Distemper

Question 1

What type of virus is this?

Answer 1

Paramyxoviridae-enveloped

Question 2

How prevalent is this?

Answer 2

Worldwide, super contagious, affects a large number of animals where dogs are the reservoir

Question 3

How is it transmitted?

Answer 3

Inhaled or ingested via oronasal

Question 4

What is phase 1?

Answer 4

Replication in the lymphoid tissue of the respiratory tract, which includes macrophages and bronchial lymph nodes

Question 5

What is Phase 2?

Answer 5

viremia spreading after 1-5 days and extending to all lymphoid tissues

Question 6

What happens if it is severe?

Answer 6

Depletion of vascular CD3+ T cells and CD21+ B cells along with necrosis and depletion of lymph node cortical areas

Question 7

What are the two main events that happen with distemper?

Answer 7

Immune suppression and leukopenia

Question 8

What type of immunity is needed to protect against this?

Answer 8

Cell mediated AND humoral. Viremia is determined by specific humoral response during that period. If no neutralizing antibodies, the virus will spread.

Question 9

What is Phase 3?

Answer 9

Also called mucosal phase because it spreads to respiratory, GI, urogenital epithelium due to the virus’s pantropic nature. This is when the clinical signs happen

Question 10

What are the clinical signs?

Answer 10

Biphasic fever: if transient, then the disease is subclinical but once the second fever comes, they will have clinical signs like serous nasal discharge, mucopurulent ocular discharge.

Question 11

When are neuro signs seen?

Answer 11

During a longer course of the disease; can see encephalomyelitis, localized muscle twitching/myoclonus, and chewing gum fits. After systemic infection can see seizures and ataxia from cerebellar effects and posterior paralysis from spinal cord effects. Acute is 2-3 weeks after infection and subacute is 2-12 weeks.

Question 12

What is the pathogenesis of acute CNS infection?

Answer 12

it targets neurons and glial cells and leads to grey matter disease (neuronal degeneration and inflammation)

Question 13

What’s the pathogenesis of subacute CNS infection?

Answer 13

Targets oligodendrocytes and leads to a down regulation of myelin (white matter disease)

Question 14

What’s the typical CNS disease?

Answer 14

Mix of grey and white matter

Question 15

What is chronic distemper encephalitis?

Answer 15

Also called old dog, can be seen in vx old dogs with no infection, the antigen is detected in the brain but it is noninfectious and caused by an inflammatory reaction

Question 16

What happens after infection?

Answer 16

Cutaneous hyperkeratosis: hard pad disease of the foot and calluses on the nose. Enamel hypoplasia since it targets ameloblasts.

Question 17

What lesions can be seen?

Answer 17

Bronchopneumonia, enteritis, pustular dermatitis, interstitial pneumonia. Neuronal degeneration and inclusion bodies of the glial cells and neurons

Question 18

How is this diagnosed?

Answer 18

Febrile dogs with multisystemic lesions, unvax dogs between 3 and 6 months mostly affected.

Question 19

What has the highest viral loads and would be good for samples?

Answer 19

Urine, tonsils, conjunctival swabs, whole blood

Question 20

What’s the prognosis?

Answer 20

Supportive therapy but poor if dogs show acute, progressive, severe neuro signs.

Question 21

What about prevention?

Answer 21

Core vaccine, MLV that should not be used in pregnant or lactating dogs. Recomb canarypox vx for ferrets and zoo species.