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Distemper

Canine distemper virus (CDV) is highly contagious and infective immediately upon passing in a dog’s stool, urine, or respiratory secretions (coughing, sneezing, eye/nose drainage). Distemper is essentially everywhere and can cause awful symptoms in unvaccinated or not fully vaccinated (up to date) dogs. Distemper causes a two-phased infection. The first phase includes respiratory signs that look like “kennel cough” and digestive upset with signs like vomiting, soft stool, or bloody diarrhea. The second phase can transition to skin infection with hardening of nose and paws, and neurologic symptoms like paralysis and seizures. Both phases can be life-threatening. Detection of distemper in stool or respiratory secretions likely indicates infection and shedding of virions. Prevention is boiled down to one word: vaccinate. Canine distemperis a necessary (core) vaccine for every puppy and dog, regardless of breed or lifestyle.

Canine distemper virus (CDV) is a highly contagious viral disease of dogs. Distemper is often fatal, and dogs that survive usually have permanent, irreparable nervous system damage.

American Veterinary Medical Association

All About Distemper

What Is Distemper?

Canine distemper virus (CDV) is a very serious, even fatal viral pathogen of puppies, dogs, and other animals like ferrets, skunks, raccoons, wild dogs and wild cats.[1,2] CDV is Canine morbillivirus, belonging to the family Paramyxoviridae. This viral family includes human measles (Measles morbillivirus), human mumps (Mumps orthorubulavirus) and rinderpest (Rinderpest virus). Rinderpest was a devastating disease of cattle and domestic buffalo that was eventually eradicated (2001) after decades of vaccination.

Distemper is essentially everywhere and can cause awful symptoms in unvaccinated or not fully vaccinated (up to date) dogs. Young puppies (3 to 6 months of age) are especially vulnerable.[7] Fortunately, modern distemper vaccines are extraordinarily safe and effective, making this an easily preventable disease in most puppies and dogs.[5,6,7] If there is just one learning about CDV, it’s to vaccinate dogs for distemper early and booster the vaccine throughout their lifetimes.[5]

Many dogs that become infected are able to stay healthy.[7] If they do get sick, symptoms can progress quickly and be severe. Signs of distemper start with fever, lethargy (drowsiness), and maybe loss of appetite usually within a few days to a week after infection. Respiratory signs that look like “kennel cough” may follow. Digestive upset is also commonly part of the disease with signs like vomiting, soft stool, or bloody diarrhea.[1,3,4,6,7] A hardening or thickening of the nose and paws (“hard pad disease) can develop with or without skin infection.[4] In the nervous system, distemper can cause muscle twitches, head tilt, seizures, partial or complete paralysis, and death.[2,4,6]

Since the development and advancement of distemper vaccines, this virus is much less of a threat to the modern dog.[5] Thanks to widespread vaccination, clinical disease from distemper has been dramatically reduced compared to decades ago. Keep in mind that vaccination doesn’t prevent the dog from getting exposed to the virus in the environment, doesn’t prevent the dog from getting infected with distemper virus, nor prevent the dog from shedding the virus (in their stool, urine, or from their nose or mouth). Instead, vaccination prepares the dog’s immune system (antibodies) to aggressively defend the body if/when the real virus attacks. A properly vaccinated dog is very likely to fend off the viral attack and get only mild symptoms or not get sick at all. Simply put, the vaccine prevents dogs and puppies from getting severely ill or dying from Canine distemper virus.

How Common Is Distemper?

Canine distemper virus (CDV) is a highly contagious cause of respiratory and digestive distress, and even skin and nervous system disease. It causes infections in domestic dogs and wild carnivores including coyotes and wolves, as well as other animals like foxes, raccoons, skunks, bears, lions, and seals.[6,8] CDV can be found all over the world and is able to infect all breeds and ages of dogs, but is especially dangerous in young animals.[4,7]

Most dogs that get exposed to Canine distemper virus stay healthy and don’t show any symptoms.[6,8] If they do get sick, clinical signs are usually most severe in young, rapidly growing puppies that haven’t started or finished their distemper vaccination series. Infected dogs and puppies are at higher risk if also infected with other pathogens such as parvovirus, Salmonella spp., or Bordetella bronchiseptica.[7]

Assume that distemper is wherever dogs are housed or play together (kennels, day cares, dog parks, shelters). While it doesn’t survive long in the environment and is easily deactivated using common detergents and disinfectants, it is highly contagious between dogs.[6,8] Healthy-appearing dogs can shed distemper is their respiratory secretions (coughing, sneezing, barking, eye/nose drainage), urine, and stool.

Since the development and advancement of distemper vaccines, this virus is much less of a threat to the modern dog.[5] Thanks to widespread vaccination, clinical disease from distemper has been dramatically reduced compared to decades ago.

What Does Distemper Look Like?

Viruses are a lot smaller than bacteria and not visible with the magnification of a regular, optical microscope at a veterinary office or laboratory. This means that special types of testing are required to detect their presence in samples.

Canine distemper virus is a Morbillivirus, belonging to the family Paramyxoviridae. It is a large-sized virus (ranging from 150-250nm), especially in comparison to the much smaller Canine parvovirus (~25nm).[7] Distemper is a single-stranded RNA virus covered by a lipoprotein envelope. This lipid (fat) and protein wrapping helps protects the viral RNA for short transit times between animal hosts. This layer also contains surface “hooks” which the virus uses to attach and enter the animal cell. Cleaning products can be used on surfaces (countertops, kennels, cages) to damage the viral envelope which prevents the surface hooks from attaching to the animal cell. Enveloped viruses like distemper (and coronavirus) are fragile in the environment and are easily inactivated by common detergents and disinfectants.[6,7] It is also destroyed by heat, drying, and sunlight.

Viruses are not visible on a fecal O&P (ova (egg) and parasite) stool test (included in ClueJay Dog Stool Tests Level 1, 2, and 3). The O&P looks for worms and some types of coccidia, not bacteria and not viruses. Most of the time, a special Polymerase Chain Reaction (PCR) test is used to detect the presence of this parasite in respiratory secretions (eyes, nose, throat) or in dog stool (ClueJay Dog Stool Test Level 3).

What Symptoms Are Caused By Distemper?

The origins of the word “distemper” is to disturb, and it certainly can do that by affecting many body systems. Between 25-75% of dogs exposed may become infected and stay healthy.[7] If they do get sick, symptoms can progress quickly and be severe.

Signs of distemper start with fever, lethargy (drowsiness), and maybe loss of appetite usually within a few days to a week after infection. Respiratory signs that look like “kennel cough” may follow, including drainage from the eyes and nose (from clear to yellow or white), sneezing, and dry to moist coughing. Digestive upset is also commonly part of the disease with signs like vomiting, soft stool, or bloody diarrhea.[1,3,4,6,7] These symptoms represent the acute or early phase of infection as the virus multiplies and damages the tissues of the respiratory and digestive tracts. Dogs can die from this first phase of infection.

If the puppy or dog survives but is unable to clear the infection, other symptoms can develop from the virus spreading into the skin and nervous system within 1-3 weeks of exposure. A hardening or thickening of the nose and paws (“hard pad disease”) can develop with or without skin infection.[4] In the nervous system, distemper can cause muscle twitches, head tilt, seizures, partial or complete paralysis, and death.[2,4,6] Neurologic symptoms can be permanent if the dog survives this second phase of infection.

The pet’s age, stress level, breed, co-infections, and immune strength can all influence the response to infection.[7] Young puppies (3 to 6 months of age) are especially vulnerable.[7] Exposure to distemper during times of stress (from weaning, overcrowding, or poor nutrition) or other pathogen (parvovirus, Salmonella spp., Bordetella bronchiseptica) infections may increase the severity of illness.[7] Some different strains of Canine distemper virus have been identified which may affect the severity and duration of clinical disease.[7]

Distemper is dangerous to dogs and puppies because it attacks the lymph nodes of the body (immune defense) followed by infection and injury of the respiratory, digestive, and urinary systems, then onto the skin and nervous system. Damage to the lining of the stomach and small intestine (hampering the gut barrier) and lining of the lungs can let bacteria in (pneumonia). The overwhelmed immune system must then defend against both the multi-organ viral attack and bacterial invasion.[7]

Sometimes dogs exposed to distemper stay healthy because the exposure dose (number of viral particles) was low or their immune system was able to suppress it.[7] More likely it is because the dog or puppy was previously and properly vaccinated against distemper.

Many veterinarians have treated dogs with distemper and seen firsthand how awful this disease can be, which is why they so strongly recommend distemper vaccinations to puppies and dogs throughout their lives.[5]

How Do Dogs Get Distemper?

Canine distemper virus is spread when dogs live or play together in an indoor (household, kennel, shelter) or outdoor environment (day care, dog park). It is highly contagious by physical contact (eye and nose secretions), airborne (sneezing, coughing, barking), or through ingestion of urine or stool containing the viral particles (virions).[4] Since distemper doesn’t last long in the environment, the primary route of infection is from direct exposure to respiratory secretions.

Unlike many other parasites (e.g., most worms, coccidia, Salmonella), swallowing distemper isn’t necessary to get sick. The infection starts in the lymph nodes of the mouth and throat, spreads into the respiratory and digestive tracts, then throughout the body. Distemper gets into the dog’s mouth from licking the floor or toys, bedding, dishes, or simply breathing in airborne droplets carrying the viral particles.[4] Humans can contribute to spreading distemper virus on their shoes, equipment, or on their hands after handling infected dogs.

Infected dogs can shed distemper particles (virions) in their stool, urine, and respiratory secretions (coughing, sneezing, barking, eye/nose drainage), infecting other dogs and contaminating the environment for short periods of time with virions. Shedding starts by 7 days after exposure, lasts during the illness, and can persist another 60-90 days after recovery (shorter periods of shedding are more typical).[7] Properly vaccinated puppies and dogs exposed to distemper should be able to suppress the infection and not get sick. However, they can still be shedding the virions while appearing perfectly healthy. These virions shed from vaccinated dogs can still infect other dogs.

Assume that distemper virus could be wherever dogs are housed or play together (kennels, day cares, dog parks, shelters) since dogs can be shedding the virus even without signs of illness.[7] Puppies are more likely to get sick than older dogs.[2] Dogs that are immune-suppressed, fighting off other infections (intestinal pathogens), and/or in stressful conditions (like being transported/relocated or housed in groups) are more likely to get sick with distemper.[7]

Occasionally, the virus can also be spread from mother to puppy through the placenta in the womb, making vaccination of breeding dogs important.[4,7]

What Is The Distemper Life Cycle?

Outside of the animal (host) cells, Canine distemper virus takes the form of a particle called a virion. This is simply a single strand of RNA surrounded by a lipid (fat) and protein coat called an envelope. This membrane helps protects the viral RNA for short transit times between animal hosts.

Canine distemper virus is spread when dogs live or play together in an indoor (household, kennel, shelter) or outdoor environment (day care, dog park). It is highly contagious by physical contact (eye and nose secretions), airborne (sneezing, coughing, barking), or through ingestion of urine or stool containing the viral particles (virions).[4] Since distemper doesn’t last long in the environment, the primary route of infection is from direct exposure to respiratory secretions.

Dogs with distemper can shed viral particles (virions) in their stool, urine, and respiratory secretions, infecting other dogs and contaminating the environment for short periods of time with virions. Shedding starts within 7 days after exposure, lasts during the illness, and can persist another 60-90 days after recovery (shorter periods of shedding are more typical).[7]

The virion is the inert state (without metabolism or replication) of the virus, and only activates upon contact with an animal cell. Once distemper enters the new host animal, the virion envelope “hooks” to a dog cell and injects the viral RNA into that cell. The animal (host) cell is then essentially hijacked and forced to produce thousands of identical copies of the original virus, which get released as virions to infect thousands of other cells in that animal. This process destroys the host cells, leading to the classic clinical symptoms of distemper in the respiratory, digestive, skin, and nervous systems.

Many dogs that become infected stay healthy.[7] If they do get sick, symptoms can progress quickly and be severe. Signs of distemper start with fever, lethargy (drowsiness), and maybe loss of appetite usually within a few days to a week after infection. Respiratory signs that look like “kennel cough” may follow. Digestive upset is also commonly part of the disease with signs like vomiting, soft stool, or bloody diarrhea.[1,3,4,6,7] A hardening or thickening of the nose and paws (“hard pad disease) can develop with or without skin infection.[4] In the nervous system, distemper can cause muscle twitches, head tilt, seizures, partial or complete paralysis, and death.[2,4,6]

Can People Or Other Pets Get Distemper?

While closely related to human measles (Measles morbillivirus) and human mumps (Mumps orthorubulavirus), Canine distemper virus (CDV) has been documented in some primates (macaques) but is not considered a risk to people. Widespread measles vaccination campaigns in people may help keep CDV from adapting to become a human pathogen.[8]

Canine distemper virus might be better called “Carnivore Distemper Virus” due to its commonness infecting carnivores around the world. The list of animals at risk from this virus is long, including the fox, wolf, coyote, ferret, mink, skunk, wolverine, marten, badger, otter, raccoon, elephant, bear, seals, sea lions, some primates, large cats like lions, and others.[6,8] Canine distemper is highly contagious between dogs and susceptible wildlife. Domestic dogs (including feral populations) around the world are often responsible for transmitting distemper to wildlife or zoo animals.[6]

Domestic cats are not at risk from Canine distemper. Only a few reports have shown infection in cats but disease from infection has not been shown.[8] Pet ferrets on the other hand are at high risk from Canine distemper and should be vaccinated for protection against this virus.[2]

How Is Distemper Prevented & Treated?

Canine distemper is a serious disease with no cure. It can cause major problems for unvaccinated or improperly vaccinated dogs. Prevention is boiled down to one word: vaccinate. Canine distemper virus is a necessary (core) vaccine for every puppy and dog, regardless of breed or lifestyle.[5] Due to the close relationship between Canine distemper virus and human measles virus, some veterinarians will vaccinate very young puppies with a canine measles vaccine in order to give puppies even earlier immune protection from distemper.

Assume that distemper is wherever dogs are housed or play together (kennels, day cares, dog parks, shelters). Even healthy-appearing dogs can shed distemper is their stool and respiratory secretions (coughing, sneezing, eye/nose drainage).[6,7] Only take your puppy or dog to a daycare, grooming, boarding facility or training class where all dogs are required to be current on their immunizations.

Enveloped viruses like distemper (and coronavirus) are very fragile in the environment. It doesn’t survive in the environment for more than a few hours at room temperature. This makes these viruses much easier to inactivate using common detergents and disinfectants or by subjecting them to high temperature (sunlight) and drying.[7] It can survive up to a few weeks in shady environments at temperatures slightly above freezing.[6]

Preventing distemper is first about properly vaccinating but also requires a focus on hygiene. Distemper particles (virions) are highly contagious and infective immediately upon passing, so quickly remove stool and thoroughly clean indoor areas where dog stool, urine, and airborne respiratory particles have been present.[6,7]Avoid overcrowding or direct exposure to dogs at high risk of shedding the virus. Also don’t be a “fomite”. In other words, human handlers can spread distemper with grooming equipment, cleaning tools, or just on shoes and hands between dogs if not careful.

Treatment decisions for sick dogs are based on the severity of symptoms. Antibiotic therapy is for bacteria and has no effect on viruses. Antibiotics are not recommended for dogs who have no symptoms or mild signs that respond to supportive therapy like hydration, rest, and digestive support. Outpatient treatment for mild cases might include antiemetics (e.g., maropitant) to stop the vomiting, hydration, and careful nutritional support. Dogs with symptoms from distemper may need hospitalization and even intensive care, including intravenous (IV) fluids, electrolytes, nutrition, antibiotics (if sepsis suspected), antiemetics, etc.[1,4,7] Once neurologic symptoms set in (muscle twitches, head tilt, seizures, partial or complete paralysis), supportive treatment is much less successful.[7]

Where Are Distemper Medications Purchased?

ClueJay does not dispense or prescribe medications, and there are no FDA-approved antiviral medications in the U.S. for Canine distemper virus treatment. A positive finding of distemper does not always signal a need for treatment. Properly vaccinated dogs should be able to suppress the infection and remain healthy or get only mild symptoms. An unvaccinated or incompletely vaccinated dog or puppy is at much higher risk.

Important: Dogs or puppies with symptoms suspicious of distemper infection should consult with a veterinarian right away! Distemper infections can mimic many other illnesses like “kennel cough” (eye/nose drainage, coughing, sneezing) or intestinal parasite infections (soft stools, bloody diarrhea) during the first phase of infection. Early treatment can sometimes be the difference between life and death, especially in young dogs (3 to 6 months of age) that are unvaccinated or incompletely vaccinated.

Therapy decisions for sick dogs are based on the severity of symptoms. Antibiotic therapy is for bacteria and has no effect on viruses. Antibiotics are not recommended for dogs who have no symptoms or mild signs that respond to supportive therapy like hydration, rest, and digestive support. Outpatient treatment for mild cases might include antiemetics (e.g., maropitant) to stop the vomiting, hydration, and careful nutritional support. Dogs with symptoms from distemper may need hospitalization and even intensive care, including intravenous (IV) fluids, electrolytes, nutrition, antibiotics (if sepsis suspected), antiemetics, etc.[1,4,7] Once neurologic symptoms set in (muscle twitches, head tilt, seizures, partial or complete paralysis), supportive treatment is much less successful.[7]

While it is always best to consult with a veterinarian prior to administering any medication, even an OTC version, it is especially true for distemper given the potential for complicated symptoms and life-threatening illness. Always read the medication administration directions carefully and be on the lookout for potential side effects (like vomiting) when any medication is administered.

When/How Is Dog Stool Tested For Distemper?

Simply put, include a PCR test for Canine distemper virus whenever a dog has frequent or ongoing abnormal stools (soft stool or diarrhea) or other digestive problems. It should also be considered whenever a dog has respiratory symptoms consistent with “kennel cough” (eye/nose drainage, coughing, sneezing). Dogs shedding distemper virus are typically shedding virions in stool, urine, and respiratory secretions. Need details? Read on.

Most of the time, distemper infections are not discovered unless veterinarians are searching for the cause of diarrhea or respiratory problems in dogs or puppies. ClueJay Dog Stool Test Level 3 includes a Canine distemper virus by Polymerase Chain Reaction (PCR) assay along with PCR tests for other disease-causing protozoa, bacteria, and viruses found in dog intestines. These tests are designed to find the DNA (or RNA) of hard to find microbe pathogens. Screen for distemper in dogs with signs of digestive upset, most commonly loose stool or diarrhea (which may be bloody) with or without vomiting, respiratory signs like eye/nose drainage and coughing, loss of appetite, decreased energy level, and fever.[6,7] Once found, vets may encourage pet owners to test other dogs in the same household to determine if they are also shedding distemper.

Veterinarians recommend stool (fecal) testing puppies 2 to 4 times during their first year of life, and 1 to 2 times each year in adult dogs (every 6 to 12 months). Veterinarians often call this stool health test a “Fecal O&P”, with the O&P meaning “ova (eggs) and parasites”. It includes special preparations of the stool sample and analysis using a microscope to look for roundworms, hookworms, tapeworms, whipworms, and some types of coccidia. Viruses and bacteria are not visible on an O&P stool test (included in ClueJay Dog Stool Tests Level 1, 2, and 3). Most of the time, a microbe by PCR test is needed to detect the presence of this viral parasite in dog stool (ClueJay Dog Stool Test Level 3) or in dog respiratory secretions (eye/nose drainage and throat samples).

My Dog Tested Positive for Distemper

ClueJay Dog Stool Test Level 3 includes PCR assay tests for disease-causing bacteria, viruses, and protozoa found in dog intestines. One of those viruses is Canine distemper virus. A positive test means distemper viral RNA was detected in the stool. Most veterinarians then assume the dog is infected with distemper and shedding the viral particles (virions) in the stool. This viral shedding can represent an infection risk for other dogs and cats.

Important: Dogs or puppies with symptoms suspicious of distemper infection should consult with a veterinarian right away! Distemper infections can mimic many other illnesses like “kennel cough” (eye/nose drainage, coughing, sneezing) or intestinal parasite infections (soft stools, bloody diarrhea) during the first phase of infection. Early treatment can sometimes be the difference between life and death, especially in young dogs (3 to 6 months of age) that are unvaccinated or incompletely vaccinated.

A positive finding is not always associated with symptoms of illness and may not require treatment. Most properly vaccinated dogs infected with distemper will quickly suppress the parasite and never get sick or only have mild symptoms, but can still shed the virus.[7,8] It’s important to confirm with your veterinarian that your dog or puppy is current (up-to-date) with distemper vaccinations.

The PCR test can detect modified-live distemper vaccine virus in the stool for up to 3-4 weeks (usually only 1-2 weeks) after administration of the vaccine.[7] The dog is truly shedding distemper but it’s the vaccine virus, which is a good thing and not a health risk to other dogs.

A test result is not the same as a veterinarian’s diagnosis, so it’s always best to consult with a veterinarian about your dog’s test results to determine the safest and most effective treatment and prevention plan, and when to do follow-up stool tests. Some veterinarians may recommend rechecking a dog’s stool sample within 2-3 months after detection of distemper to confirm that the shedding has stopped. Distemper shedding can be a risk to other dogs so these dogs should be isolated if possible until the shedding has stopped. Some dogs can continue to test positive for distemper for an unknown period after treatment. This is most likely because the dog remains in an environment where re-infection keeps occurring.

ClueJay Dog Stool Test Levels 1, 2, and 3 include a reference lab stool O&P (fecal ova and parasites) which screens for roundworms, hookworms, tapeworms, whipworms, and some types of coccidia. Viruses (like distemper virus) and bacteria are not visible on this type of test which is why PCR testing (ClueJay Dog Stool Test Level 3) is needed.

My Dog Tested Negative for Distemper?

ClueJay Dog Stool Test Level 3 includes PCR assay tests for disease-causing bacteria, viruses, and protozoa found in dog intestines. One of those viruses is Canine distemper virus. A negative test means distemper RNA was not detected in the stool. That’s great news. No one wants their dog or puppy shedding these viral particles (virions) and maybe putting other dogs at risk of infection.

Most clinically ill dogs shed large amounts of viral particles in their stool, so a “false (incorrect) negative” result is unlikely if the dog is showing symptoms. Shedding may not have started if early in infection (first few days) or have stopped if late in the course of infection. These are situations where a PCR test could come back negative (falsely), but the dog or puppy was truly infected with distemper. Dogs negative on distemper virus by PCR but still with distemper-like symptoms such as abnormal stools or respiratory symptoms, may have, or have had distemper, but more likely have a different explanation for the symptoms. Please consult with a veterinarian if this is the situation with your dog.

Important: Dogs or puppies with symptoms suspicious of distemper infection should consult with a veterinarian right away! Distemper infections can mimic many other illnesses like “kennel cough” (eye/nose drainage, coughing, sneezing) or intestinal parasite infections (soft stools, bloody diarrhea) during the first phase of infection. Early treatment can sometimes be the difference between life and death, especially in young dogs (3 to 6 months of age) that are unvaccinated or incompletely vaccinated.

Depending on their lifestyle, dogs can remain at risk of distemper exposure so a negative test result today doesn’t mean it couldn’t be positive later.

Sources

  1. VCA Hospitals, Distemper in Dogs
  2. American Veterinary Medical Association, Canine Distemper
  3. WebMD, Canine Distemper
  4. American Kennel Club, Distemper in Dogs
  5. America Animal Hospital Association, Core Vaccinations
  6. The Merck Veterinary Manual (online), Kate E. Creevy, 2013, Overview of Canine Distemper: Veterinary Professionals: Generalized Conditions: Canine Distemper
  7. Green Infectious Diseases of the Dog and Cat: Canine Distemper, 3rd ed. St. Louis, Elsevier Saunders 2006, pp. 25-41
  8. BMC Veterinary Research, Diversity of susceptible hosts in canine distemper virus infection: a systematic review and data synthesis

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