Highly Contagious Disease Still Threatens These Pets

Analysis by Dr. Karen Shaw Becker

distemper in dogs

Story at-a-glance -

  • Canine distemper virus (CDV) is a highly contagious, life-threatening disease that is no longer common in the U.S., but still poses a threat to certain populations of puppies and dogs
  • Signs of distemper often follow a pattern that begins with upper respiratory tract symptoms and progresses to gastrointestinal symptoms, and finally to neurologic symptoms
  • Since there is no medical cure for canine distemper, treatment focuses on managing symptoms and making the patient as comfortable as possible using both conventional and alternative therapies
  • CDV can be prevented with a single well-timed vaccine, followed by a titer test four weeks post-vaccination to ensure immunity

Because puppy shots include vaccination against distemper, fortunately, the virus — also known as Carre’s disease and once called “hard pad” disease — is relatively rare in dogs in the U.S. today.

We’re fortunate because not that long ago, the canine distemper virus (CDV) was a common killer of canine companions. Other animals, including cats, are also susceptible, but dogs are the primary host. The disease is caused by a type of Morbillivirus and is closely related to the measles virus in humans.

Despite the availability of distemper vaccines, we still occasionally see cases of infection, most commonly in shelter and foster puppies, dogs acquired from backyard breeders and dogs imported from outside the U.S. The rescued puppy population in shelters is at greatest risk for CDV due to a number of factors including stress, poor nutrition, immature or suppressed immune systems, the presence of gastrointestinal (GI) and/or external parasites, and other health issues.

How Canine Distemper Spreads

Non-immunized dogs who are exposed to an animal infected with CDV carry a high risk of contracting the disease, as do puppies born to an infected mother, and young dogs under extreme stress or who are immunocompromised. Dogs exposed to wildlife may also have a heightened risk of infection.

Bacterial infections, especially of the respiratory or GI tract, may also make dogs more susceptible to the virus. On rare occasions, improperly attenuated CDV vaccines have also been implicated as a cause.

Most dogs are exposed to the virus when they inhale the respiratory secretions of an infected animal, or come in direct contact with infected feces, urine or saliva. CDV can also be spread through direct or indirect contact with bedding, bowls or other items belonging to an infected dog.

In susceptible dogs (meaning dogs whose immune systems are unable to mount an effective defense), the virus first reproduces in the respiratory tract and then moves on to the lymph nodes and the lymph and blood circulatory systems throughout the body. CDV can also infect the skin, GI and urogenital tracts, central nervous system and other areas of the body.

Infected dogs can shed the virus for up to five days before symptoms appear, and for several months after exposure, even when no symptoms are present.

Symptoms of CDV

The period between exposure and the development of symptoms in unprotected dogs can be from about a week to as long as six weeks, however, most dogs become symptomatic within one to four weeks.

The virus often (but not always) follows a pattern in which symptoms first involve the upper respiratory tract, then the GI tract and finally the central nervous system. Initially, dogs show signs consistent with an upper respiratory infection, including a persistent cough, sneezing, discharge from the nose and eyes, a high fever (103.5 degrees F or higher), fatigue and lethargy.

At around the same time or just after the upper respiratory symptoms appear, as the infection moves to the GI tract, there can be vomiting, diarrhea, loss of appetite and weight loss.

Within one to three weeks, neurological signs may develop, including behavior changes, myoclonus (jerking muscles) and seizures — often a type called “gum chewing” in which the dog intermittently makes rhythmic chewing motions. Affected dogs are also susceptible to secondary bacterial infections.

The severity of symptoms varies depending on immune status. Dogs with competent immune systems are often able to successfully fight the infection, clear it from their bodies and suffer no long-term effects. Less fortunate dogs can end up with permanent tooth enamel, vision or neurologic damage.

In addition, certain strains of CDV can cause an abnormal enlargement or thickening of the pads of the feet, which is why the disease was sometimes called “hard pad” disease. In dogs with weak or compromised immune systems, death can result in two to five weeks after initial exposure, and sadly, this occurs about 50% to 75% of the time. Very young and elderly dogs have the highest rate of death from distemper.

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Diagnosing Distemper

Veterinarians typically run a complete blood count (CBC) and serum biochemistry profile on dogs suspected of having contracted distemper. These tests provide a lot of information about the infection, organ function and the dog’s overall health.

A urinalysis is also performed, since viral antigens can be found in urine sediment. Advanced blood tests can reveal positive antibodies for the virus; however, these tests can’t distinguish between antibodies resulting from vaccination and those resulting from exposure to CDV. X-rays are really only necessary if pneumonia is suspected.

The best way to definitively diagnose canine distemper in a living dog is a fluorescent antibody test that can be performed on blood, respiratory or tonsil samples, cerebral spinal fluid, bone marrow or urine.

If the disease is in the very early stages, samples from the conjunctiva (the corners of the eye) can also be tested for antibodies. A polymerase chain reaction (PCR) test is also now available that detects distemper virus in blood samples and is considered very reliable.

Ultimately, a distemper diagnosis can be confirmed by considering the dog’s history, the results of the veterinary exam and PCR testing with blood, urine or a conjunctival sample. On very rare occasions, there are cases of CDV that for whatever reason can’t be definitively diagnosed.

Treatment Options

No specific conventional therapy exists for canine distemper, so treatment focuses on managing symptoms and making the patient as comfortable as possible. The disease can be fatal, and the most important factor influencing a dog’s outcome is whether the virus has affected the central nervous system, and if so, to what extent.

Dogs diagnosed with CDV must be hospitalized and isolated from other animals. Conventional treatment includes antibiotics to address pneumonia if it’s present, cough medications, intravenous (IV) fluids, medications to reduce nausea and diarrhea, anti-seizure medications if necessary and pain management.

Integrative veterinarians will add intensive immune support during this time, including Kyosenex Prime (a purified thymus extract), IV vitamin C, hyperbaric oxygen therapy and ozone therapy as well. Many integrative/holistic veterinarians find homeopathic distemper nosodes very beneficial for reducing the duration of infection and minimizing the severity of symptoms and disease progression, especially if they’re used early on.

Since dogs can continue to shed the virus for weeks to months after recovery from distemper, they should be kept away from other dogs during this time. All surfaces, bedding and any object the sick dog has been in contact with should be cleaned and disinfected or thrown away. The virus is sensitive to ultraviolet light, heat and drying, and tends to linger in cold environments more so than in warm climates.

Preventing CDV

Veterinary vaccine authority Dr. Ronald Schultz believes one well-timed canine distemper vaccine for puppies is the best prevention against this highly contagious disease. Additional vaccinations against distemper are not necessary if a titer test completed two to four weeks after the vaccination shows the puppy was successfully immunized against the disease.

Dr. Richard Pitcairn, a homeopathic veterinarian and author of the bible of holistic health care for pets, “Dr. Pitcairn's Complete Guide to Natural Health for Dogs & Cats,” advocates the use of distemper nosodes prophylactically for puppies. In addition, creating a strong and vibrant immune system by making excellent nutritionally balanced, species-appropriate diet choices early on in a puppy’s life will help bolster your dog’s innate defenses against distemper and other infectious diseases.

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