days of gestation), stillbirths, weak puppies, vaginal discharge lasting 1-6 weeks post-abortion
- In both sexes: Lethargy, lymph node enlargement, spinal inflammation (diskospondylitis), recurrent fevers
Onset varies: abortion in females typically occurs 30-57 days after infection. Males may show testicular changes within 3-5 weeks. Some dogs remain asymptomatic carriers for months or years, silently shedding bacteria in semen, urine, and vaginal discharge.
Diagnosis and Treatment
Your veterinarian will run serological testing — specifically a Rapid Slide Agglutination Test (RSAT) as a screening tool, followed by tube agglutination or PCR confirmation. Testing costs typically range from $75-$200 depending on the lab and methodology.
Treatment involves a prolonged antibiotic course: doxycycline combined with streptomycin or enrofloxacin for a minimum of 3-4 weeks. However, B. canis is notoriously difficult to fully eradicate. Even after treatment, dogs may remain carriers. Many veterinary reproductive specialists recommend spaying/neutering infected dogs to eliminate the transmission risk entirely.
- Your pregnant dog aborts or delivers stillborn puppies
- An intact male shows swollen, painful, or discolored testicles
- Your intact dog has persistent vaginal or preputial discharge
- A recently bred dog develops recurrent fevers or spinal pain
Note: Brucella canis is zoonotic — it can infect humans, especially immunocompromised individuals. Handle aborted materials with gloves and wash hands thoroughly.
Canine Transmissible Venereal Tumor (CTVT)
CTVT — also called infectious sarcoma or Sticker tumor — is one of the most remarkable diseases in all of veterinary medicine. It's one of only three known naturally transmissible cancers in the animal kingdom. Rather than being caused by a virus or bacterium, CTVT involves the direct transfer of living cancer cells from one dog to another during mating or close contact.
What It Looks Like
Tumors appear as cauliflower-like, friable (easily bleeding) masses on the external genitalia — the vulva in females and the prepuce/penis in males. They typically develop 2-6 months after exposure. Tumors may also appear on the face, mouth, or skin if a dog licks or sniffs an infected area.
Prognosis and Treatment
The good news: CTVT has an excellent prognosis with treatment. According to AKC health resources and veterinary oncology literature, chemotherapy with vincristine achieves complete remission in approximately 90-95% of cases, typically within 3-6 weekly treatments. Cost ranges from $200-$500 for a full treatment course at general practice, higher at specialty oncology centers.
Without treatment, CTVT can metastasize (spread to lymph nodes, liver, lungs) in approximately 5-10% of cases, though spontaneous regression can occur in some dogs after 3-9 months. Treatment is strongly recommended rather than waiting.
Canine Herpesvirus (CHV-1): The Puppy Killer
While CHV-1 can transmit sexually between adult dogs, its most devastating impact falls on neonatal puppies. Adult dogs typically show mild or no symptoms — perhaps mild nasal discharge or small genital vesicles — but infected puppies under 3 weeks old face mortality rates approaching 80-100%.
The Fading Puppy Syndrome Connection
CHV-1 is a leading cause of "fading puppy syndrome." Puppies infected in utero or during the first weeks of life develop:
- Failure to nurse or weak suckling reflex
- Constant crying or paddling motions
- Nasal discharge and difficulty breathing
- Abdominal pain and hemorrhages
- Death within 24-48 hours of symptom onset
The virus thrives at lower body temperatures, which is why neonatal puppies (who cannot thermoregulate) are so vulnerable. Maintaining whelping box ambient temperature at 85-90°F (29-32°C) for the first week is critical.
Prevention: The CHV Vaccine
A vaccine (Eurican Herpes 205, available in some markets) can be given to breeding females — once before mating and again 1-2 weeks before expected whelping. This significantly reduces puppy mortality. Discuss availability and protocol with your veterinarian, as vaccine licensing varies by country.
How Do These Diseases Spread Beyond Mating?
While sexual contact is the primary route, these diseases have secondary transmission pathways that matter in multi-dog households:
| Disease | Non-Sexual Transmission Routes |
|---|---|
| B. canis | Contact with urine, aborted fetuses, placental fluids; contaminated surfaces (kennel runs, shared bedding) |
| CTVT | Licking, sniffing, or biting tumor sites on another dog |
| CHV-1 | Nasal secretions, aerosol droplets (short range), transplacental, contact during whelping |
This is why B. canis outbreaks can sweep through kennels even when dogs aren't actively breeding — shared water bowls, grooming tools, and kennel staff hands can all carry the bacteria.
Prevention: Protecting Your Dog From Canine STDs
The prevention hierarchy for canine sexually transmitted diseases follows a straightforward framework:
- Spay/neuter: The single most effective prevention. Removes the sexual transmission route entirely and eliminates most reproductive tissue susceptible to CTVT and CHV complications. Average cost: $200-$600 at private clinics, $50-$150 at low-cost clinics.
- Pre-breeding testing: If you're breeding, both dogs should be tested for B. canis before mating. RSAT screening costs $75-$200 and takes 2-5 days for results. Reputable breeders test annually and before each breeding.
- Avoid uncontrolled mating: Free-roaming intact dogs are at highest risk. Keep intact dogs secured and supervise outdoor time.
- Quarantine new additions: When introducing a new intact dog to a breeding household, isolate for 30 days and test before contact with your existing dogs.
- Vaccinate breeding females for CHV-1: Where the vaccine is available, follow the pre-breeding and pre-whelping protocol.
What About Other Infections Passed During Mating?
While not classified as classic STDs, several infections can transmit between dogs during breeding:
- Mycoplasma and Ureaplasma: These bacteria can inhabit the reproductive tract and may contribute to infertility, prostatitis, or endometritis. They're considered opportunistic rather than primary STDs.
- Canine influenza and Bordetella: Close face-to-face contact during mating can spread respiratory pathogens — though this is contact transmission, not truly venereal.
- External parasites: Fleas, ticks, and mites easily transfer between dogs during the close physical contact of mating.
Frequently Asked Questions
Can dogs get STDs from humans?
No. The pathogens that cause canine STDs are species-specific. Brucella canis, CTVT cells, and CHV-1 cannot infect humans through the same transmission routes. However, B. canis is zoonotic in the reverse direction — humans can contract it through contact with infected dog fluids (especially aborted materials), though human cases are rare and typically mild.
Can a spayed/neutered dog get a sexually transmitted disease?
Spayed and neutered dogs cannot contract diseases through sexual transmission since they are not mating. However, if a dog was infected before being altered, B. canis can persist as a chronic infection. CHV-1 can remain latent and reactivate under stress. CTVT would not occur without mating contact.
How common are STDs in pet dogs?
In the general US pet dog population — where approximately 80% of dogs are spayed or neutered according to AVMA demographics data — canine STDs are uncommon. Risk concentrates in intact dogs in breeding kennels, free-roaming dog populations, and regions with high stray dog density. The average spayed/neutered pet dog in a managed household faces negligible risk.
Should I test my adopted intact dog for STDs?
Yes, especially if the dog came from a stray background, a high-volume breeding operation, or a region with free-roaming dog populations. A Brucella canis RSAT screening ($75-$150) is a reasonable baseline test. If you plan to keep the dog intact, discuss a full reproductive health evaluation with your veterinarian.
Is canine brucellosis curable?
Treatment can clear active infection in many cases using 3-4 weeks of combination antibiotics, but complete eradication is not guaranteed. Some dogs remain chronic carriers despite treatment. This is why many veterinarians and the CDC recommend spaying/neutering infected dogs and removing them from breeding programs entirely.
What's the difference between CTVT and other cancers?
Unlike typical cancers that arise from a dog's own mutated cells, CTVT involves the physical transfer of living cancer cells from one dog to another. These tumor cells are genetically distinct from the host dog — they're essentially parasites. CTVT cell lines have been transmitted between dogs for an estimated 6,000-11,000 years, making them one of the oldest known living cell lines on Earth.
Aaron Whyte
All our authors care for dogs every day — read more of their work on the authors page.
