Difference between revisions of "Canine Distemper Virus"
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==Description== | ==Description== | ||
− | Canine distemper is a contagious, febrile disease of canids and other carnivores caused by Canine Distemper Virus. Canine distemper virus is a member of the | + | Canine distemper is a contagious, febrile disease of canids and other carnivores caused by Canine Distemper Virus. Canine distemper virus is a member of the Paramyxoviridae family and the morbillivirus genus, and as such is closely related to the measles, rinderpest and phocine and dolphin distemper viruses. The Paramyxoviridae have a helical nucleocapsid surrounded by an envelope which possesses spiked glycoproteins responsible for haemagglutinin, neuraminidase and haemolytic activities. The genome of the Paramyxoviridae is single-stranded, negative-sense RNA which is used as a template for the production of messenger (posititce-sense) RNA and further genomic material. Paramyxoviridae are sensitive to heat, dessication and most disinfectants, and so are not resistant in the environment. |
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*[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]] | *[[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|Rhinitis]] |
Revision as of 14:50, 12 August 2010
This article is still under construction. |
Description
Canine distemper is a contagious, febrile disease of canids and other carnivores caused by Canine Distemper Virus. Canine distemper virus is a member of the Paramyxoviridae family and the morbillivirus genus, and as such is closely related to the measles, rinderpest and phocine and dolphin distemper viruses. The Paramyxoviridae have a helical nucleocapsid surrounded by an envelope which possesses spiked glycoproteins responsible for haemagglutinin, neuraminidase and haemolytic activities. The genome of the Paramyxoviridae is single-stranded, negative-sense RNA which is used as a template for the production of messenger (posititce-sense) RNA and further genomic material. Paramyxoviridae are sensitive to heat, dessication and most disinfectants, and so are not resistant in the environment.
- Rhinitis
- Although many organs can be affected by CDV, a relatively constant feature is the respiratory signs which occur in varying severity
- A syndrome of catharral oculonasal discharge, pharyngitis and bronchitis is relatively common in the initial stages
- Since one of the primary sites of action of this virus is lymphoid tissue, the resultant immunosuppression -> predisposition to secondary bacterial infection
- May cause interstitial pneumonia where inclusions are found within alveolar macrophages
- Gross pathology:
- Oedematous lungs, diffuse interstitial pneumonia
- Micro pathology:
- Necrosis of pneumocytes, necrotising bronchiolitis, alveolar oedema, thickening of alveolar walls and type II pneumocyte hyperplasia
Aerosol infection
- Infects alveolar macrophages or oropharynx
- Multiplies in the bronchial and other lymph nodes, infects monocytes and dendritic cells
- Viraemia
- Spreads via monocytes to a variety of epithelium depending upon the strain of virus
- Respiratory and alimentary tracts, skin and later (1-5 wk. post infection) to the brain
- Clinical signs:
- Mucopurulent oculonasal discharge
- Keratitis
- Interstitial pneumonia
- Severe clinical pneumonia follows secondary infection with Bordetella bronchiseptica
- Smelly sometimes bloody diarrhoea
- Eruptions on the skin including hyperkeratosis of the nose and pads (hardpad)
- Demyelination (especially in cerebellum) -> incoordination or muscle tremors -> paralysis and coma or convulsions -> death
- Encephalitis
- Secondary pyogenic infections associated with immunosuppression and damage to epithelia
- Recovered animals may have persistent or spasmodic chorea
- The severity of the disease may vary; if enough neutralising antibody develops in the early stages, the virus maybe kept restricted largely to the lymph nodes
- Variable mortality depending on virulence
- May occur subclinically
- Involvement of central nervous system generally results in death
- Can contribute to Infectious Canine Tracheitis
- May be involved in chronic interstitial pancreatitis
- May cause growth retardation lattice
- May also trigger latent Toxoplasmosis due to suppressing effect on lymphoid tissue
Signalment
- Dogs, ferrets, seals, lions, mink
- Has been a major pathogen of dogs prior to vaccination
Diagnosis
- May present as series of infections
- Immunocytochemistry of inclusion bodies
- Intracytoplasmic inclusions may be found in most affected tissues
- Inclusions persist longest in the brain (may be intranuclear) and the alveolar macrophages
- Sections of fixed bronchial tissue, lung, macrophages, bladder may be used or nasal or conjunctival epithelium from live animals
- Giant cells may be seen in the alveol
Clinical Signs
Laboratory Tests
Diagnostic Imaging
Pathology
Treatment
- Live attenuated virus vaccines given at 10 and 12 weeks of age
- Some now given at 7 and 10 weeks to allow socialisation
- Homeopathic vaccines do not work
- Live attenuated vaccines may kill some wildlife therefore Iscom vaccine is used in seal sanctuaries