Canine distemper
Encyclopedia
Canine distemper is a viral
disease
that affects animals in the families Canidae
, Mustelidae
, Mephitidae, Hyaenidae, Ailuridae
, Procyonidae
, Pinnipedia, some Viverridae and Felidae
(though not domestic cats
; feline distemper or panleukopenia
is a different virus exclusive to cats). It is most commonly associated with domestic animals such as dogs and ferret
s, although it can infect wild animals as well. It is a single-stranded RNA virus
of the family paramyxovirus
, and thus a close relative of measles
and rinderpest
. Despite extensive vaccination in many regions, it remains a major disease of dogs.
distemperen, meaning to upset the balance of the humors, which is from the Old French
destemprer, meaning to disturb, which is from the Vulgar Latin
distemperare: Latin dis- and Latin temperare, meaning to not mix properly.
(CDV) seems to have appeared more recently, with the first case described in 1905 by French veterinarian Henri Carré. It was first thought to be related to the plague and typhus
, and was attributed to several species of bacteria. It now affects all populations of domestic dog
and some populations of wildlife
. A vaccine was developed in 1950, yet due to limited use, the virus remains prevalent in many populations. The domestic dog has largely been responsible for introducing canine distemper to previously unexposed wildlife, and now causes a serious conservation threat to many species of carnivores
and some species of marsupial
s. The virus contributed to the near-extinction of the black-footed ferret
. It also may have played a considerable role in the extinction of the Thylacine (Tasmanian tiger)
and recurrently causes mortality among African wild dogs
. In 1991, the lion population in Serengeti, Tanzania experienced a 20% decline as a result of the disease. The disease has also mutated to form phocid distemper virus, which affects seal
s.
, and urine
6–22 days after exposure. It can also be spread by food and water contaminated with these fluids. The time between infection and disease is 14 to 18 days, although there can be a fever from three to six days postinfection.
Canine distemper virus tends to orient its infection towards the lymphoid
, epithelial
, and nervous tissues
. The virus initially replicates in the lymphatic tissue of the respiratory tract. The virus then enters the blood stream and infects the respiratory, gastrointestinal, urogenital epithelium
, central nervous system
, and optic nerve
. Therefore, the typical pathologic features of canine distemper include lymphoid depletion (causing immunosuppression
and leading to secondary infections), interstitial pneumonia
, encephalitis
with demyelination, and hyperkeratosis
of foot pads.
The mortality rate of the virus largely depends on the immune status of the infected dogs. Puppies experience the highest mortality rate, where complications such as pneumonia
and encephalitis
are more common. In older dogs that develop distemper encephalomyelitis
, vestibular disease may present.
Around 15% of canine inflammatory central nervous system diseases are a result of CDV.
, a runny nose, and discharge from the eye. This first round of fever typically recedes rapidly within 96 hours, and then a second round of fever begins around the 11th or 12th day and lasts at least a week. Gastrointestinal and respiratory problems tend to follow, which may become complicated with secondary bacterial infections. Inflammation of the brain and spinal cord otherwise known as encephalomyelitis
is either associated with this, subsequently follows, or comes completely independent of these problems. A thickening of the footpads sometimes develops, and vesicularpustular lesions on the abdomen usually develop. Neurological symptoms typically are found in the animals with thickened footpads from the virus. About half of sufferers experience meningoencephalitis
.
, herpes virus, parainfluenza and leptospirosis
been possible. Thus, finding the virus by various methods in the dog's conjunctival cells gives a definitive diagnosis. In older dogs that develop distemper encephalomyelitis, diagnosis may be more difficult since many of these dogs have an adequate vaccination history.
The most reliable test to confirm distemper is a brush border
slide/smear of the bladder transitional epithelium of the inside lining from the bladder, stained with Dif-Quick. These infected cells have inclusions which stain a carmine red color, found in the paranuclear
cytoplasm
readability. About 90% of the bladder cells will be positive for inclusions in the early stages of distemper. This is good for at least the first 21 days from onset of the disease. After this point, it gets harder to detect as the disease progresses further in the stages and the physical clinical signs will become quite obvious.
s against canine distemper for dog
s (ATCvet code: and combinations) and domestic ferrets
, which in many jurisdictions are mandatory for pets. The type of vaccine should be approved for the type of animal being inoculated, or else the animal could actually contract the disease from the vaccine. A dog who has eaten meat infected with rinderpest
can also sometimes receive temporary immunity. Infected animals should be quarantine
d from other dogs for several months due to the length of time the animal may shed the virus. The virus
is destroyed in the environment by routine cleaning with disinfectants, detergents, or drying. It does not survive in the environment for more than a few hours at room temperature (20–25 °C), but can survive for a few weeks in shady environments at temperatures slightly above freezing. It, along with other labile viruses, can also persist longer in serum and tissue debris.
Research and funding for the most part have focused on vaccination rather than on finding a cure for distemper.
An outdated theory that the injuries that occurred were the result of a strictly autoimmune
reaction, the thought being that initially the canine distemper virus was introduced, but then subsequently eliminated. That the cytokines continued to attack and damage healthy tissue in the absence of a current pathogen. Based on that theory, anti-inflammatory and immunosuppressive drugs have been prescribed by some veterinarians in an attempt to bring the effects of the condition under control but this did not succeed.
It was later considered that the action of macrophage
s on infected nerve cells indicated that the autoimmune
reaction was likely a direct consequence of the presence of the virus. Often, owners seek expert help only when the disease is in its advanced stages (nervous phase) due to the non specific earlier signs and prescription of anti-inflammatory drugs (which are usually corticosteroids) undermine the immune system of the animal, allow the proliferation of the virus, and the autoimmune
reaction increases as a means of containment of infected cells.
The first references to suggest effective treatments for similar viruses could be effective for canine distemper arose when studies found that canine distemper was a disease comparable to measles and infected animals could be used to develop new technologies for treatment of measles. The question of whether the reciprocal would be true was resolved when studies assessed the efficacy of traditional treatments for measles, some of which were successfully applied to animals with distemper.
Vitamin A and ribavirin as a treatment of distemper (and measles) are under evaluation and the modes of action remain unexplained. Some experiments suggest that Vitamin A and ribavirin could be effective as a treatment but to date is not commonly employed in practice. Some evidence points to an indirect action, such as confirming there is a reduction in the amounts of vitamin A during infection, pointing to the hypothesis that it is raw material for some mechanism of resistance to infection. That the anti-infective characteristic is not specific to vitamin A is a mystery; however, there was no doubt about its effectiveness in this particular experiment, action mechanisms elucidated or not.
The adoption of ribavirin
as a possible treatment for canine distemper followed the same steps as vitamin A; it was the principle used in cases of subacute sclerosing panencephalitis under measles. The first verification of the effectiveness occurred "in vitro," It was observed that the distemper virus is very susceptible to ribavirin, and 0.02 to 0.05 micromols are needed to induce its mechanism of error catastrophe
and the inhibitory effect on virus replication by 50%.
The main concern in the use of ribavirin was the result of its interaction with the blood-brain barrier
. As the brain is an immunologically privileged area, the concern was the capacity of ribavirin to overcome this barrier. In a study using mice with encephalitis due to measles, it was found that once the virus has become established in the nervous phase, the blood-brain barrier, fails in a way, reducing the restriction to the action of the ribavirin in these areas. The verification of all these results in vivo resulted in an effectiveness of 80% in animals that had already reached the nervous phase of viral infection. The application of ribavirin demands a close monitoring of the animal due the risk of leukopenia
and the ingestion of long-chain tryglicerides (fats) are needed to better absorb the drug and for preservation of gastric tissues, which are quite susceptible to it.
It is widely accepted by the medical and veterinary communities that while possible treatments are still being explored into their efficacy, that prevention using vaccination, is the most reliable way of preventing disease spread among the population.
parainfluenza virus Type 3, have long been suspected as the causative agents of Paget's disease
, a focal destructive disease of bone. Most studies, however, have pointed more directly at CDV and measles. A virus detection technique, in situ RT-PCR, has found CDV in 100% of Paget's disease samples, whereas other virus detection techniques have been less accurate.
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
that affects animals in the families Canidae
Canidae
Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...
, Mustelidae
Mustelidae
Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...
, Mephitidae, Hyaenidae, Ailuridae
Ailuridae
Ailuridae is a family in the mammal order Carnivora. The family includes the Red Panda and its extinct relatives.-Classification history:...
, Procyonidae
Procyonidae
Procyonidae is a New World family of the order Carnivora. It includes the raccoons, coatis, kinkajous, olingos, ringtails and cacomistles. Procyonids inhabit a wide range of environments, and are generally omnivorous.-Characteristics:...
, Pinnipedia, some Viverridae and Felidae
Felidae
Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...
(though not domestic cats
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
; feline distemper or panleukopenia
Feline panleukopenia
Feline panleukopenia virus , also known as Feline infectious enteritis, Feline distemper, feline ataxia, or cat plague, is a viral infection affecting cats, both domesticated and wild feline species. It is caused by feline parvovirus, a close relative of both type 2 canine parvovirus and mink...
is a different virus exclusive to cats). It is most commonly associated with domestic animals such as dogs and ferret
Ferret
The ferret is a domesticated mammal of the type Mustela putorius furo. Ferrets are sexually dimorphic predators with males being substantially larger than females. They typically have brown, black, white, or mixed fur...
s, although it can infect wild animals as well. It is a single-stranded RNA virus
RNA virus
An RNA virus is a virus that has RNA as its genetic material. This nucleic acid is usually single-stranded RNA but may be double-stranded RNA...
of the family paramyxovirus
Paramyxovirus
Paramyxoviruses are viruses of the Paramyxoviridae family of the Mononegavirales order; they are negative-sense single-stranded RNA viruses responsible for a number of human and animal diseases.-Genera:*Subfamily Paramyxovirinae**Genus Avulavirus Paramyxoviruses (from Greek para-, beyond, -myxo-,...
, and thus a close relative of measles
Measles
Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...
and rinderpest
Rinderpest
Rinderpest was an infectious viral disease of cattle, domestic buffalo, and some other species of even-toed ungulates, including buffaloes, large antelopes and deer, giraffes, wildebeests and warthogs. After a global eradication campaign, the last confirmed case of rinderpest was diagnosed in 2001...
. Despite extensive vaccination in many regions, it remains a major disease of dogs.
Etymology
The origin of the word distemper is from the Middle EnglishMiddle English
Middle English is the stage in the history of the English language during the High and Late Middle Ages, or roughly during the four centuries between the late 11th and the late 15th century....
distemperen, meaning to upset the balance of the humors, which is from the Old French
Old French
Old French was the Romance dialect continuum spoken in territories that span roughly the northern half of modern France and parts of modern Belgium and Switzerland from the 9th century to the 14th century...
destemprer, meaning to disturb, which is from the Vulgar Latin
Vulgar Latin
Vulgar Latin is any of the nonstandard forms of Latin from which the Romance languages developed. Because of its nonstandard nature, it had no official orthography. All written works used Classical Latin, with very few exceptions...
distemperare: Latin dis- and Latin temperare, meaning to not mix properly.
History
Although very similar to the measles virus, canine distemper virusVirus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
(CDV) seems to have appeared more recently, with the first case described in 1905 by French veterinarian Henri Carré. It was first thought to be related to the plague and typhus
Typhus
Epidemic typhus is a form of typhus so named because the disease often causes epidemics following wars and natural disasters...
, and was attributed to several species of bacteria. It now affects all populations of domestic dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
and some populations of wildlife
Wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....
. A vaccine was developed in 1950, yet due to limited use, the virus remains prevalent in many populations. The domestic dog has largely been responsible for introducing canine distemper to previously unexposed wildlife, and now causes a serious conservation threat to many species of carnivores
Carnivora
The diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...
and some species of marsupial
Marsupial
Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
s. The virus contributed to the near-extinction of the black-footed ferret
Black-footed Ferret
The Black-footed Ferret , also known as the American polecat or Prairie Dog Hunter, is a species of Mustelid native to central North America. It is listed as endangered by the IUCN, because of its very small and restricted populations...
. It also may have played a considerable role in the extinction of the Thylacine (Tasmanian tiger)
Thylacine
The thylacine or ,also ;binomial name: Thylacinus cynocephalus, Greek for "dog-headed pouched one") was the largest known carnivorous marsupial of modern times. It is commonly known as the Tasmanian tiger or the Tasmanian wolf...
and recurrently causes mortality among African wild dogs
African Wild Dog
Lycaon pictus is a large canid found only in Africa, especially in savannas and lightly wooded areas. It is variously called the African wild dog, African hunting dog, Cape hunting dog, painted dog, painted wolf, painted hunting dog, spotted dog, or ornate wolf...
. In 1991, the lion population in Serengeti, Tanzania experienced a 20% decline as a result of the disease. The disease has also mutated to form phocid distemper virus, which affects seal
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...
s.
Infection
Puppies from three to six months old are particularly susceptible. CDV spreads through aerosol droplets and through contact with infected bodily fluids including nasal and ocular secretions, fecesFeces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
, and urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
6–22 days after exposure. It can also be spread by food and water contaminated with these fluids. The time between infection and disease is 14 to 18 days, although there can be a fever from three to six days postinfection.
Canine distemper virus tends to orient its infection towards the lymphoid
Lymphatic system
The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...
, epithelial
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
, and nervous tissues
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
. The virus initially replicates in the lymphatic tissue of the respiratory tract. The virus then enters the blood stream and infects the respiratory, gastrointestinal, urogenital epithelium
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
, central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
, and optic nerve
Optic nerve
The optic nerve, also called cranial nerve 2, transmits visual information from the retina to the brain. Derived from the embryonic retinal ganglion cell, a diverticulum located in the diencephalon, the optic nerve doesn't regenerate after transection.-Anatomy:The optic nerve is the second of...
. Therefore, the typical pathologic features of canine distemper include lymphoid depletion (causing immunosuppression
Immunosuppression
Immunosuppression involves an act that reduces the activation or efficacy of the immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other...
and leading to secondary infections), interstitial pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
, encephalitis
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
with demyelination, and hyperkeratosis
Hyperkeratosis
Hyperkeratosis is thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin, and also usually accompanied by an increase also in the granular layer...
of foot pads.
The mortality rate of the virus largely depends on the immune status of the infected dogs. Puppies experience the highest mortality rate, where complications such as pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
and encephalitis
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
are more common. In older dogs that develop distemper encephalomyelitis
Encephalomyelitis
Encephalomyelitis is a general term for inflammation of the brain and spinal cord, describing a number of disorders:* Acute disseminated encephalomyelitis or postinfectious encephalomyelitis, a demyelinating disease of the brain and spinal cord, possibly triggered by vaccination or viral...
, vestibular disease may present.
Around 15% of canine inflammatory central nervous system diseases are a result of CDV.
Disease progression
The virus first appears in bronchial lymph nodes and tonsils two days after exposure. The virus then enters the blood stream on the second or third day. A first round of acute fever tends to begin around 3 to 8 days after infection, which is often accompanied by a low white blood cell count, especially of lymphocytes, as well as low platelet count. These signs may or may not be accompanied by anorexiaAnorexia (symptom)
Anorexia is the decreased sensation of appetite...
, a runny nose, and discharge from the eye. This first round of fever typically recedes rapidly within 96 hours, and then a second round of fever begins around the 11th or 12th day and lasts at least a week. Gastrointestinal and respiratory problems tend to follow, which may become complicated with secondary bacterial infections. Inflammation of the brain and spinal cord otherwise known as encephalomyelitis
Encephalomyelitis
Encephalomyelitis is a general term for inflammation of the brain and spinal cord, describing a number of disorders:* Acute disseminated encephalomyelitis or postinfectious encephalomyelitis, a demyelinating disease of the brain and spinal cord, possibly triggered by vaccination or viral...
is either associated with this, subsequently follows, or comes completely independent of these problems. A thickening of the footpads sometimes develops, and vesicularpustular lesions on the abdomen usually develop. Neurological symptoms typically are found in the animals with thickened footpads from the virus. About half of sufferers experience meningoencephalitis
Meningoencephalitis
Meningoencephalitis is a medical condition that simultaneously resembles both meningitis, which is an infection or inflammation of the meninges, and encephalitis, which is an infection or inflammation of the brain.-Causes:...
.
Gastrointestinal and respiratory symptoms
Commonly observed signs are a runny nose, vomiting and diarrhea, dehydration, excessive salivation, coughing and/or labored breathing, loss of appetite, and weight loss. When and if the neurological symptoms develop, incontinence may ensue.Neurological symptoms
The symptoms within the central nervous system include a localized involuntary twitching of muscles or groups of muscles, seizures often distinguished by salivation, and jaw movements commonly described as "chewing gum fits", or more appropriately as "distemper myoclonus". As the condition progresses, the seizures worsen and advance to grand mal convulsions, followed by death of the animal. The animal may also show signs of sensitivity to light, incoordination, circling, increased sensitivity to sensory stimuli such as pain or touch, and deterioration of motor capabilities. Less commonly, it may lead to blindness and paralysis. The length of the systemic disease may be as short as 10 days, or the start of neurological symptoms may not come until several weeks or months later. Those few that survive usually have a small tic or twitch of varying levels of severity. With time, this tic will usually diminish somewhat in its severity.Diagnosis
The above symptoms, especially fever, respiratory signs, neurological signs, and thickened footpads found in unvaccinated dogs strongly indicate canine distemper. However, several febrile diseases match many of the symptoms of the disease and only recently has distinguishing between canine hepatitisHepatitis
Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...
, herpes virus, parainfluenza and leptospirosis
Leptospirosis
Leptospirosis is caused by infection with bacteria of the genus Leptospira, and affects humans as well as other mammals, birds, amphibians, and reptiles.The...
been possible. Thus, finding the virus by various methods in the dog's conjunctival cells gives a definitive diagnosis. In older dogs that develop distemper encephalomyelitis, diagnosis may be more difficult since many of these dogs have an adequate vaccination history.
The most reliable test to confirm distemper is a brush border
Brush border
A brush border is the name for the microvilli-covered surface of simple cuboidal epithelium and simple columnar epithelium cells found in certain locations of the body. Microvilli are approximately 100 nanometers in diameter and their length varies from approximately 100 to 2,000 nanometers in...
slide/smear of the bladder transitional epithelium of the inside lining from the bladder, stained with Dif-Quick. These infected cells have inclusions which stain a carmine red color, found in the paranuclear
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
readability. About 90% of the bladder cells will be positive for inclusions in the early stages of distemper. This is good for at least the first 21 days from onset of the disease. After this point, it gets harder to detect as the disease progresses further in the stages and the physical clinical signs will become quite obvious.
Prevention
There exist a number of vaccineVaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s against canine distemper for dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s (ATCvet code: and combinations) and domestic ferrets
Ferret
The ferret is a domesticated mammal of the type Mustela putorius furo. Ferrets are sexually dimorphic predators with males being substantially larger than females. They typically have brown, black, white, or mixed fur...
, which in many jurisdictions are mandatory for pets. The type of vaccine should be approved for the type of animal being inoculated, or else the animal could actually contract the disease from the vaccine. A dog who has eaten meat infected with rinderpest
Rinderpest
Rinderpest was an infectious viral disease of cattle, domestic buffalo, and some other species of even-toed ungulates, including buffaloes, large antelopes and deer, giraffes, wildebeests and warthogs. After a global eradication campaign, the last confirmed case of rinderpest was diagnosed in 2001...
can also sometimes receive temporary immunity. Infected animals should be quarantine
Quarantine
Quarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....
d from other dogs for several months due to the length of time the animal may shed the virus. The virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
is destroyed in the environment by routine cleaning with disinfectants, detergents, or drying. It does not survive in the environment for more than a few hours at room temperature (20–25 °C), but can survive for a few weeks in shady environments at temperatures slightly above freezing. It, along with other labile viruses, can also persist longer in serum and tissue debris.
Treatment
Until recently, canine distemper has been associated with a long history of pessimism with respect to treatment of infected animals and the disease was usually assumed to have a poor prognosis. Most care offered was only palliative, geared toward easing the suffering. Several factors had an important role in maintaining the status quo.Research and funding for the most part have focused on vaccination rather than on finding a cure for distemper.
An outdated theory that the injuries that occurred were the result of a strictly autoimmune
Autoimmunity
Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which allows an immune response against its own cells and tissues. Any disease that results from such an aberrant immune response is termed an autoimmune disease...
reaction, the thought being that initially the canine distemper virus was introduced, but then subsequently eliminated. That the cytokines continued to attack and damage healthy tissue in the absence of a current pathogen. Based on that theory, anti-inflammatory and immunosuppressive drugs have been prescribed by some veterinarians in an attempt to bring the effects of the condition under control but this did not succeed.
It was later considered that the action of macrophage
Macrophage
Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...
s on infected nerve cells indicated that the autoimmune
Autoimmunity
Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which allows an immune response against its own cells and tissues. Any disease that results from such an aberrant immune response is termed an autoimmune disease...
reaction was likely a direct consequence of the presence of the virus. Often, owners seek expert help only when the disease is in its advanced stages (nervous phase) due to the non specific earlier signs and prescription of anti-inflammatory drugs (which are usually corticosteroids) undermine the immune system of the animal, allow the proliferation of the virus, and the autoimmune
Autoimmunity
Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which allows an immune response against its own cells and tissues. Any disease that results from such an aberrant immune response is termed an autoimmune disease...
reaction increases as a means of containment of infected cells.
The first references to suggest effective treatments for similar viruses could be effective for canine distemper arose when studies found that canine distemper was a disease comparable to measles and infected animals could be used to develop new technologies for treatment of measles. The question of whether the reciprocal would be true was resolved when studies assessed the efficacy of traditional treatments for measles, some of which were successfully applied to animals with distemper.
Vitamin A and ribavirin as a treatment of distemper (and measles) are under evaluation and the modes of action remain unexplained. Some experiments suggest that Vitamin A and ribavirin could be effective as a treatment but to date is not commonly employed in practice. Some evidence points to an indirect action, such as confirming there is a reduction in the amounts of vitamin A during infection, pointing to the hypothesis that it is raw material for some mechanism of resistance to infection. That the anti-infective characteristic is not specific to vitamin A is a mystery; however, there was no doubt about its effectiveness in this particular experiment, action mechanisms elucidated or not.
The adoption of ribavirin
Ribavirin
Ribavirin is an anti-viral drug indicated for severe RSV infection , hepatitis C infection and other viral infections. Ribavirin is a prodrug, which when metabolised resembles purine RNA nucleotides...
as a possible treatment for canine distemper followed the same steps as vitamin A; it was the principle used in cases of subacute sclerosing panencephalitis under measles. The first verification of the effectiveness occurred "in vitro," It was observed that the distemper virus is very susceptible to ribavirin, and 0.02 to 0.05 micromols are needed to induce its mechanism of error catastrophe
Error catastrophe
Error catastrophe is a term used to describe the extinction of an organism as a result of excessive RNA mutations. The term specifically refers to the predictions of mathematical models similar to that described below, and not to an observed phenomenon.Like every organism, viruses 'make mistakes'...
and the inhibitory effect on virus replication by 50%.
The main concern in the use of ribavirin was the result of its interaction with the blood-brain barrier
Blood-brain barrier
The blood–brain barrier is a separation of circulating blood and the brain extracellular fluid in the central nervous system . It occurs along all capillaries and consists of tight junctions around the capillaries that do not exist in normal circulation. Endothelial cells restrict the diffusion...
. As the brain is an immunologically privileged area, the concern was the capacity of ribavirin to overcome this barrier. In a study using mice with encephalitis due to measles, it was found that once the virus has become established in the nervous phase, the blood-brain barrier, fails in a way, reducing the restriction to the action of the ribavirin in these areas. The verification of all these results in vivo resulted in an effectiveness of 80% in animals that had already reached the nervous phase of viral infection. The application of ribavirin demands a close monitoring of the animal due the risk of leukopenia
Leukopenia
Leukopenia is a decrease in the number of white blood cells found in the blood, which places individuals at increased risk of infection....
and the ingestion of long-chain tryglicerides (fats) are needed to better absorb the drug and for preservation of gastric tissues, which are quite susceptible to it.
It is widely accepted by the medical and veterinary communities that while possible treatments are still being explored into their efficacy, that prevention using vaccination, is the most reliable way of preventing disease spread among the population.
Relation to Paget's disease
Paramyxoviruses, such as CDV, measles, respiratory syncytial virus, simian virus 5, andparainfluenza virus Type 3, have long been suspected as the causative agents of Paget's disease
Paget's disease of bone
Paget's disease is a chronic disorder that can result in enlarged and misshapen bones. The excessive breakdown and formation of bone tissue causes affected bone to weaken, resulting in pain, misshapen bones, fractures, and arthritis in the joints near the affected bones...
, a focal destructive disease of bone. Most studies, however, have pointed more directly at CDV and measles. A virus detection technique, in situ RT-PCR, has found CDV in 100% of Paget's disease samples, whereas other virus detection techniques have been less accurate.