Herpesviridae - Alphaherpesvirinae - Porcine Herpesvirus 1 Flashcards
(26 cards)
What does PHV-1 cause?
Psuedorabies, Aujeszky disease, Mad itch
What species are the hosts of PHV-1?
Pigs
Secondary hosts include horses, cattle, sheep, goats, dogs, cats
Can humans contract PHV-1?
No, they are refractory
What species act as reservoirs?
Pigs
Rodents – transmit from farm to farm
How is PHV-1 transmitted?
Saliva, nasal discharges, and milk of infected pigs through licking, biting, aerosol, ingestion of contaminated carcass, water, and feed.
Can the virus be transmitted in urine or feces
NO
How do dogs and cats get infected with PHV-1?
Ingestion of infected pig meat or bite of infected rodent
How are cattle infected with PHV-1?
Direct contact with infected pigs through the oral and nasal routes
Where is the primary site of viral replication?
Upper respiratory tract
Where else can the virus be located?
CNS via axons of cranial nerves
Preference for neurons of the pons and medulla
What lesions can occur in the CNS due to PHV-1?
Ganglioneuritis
Nonsuppurative meningoencephalitis
Perivascular cuffing
What are the clinical signs of pseudorabies in pigs?
Non-immune piglets: 100% mortality
Non-immune pregnant sows: 50% abortion rate
Older piglets, growers, and adult pigs: <2% mortality rate
What are the clinical signs of pseudorabies in pigs?
Generalized febrile response, anorexia, weight loss
Pruritus is rare in pigs
What is a common clinical sign of pseudorabies in secondary hosts?
Pruritus
What are the clinical signs of pseudorabies in non-immune piglets?
CNS disease
Incoordination of hindlimbs, tremors, paddling
What are the clinical signs of pseudorabies in weaned pigs?
Reduced CNS signs.
Increase in respiratory signs.
Listlessness, depression, sneezing, coughing, moderate fever, vomiting
Incoordination, muscle spasm, circling, convulsions
Headpressing!
What are the clinical signs of pseudorabies in non-immune pregnant sows?
Infection before 30th day – death and resorption of embryo.
Infection in late pregnancy – mummified, stillborn, weak, or normal piglets
Up to 20% of sows aborting are infertile on next breeding
What gross findings would you find in a necropsy?
Often absent or minimal but you may see: Serous to fibrinous rhinitis Necrotic tonsillitis Liver and spleen have yellow-white necrotic foci (2-3mm) Necrotic placentitis and endometritis
What is pseudorabies in cows called?
Mad itch
What are the clinical signs of mad itch?
Intense pruritus causing frenzy– self trauma
Progressive CNS signs, paralysis, ataxia
Death from respiratory failure
Profuse salivation
What are the clinical signs in dogs?
Pruritus with self-mutilation Paralysis of jaws and pharynx Salivation Plaintive howling Dogs do not attack-- unlike rabies
What are the clinical signs in cats?
Often not observed because disease is so rapid
How is PHV-1 diagnosed?
History and clinical signs
Histopathology- intranuclear inclusion bodies
Serology
PCR
When should the PHV-1 vaccine be used?
In enzootic areas to reduce swine losses.
Vaccination does not prevent infection but alleviates clinical signs.
