Topic 65 - Canine distemper Flashcards
What is canine distemper?
It is a contagious and serious disease, attacking the the respiratory, gastrointestinal, and nervous systems of dogs
Occurence of canine distemper:
Worldwide
Causative agent for canine distemper:
canine distemper virus genus
Canine morbillivirus family
How many serotypes for canine distemper:
1
How many genotypes for canine distemper:
7
But they do not influence the immune response
Resistance of canine distemper:
LOW, because the paramyxovirus is enveloped
How is canine distemper shed?
Excretes, most importanty in nasal discharge and urine
The discharges will stabilize the virus, and therefore it can survive for a longer time
Host range for canine distemper:
Wide !
- Canidae is the primary host, the maintaining host
- Felidae
- Sea mammals
Important about felidae affected by canine distemper
- House cats can be infected, byt the clinical signs cannot be seen. the virus is self-limiting = the immune response is enough to inhibit the growth of the virus
- Large cats can show clinical signs
How many show asymptomatic infection with canine distemper?
25-75%
When does the shedding of the canine distemper virus start, and how long can it last?
Start at day 7ish, depends on the pathogenesis, and can last for up to 2-3 months !!
At which age is it more common to observe clinical signs for canine distemper?
2-6 months of age.
There is maternal immunity at this time, this is partially due to vaccination and partially due to seroconversion
Pathogenesis of canine distemper:
- Infection through inhalation and per os
- Primary replication in tonsils and lymph nodes in the area of head and neck
- We have a viremia, where the virus replicates in the mononuclear cells damaging the leucocytes and we will see a immunosuppression
(4. Often canine distemper is seen together with other diseases) - The primary target after the viraemia is the respiratory and alimentary tract where the virus replicates in the epithelium and lymphoid tissues and 1st clinical signs appear
- The immune response influences the severity and the spread of the virus ⭢ The body will produce neutralising antibodies from day 7-9
in case of HIGH immune response for canine distemper, what can we observe?
The replication is inhibited, we see healing and the virus disappears and shedding is short
in case of MEDIUM immune response for canine distemper, what can we observe?
There is no inhibition of the replication, but it is limited. We see a persistent infection and the virus causes lesions on the skin, uvea and nervous system
in case of LOW immune response for canine distemper, what can we observe?
There is no inhibition of the replication.
There is a extended virus replication, the virus will get into the CNS system, the respiratory tract and the alimentary tract
If there is a more intensive virus replication of the canine distemper, what can we observe?
- Bacterual complications
- Central nervous system signs, such as encephalitis, demyelination
- Immunopathological effect = this effect is involved in the background of the CNS signs, because of the good immune response
Incubation time for canine distemper:
3-7 days
a short week
Clinical signs for canine distemper:
- Fever due to viraemia
after secondary replication in the mucus membrane, we see clinical signs on the eyes, respiratiry signs, alimentary signs, skin lesions, CNS signs
Clinical signs for canine distemper, on the eyes:
Conjunctivitis, first it is mild, later it becomes mucoid and ⭡lacrimation, which can cause bacterial complications and the conjunctivitis will become purulent
In severe cases:
Uveitis
Retinintis
Blindness
Clinical signs for canine distemper, on respiratory tract:
Dry cough, which later will become wet with bacterial complications
Clinical signs for canine distemper, on alimentary tract:
Vomiting
Diarrhoea
Clinical signs for canine distemper, on the skin:
Pustlues
Hyperkeratosis
Perakeratosis on nose and sole
Clinical signs for canine distemper, on CNS:
1-3 weeks after general clinical signs
Dullness
Spasms
Movement disorders
Lameness
ataxia
If there is a transplacental infection of canine distemper, what can we observe?
Abortion
Stillbirth
Weak puppes
Enamle (teeth) hypoplasia, is a typical malformation
Immunodeficiency
Pathological signs in case of canine distemper:
We typically see inflammation of the upper respiratory tract.
- Enteritis
- Interstitial pneumonia, sometimes.
- Encephalitis
- Demyelination
Histopathological signs in case of canine distemper:
Cytoplasmic inclusion bodies
How to diagnose canine distemper:
Clinical signs, history and pathology + histppathology
We also test for antigen or antibodies with paried serum, since the clincial signs and pathological lesions are not specific to canine distemper
Differential diagnosis of canine distemper:
Kennel cough
Laryngotracheitis
Leptospirosis
Parvovirus
Rabies
Aujeszky
Treatment for canine distemper:
Antibiotics for bacterial complications
Hyperimmune serum
Vaccine as prevention
Type of vaccine(s) given in case of canine distemper:
- Live attenuated - better, but can cause residual virulence = mild clinical signs
- Inactivated - weaker
At what age do we vaccinate against canine distemper?
At 12 and 16 weeks of age
In combination with:
Adenovirus
Parvovirus
Parainfluenza
- sometimes leptospirosis
