Distemper virus Flashcards
(13 cards)
What is canine distemper and which virus causes it?
Canine distemper is caused by canine distemper virus (CDV), an enveloped single-stranded RNA virus of the genus Morbillivirus, related to measles virus.
How has vaccination affected the prevalence of canine distemper?
Since modified live vaccines were introduced in the 1960s, prevalence has dropped significantly. Recent slight increases in USA and Europe due to reduced vaccination rates and vaccine breakdown.
What species are susceptible to canine distemper?
Affects dogs, foxes, ferrets, mink, otters, badgers, raccoons, large cats, seals (phocid distemper), and historically contributed to extinction events like the black-footed ferret and Tasmanian tiger.
How is canine distemper transmitted?
Mainly by inhalation and direct dog-to-dog contact. Virus shedding starts 7 days post-infection. No carrier state but virus can persist in CNS for long periods.
Describe the pathogenesis of canine distemper infection.
Replicates in macrophages, lymphoid cells, epithelial cells, and neurons. Viraemia occurs ~2 days post-infection. Lymphocytolysis leads to immunosuppression, aiding spread to epithelial tissues.
What factors influence the clinical signs of canine distemper?
Strain variation, host immune response, tissue tropism. Strong T-cell response helps recovery. Breed sensitivity noted, e.g. Rottweilers more susceptible.
What are the clinical signs of canine distemper?
Variable: pyrexia, depression, nasal/ocular discharge, vomiting, diarrhoea, ‘hard pad’, weight loss, CNS signs, dental enamel hypoplasia, secondary infections (e.g. kennel cough).
Describe the delayed neurological manifestations of canine distemper.
Virus can persist in CNS causing encephalitis months to years later, even without prior signs. Transplacental infection can cause stillbirths or puppies with neurological signs.
How is canine distemper diagnosed?
Histopathology (inclusion bodies), PCR (buffy coat, conjunctival smears), immunocytochemistry, CSF analysis, serology (IgM and IgG titres). PCR is the most sensitive method in acute cases.
What is the treatment for canine distemper?
No antiviral exists. Supportive therapy includes antibiotics for secondary infections, fluids, nursing care, anticonvulsants for neurological cases. Prognosis poor if progressive CNS signs.
Describe the vaccination strategies for canine distemper.
Modified live vaccines (Ondestepoort strain in UK). Historically Rockborn strain used (withdrawn due to encephalitis risk). UK vaccines licensed for 3-year intervals; ferrets also vaccinated.
What infection control measures help prevent canine distemper?
Disinfection and good hygiene in kennels and rescue centres. CDV is highly susceptible to heat, light, and disinfectants, and does not survive long outside the body.
