Topic 65 - Canine distemper

Question 1

What is canine distemper?

Answer 1

It is a contagious and serious disease, attacking the the respiratory, gastrointestinal, and nervous systems of dogs

Question 2

Occurence of canine distemper:

Answer 2

Worldwide

Question 3

Causative agent for canine distemper:

Answer 3

canine distemper virus genus
Canine morbillivirus family

Question 4

How many serotypes for canine distemper:

Answer 4

1

Question 5

How many genotypes for canine distemper:

Answer 5

7
But they do not influence the immune response

Question 6

Resistance of canine distemper:

Answer 6

LOW, because the paramyxovirus is enveloped

Question 7

How is canine distemper shed?

Answer 7

Excretes, most importanty in nasal discharge and urine

The discharges will stabilize the virus, and therefore it can survive for a longer time

Question 8

Host range for canine distemper:

Answer 8

Wide !

1. Canidae is the primary host, the maintaining host
2. Felidae
3. Sea mammals

Question 9

Important about felidae affected by canine distemper

Answer 9

1. 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
2. Large cats can show clinical signs

Question 10

How many show asymptomatic infection with canine distemper?

Answer 10

25-75%

Question 11

When does the shedding of the canine distemper virus start, and how long can it last?

Answer 11

Start at day 7ish, depends on the pathogenesis, and can last for up to 2-3 months !!

Question 12

At which age is it more common to observe clinical signs for canine distemper?

Answer 12

2-6 months of age.

There is maternal immunity at this time, this is partially due to vaccination and partially due to seroconversion

Question 13

Pathogenesis of canine distemper:

Answer 13

1. Infection through inhalation and per os
2. Primary replication in tonsils and lymph nodes in the area of head and neck
3. 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)
4. 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
5. The immune response influences the severity and the spread of the virus ⭢ The body will produce neutralising antibodies from day 7-9

Question 14

in case of HIGH immune response for canine distemper, what can we observe?

Answer 14

The replication is inhibited, we see healing and the virus disappears and shedding is short

Question 15

in case of MEDIUM immune response for canine distemper, what can we observe?

Answer 15

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

Question 16

in case of LOW immune response for canine distemper, what can we observe?

Answer 16

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

Question 17

If there is a more intensive virus replication of the canine distemper, what can we observe?

Answer 17

1. Bacterual complications
2. Central nervous system signs, such as encephalitis, demyelination
3. Immunopathological effect = this effect is involved in the background of the CNS signs, because of the good immune response

Question 18

Incubation time for canine distemper:

Answer 18

3-7 days
a short week

Question 19

Clinical signs for canine distemper:

Answer 19

1. 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

Question 20

Clinical signs for canine distemper, on the eyes:

Answer 20

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

Question 21

Clinical signs for canine distemper, on respiratory tract:

Answer 21

Dry cough, which later will become wet with bacterial complications

Question 22

Clinical signs for canine distemper, on alimentary tract:

Answer 22

Vomiting
Diarrhoea

Question 23

Clinical signs for canine distemper, on the skin:

Answer 23

Pustlues
Hyperkeratosis
Perakeratosis on nose and sole

Question 24

Clinical signs for canine distemper, on CNS:

Answer 24

1-3 weeks after general clinical signs

Dullness
Spasms
Movement disorders
Lameness
ataxia

Question 25

If there is a transplacental infection of canine distemper, what can we observe?

Answer 25

Abortion
Stillbirth
Weak puppes
Enamle (teeth) hypoplasia, is a typical malformation
Immunodeficiency

Question 26

Pathological signs in case of canine distemper:

Answer 26

We typically see inflammation of the upper respiratory tract.

1. Enteritis
2. Interstitial pneumonia, sometimes.
3. Encephalitis
4. Demyelination

Question 27

Histopathological signs in case of canine distemper:

Answer 27

Cytoplasmic inclusion bodies

Question 28

How to diagnose canine distemper:

Answer 28

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

Question 29

Differential diagnosis of canine distemper:

Answer 29

Kennel cough
Laryngotracheitis
Leptospirosis
Parvovirus

Rabies
Aujeszky

Question 30

Treatment for canine distemper:

Answer 30

Antibiotics for bacterial complications
Hyperimmune serum
Vaccine as prevention

Question 31

Type of vaccine(s) given in case of canine distemper:

Answer 31

1. Live attenuated - better, but can cause residual virulence = mild clinical signs
2. Inactivated - weaker

Question 32

At what age do we vaccinate against canine distemper?

Answer 32

At 12 and 16 weeks of age

In combination with:
Adenovirus
Parvovirus
Parainfluenza
- sometimes leptospirosis