26. Canine herpesviral disease.

Question 1

Causative agent and occurrence?

Answer 1

Herpesvirus infection of dogs

• Severe, mainly lethal, generalised disease of dog pups
• Causative agent: Canid herpesvirus 1 (CaHV-1) (Alphaherpesvirinae)
• World-wide distribution, frequent seropositivity ʹ average 6%, in kennel 30-100%
• Isolation on canine kidney cells
• Dog & other canids are susceptible
• Optimal temp for viral polymerase is 33-35oC (temp sensitive virus)
• Serological diagnosis made by virus neutralisation test

Question 2

Pathogenesis?

Answer 2

Question 3

Clinical signs?

Answer 3

Clinical signs:

• (usually up to 3 weeks of age)- not characteristic
• Most obvious characteristic is that the puppies die one after the other
• Foetal row: puppies of different ages will be aborted
• Depression, weight loss, abdominal discomfort, yellowish faeces, reduced suckling
• Crying, restlessness, trembling, rhinitis
• Necrotising vasculitis, haemorrhages, rash, pustules, oedema
• Opisthotonus, convulsions, coma death
• W/in 1-2 days; under 1 week of age ~80% mortality
• Convalescent pups may have permanent CNS lesions (vision, motion)
• Adult dogs
• Usually asymptomatic
• Rarely resp signs ~ kennel cough
• Pustules, haemorrhages on the genital mucosae
• Bitch ʹ abortion, stillbirth, (transient) infertility
• In the winter ʹ keep puppies in warm places to stop the replication of the virus!
• owner should also expect serial death of the puppies (chances of treatment is low if death has already occurred)

Question 4

Pathology, Histopathology?

Answer 4

Pathology, histopathology:

• Generalised haemorrhages, oedema, necrosis (liver, spleen, brain, lungs)
• Perivascular necrosis, reactive lymphoid hyperplasia, nuclear inclusions
• (Signs are characteristic only in foetuses/puppies ʹ -adults dont die due to herpesvirus)

Question 5

Diagnosis?

Answer 5

Diagnosis:

• clinical signs,
• lab findings (elevated ALT, thrombocytopenia),
• isolation, PCR, serology: VN

Question 6

DD?

Answer 6

Differential diagnosis:

• fading puppies (CPV-1, CPV-2),
• general signs (CDV, CAdV-1)

Question 7

Treatment?

Answer 7

Treatment

• usually not successful
• Hyperimmune serum (1-2ml, I.P., in early stage) ʹ rarely used these days
• Antivirals: Acyclovir - 10mg PO in 6h intervals until 3.5 weeks if age, Vidarabine, increasing survival
• rate, but CNS signs, myocarditis may develop

Question 8

Prevention?

Answer 8

Prevention:

• improve keeping conditions of the pups (warm),
• inactivated vaccine
• pregnancy bitch 2x
• (maternal Abs to the pups)