distemper

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Dog suffering from distemper with purulent nasal discharge and hyperkeratosis of the nasal surface

The distemper is a viral disease that for centuries in domestic dogs is known. Distemper has already been observed in the following families: dogs (Canidae) , cats , hyenas , martens , small bears , small pandas , bears and crawling cats . It can also occur in skunks and seals . It is also called Carré's disease , in English as (canine) distemper , after the discoverer of its pathogen, Henri Carré . The disease is characterized by a high fever and fatigue. Depending on the organ system involved, diarrhea and vomiting or respiratory symptoms can occur. In the further course, damage to the brain with central nervous symptoms can occur.

Until vaccination was introduced in the 1960s, distemper was one of the most damaging canine diseases in Germany. Since the 1980s, however, an increase in the virus disease has been observed again, which is related to increasing vaccination fatigue and dog imports from Eastern Europe.

Pathogen

The disease is caused by the canine distemper virus (CDV, Canine Distemper Virus triggered). The pathogen is a morbillivirus from the Paramyxoviridae family . It is closely related to the measles virus in humans, the bovine rinderpest virus and the seal congestion virus, which was responsible for the massive deaths of seals in the North Sea in 1988 . Outside the living organism of the pathogen remains just days infectious . While it is quite resistant to drying and cold, it is very quickly inactivated by all common disinfectants .

Pathogenesis

Histological specimen from the lungs of an African wild dog with distemper. A: Obstructed bronchiole with surrounding lymphocytic infiltrate. B: Detail with recognizable inclusion bodies due to the incorporation of virus proteins. ( HE staining )

The disease mainly affects young dogs between eight weeks and six months of age. The incubation period is usually between three and seven days. After the virus has been absorbed through the lining of the mouth or nose, it first multiplies in the tonsils or bronchial lymph nodes. Four days after infection, viraemia occurs , as a result of which tissues of the immune system such as the spleen , thymus , bone marrow , lymph nodes or Kupffer cells are colonized. If the body can produce sufficient antibodies within the first nine days , symptoms of the disease will generally not develop. If the formation of antibodies does not occur, the pathogen affects the digestive and nervous systems as well as the respiratory system and the urogenital tract. Since from this point onwards all secretions and excretions of the dog contain viral material, the disease can spread through the population.

Course of disease

Young wolf with distemper at an advanced stage, recovered from Abruzzo in early 2013 ; died despite symptomatic treatment. The wolf had bloody diarrhea, among other symptoms.

Depending on the affected organs, different forms of progression are observed, but they can also occur in combination. What they all have in common is the occurrence of high fever, which can rise to 41 ° C, as well as loss of appetite and apathy .

If these two forms remain, the disease takes a comparatively mild course and often leads to recovery after two to four weeks. However, if the nervous system is affected, the prognosis is much less favorable and often ends with the death of the animal.

Hyperkeratoses in the area of ​​the balls of the feet and the nasal surface, the so-called hard pad disease , are associated with severe forms . It is to be assessed as a prognostically unfavorable sign. Since the viruses also attack the cells responsible for tooth formation ( adamantoblasts ), after an infection that has survived in puppyhood, it is not uncommon for a stagnant bite to occur, which is characterized by extensive defects in the dog's tooth enamel .

As a long-term consequence of a congestion infection, older dogs can rarely develop a chronic, progressive inflammation of the brain ( encephalitis ); one speaks of Old Dog Encephalitis (ODE). In such dogs, the distemper virus can persist in the brain for reasons not fully understood, causing progressively worsening neurological symptoms. Viruses are not excreted, so that such dogs are not contagious to other dogs.

In minks, ferrets and raccoons, the infection is usually fatal.

diagnosis

The diagnosis of distemper is extremely difficult. Clinical suspicion can be expressed if there are corresponding symptoms and a missing or incomplete primary vaccination course. Serological tests are of no importance in vaccinated animals, as it is not possible to differentiate between antibodies of infection and vaccination. Direct detection of the virus in the blood can be negative in the late phase of the infection when the viremic phase has already passed. The most reliable diagnosis can be made in living animals by detecting the virus RNA using RT-PCR in the blood and cerebrospinal fluid . Since the viral load is significantly higher during an infection than after a vaccination, a quantitative RT-PCR can also be used to detect an infection in vaccinated dogs; false positive results can only occur in the initial stage of an infection. In late forms after surviving epithelial manifestation, the virus detection in the urine or in the cerebral fluid is most useful to confirm the diagnosis.

In dead animals, the diagnosis can be made on the basis of vacuolization, i.e. the formation of vacuoles , in the neuropil as well as by the detection of eosinophilic inclusion bodies in the nucleus (intranuclear) of glial cells or in the epithelial cells of the digestive, respiratory or urinary tract.

treatment

Treatment can only be symptomatic; the administration of antivirals is not established. Usually antibiotics to fight secondary bacterial infections as well as cough suppressants and expectorants are administered. In the case of diarrhea with dehydration, it is advisable to give fluids. Euthanasia should be considered in severe neurological deficits.

prophylaxis

Vaccinations are the most important prophylaxis , precisely because the disease has increased again in recent years. Therefore, dogs should be protected with a primary vaccination followed by a booster vaccination. Because puppies are often protected by maternal antibodies for a very long time , the right time to start a primary vaccination may vary. The Standing Vaccination Commission vet. recommends, however, a first vaccination for young dogs at the age of eight weeks, a second vaccination four weeks later and the third vaccination at 16 weeks as well as a booster after 15 months. From the age of two, a refresher every three years is sufficient. If a puppy is only vaccinated for the first time after twelve weeks of life, two vaccinations every three to four weeks and a booster after another year for basic immunization are sufficient. There are now also vaccines such. B. Nobivac SHP , in which a vaccination from 12 weeks of age is sufficient for the primary vaccination and is then repeated every three years.

A special form is post-vaccinal distemper encephalitis that occurs after a vaccination . Here the disease breaks out three days to three weeks after a vaccination. Animals up to six months of age are particularly affected. Causes are a latent congestion infection that already exists at the time of vaccination, an increased susceptibility to infection or, rarely, an insufficient weakening of the vaccine.

Ferrets can be vaccinated against distemper from the age of ten weeks. An annual vaccination is considered sufficient here.

Strict hygiene is required when dealing with sick animals in order to prevent the virus from spreading. Treatment with serum antibodies and interferons is used for therapy; infusions and the administration of antibiotics are indicated for concomitant and secondary diseases .

In cases where a litter is exposed to high infection pressure, it is possible to vaccinate the puppies with human measles vaccine from the age of six weeks . Due to the close relationship between distemper and measles viruses, this vaccination offers protection against clinical distemper: Due to the slightly different antigens , the vaccine is not inactivated in any noteworthy manner by the maternal antibodies still present at this point in time and thus stimulates the development of an immune response, which is also clinically effective against the distemper virus. The experimental infection of dogs with measles viruses also leads to the development of immunity to distemper.

Web links

Commons : Distemper  - collection of images, videos and audio files

Individual evidence

  1. ↑ Sharon L. Deem, Lucy H. Spelman, Rebecca A. Yates, and others. a .: Canine distemper in terrestrial carnivores: a review. In: Journal of Zoo and Wildlife Medicine. 31, 2000, pp. 441-451, doi : 10.1638 / 1042-7260 (2000) 031 [0441: CDITCA] 2.0.CO; 2 .
  2. ↑ H. Carré. Sur la maladie des jeunes chiens In: Comptes rendus de l'académie des sciences [III]. 1905, 140, pp. 689-690 and 1489-1491.
  3. ↑ a b c d Nadine Hagendorf et al .: Vaccination fatigue and detection hurdles - challenges in distemper . In: kleintier specifically 18 (2015), issue 4, pp. 2–7. doi : 10.1055 / s-0035-1550140
  4. ↑ Daria Di Sabatino, Alessio Lorusso, Cristina E. Di Francesco, Leonardo Gentile, Vincenza Di Pirro, Anna Lucia Bellacicco, Armando Giovannini, Gabriella Di Francesco, Giuseppe Marruchella, Fulvio Marsilio, Giovanni Savini, Sergios-Orestis Kolokotronis: Arctic Lineage-Canine Distemper Virus as a Cause of Death in Apennine Wolves (Canis lupus) in Italy. In: PLoS ONE. 9, 2014, p. E82356, doi : 10.1371 / journal.pone.0082356 .
  5. ^ The Merck Veterinary Manual: Canine Distemper
  6. ↑ Andreas Moritz among others: Assessment of diagnostic possibilities in the canine distemper virus infection. In: Small Animal Practice. 43 (1998), pp. 153-172.
  7. ↑ TB Saito et al .: Detection of canine distemper virus by reverse transcription-polymerase chain reaction in the urine of dogs with clinical signs of distemper encephalitis . In: Res Vet Science, 80: 116-119, 2006.
  8. ↑ Vaccination recommendation of the Standing Vaccination Commission vet. for dogs
  9. ↑ Vaccination recommendation of the Standing Vaccination Commission vet. for ferrets
  10. ↑ WS Chalmers, W. Baxendale: A comparison of canine distemper vaccine and measles vaccine for the prevention of canine distemper in young puppies In: Vet. Rec. 135, 1994, pp. 349-353. PMID 7846822
  11. ^ RA Moura, J. Warren: Subclinical infection of dogs by canine-adapted measles virus evidenced by their subsequent immunity to canine distemper virus. In: J. Bacteriol. 82, 1961, pp. 702-705. PMID 14476677 PMC 279238 (free full text)