22. Aujeszky’s disease (aetiology, epidemiology, pathogenesis, clinical signs, post mortem lesions).

Question 1

Occurrence?

Answer 1

• _*NOTIFIABLE*_
• Swine disease with febrile, general signs, abortion, respiratory and CNS signs, which in other susceptible host
• manifests as severe, acute and lethal encephalitis
• History: known for a long time as pseudorabies, mad itch
• Not eradicated in Europe (wild boars spreading - hunting dogs and fox often get infected)
• Suid herpesvirus-1 (SuHV-1), antigenic relationship with BHV-1 (Alphaherpesvirinae)
• Propagating well in cell cultures (nuclear inclusions, syncytium, rounding)
• During passages mutations, deletions - attenuation (gE, gC, gM, gG, TK defected)
• Neutralizing surface antigens: gB, gC, gD
• Risk of recombination, reactivation - use of multiple defected vaccine strains

Question 2

Epizootiology?

Answer 2

Epizootiology:

• Natural host = swine - reservoir
• Mammal and bird species also susceptible: mainly lethal encephalitis,
• naturally birds don’t get sick ofSuHV-1,
• humans are NOT susceptible, in non-swine
• no significant viremia and shedding > noepizootiological impact
• Swine sheds virus in acute phase for 2-3 weeks via nasal discharge
• Convalescent swine is lifelong carrier and shedder
• Reactivation of latent infections after stress
• Semen play a role in spreading
• High virus amount in respiratory tissues - slaughterhouse side-products (in meat less virus, frozen
• storage - inactivated after 40 days)
• Introduction with infected swine, fomites, liquid manure
• Rodents are minor role in transmission
• Within herds contact, airborne, contaminated water and food, mechanical vectors,
• semen and vertical transmission

Question 3

Clinical signs?

Answer 3

Clinical signs:

• incubation 2-8 days, signs and mortality is age-dependent
• Newborn piglet: severe, general, febrile illness, unappetite, vomiting,
• sometimes death within 1-2 days (no CNS signs),
• signs for meningoencephalitis (tremor, restlessness, paralysis, salivation, crying/silence)
• Gilts: febrile illness, unappetite, thrist, sneezing, nasal discharge, polypnea, lung edema, munching,
• trembling nasal and facial muscles, wobbly movements, most recover within 5-6 days, but remaining
• head trembling, nose, eye, ear tic
• Adult pig: often subclinical, constipation, dyspnea, coughing, pregnant sow - infertility, abortion,stillbirth
• Cattle, sheep, goat: 3-6 days incubation time
• Fever, unappetite, agalactia, restlessness, tremor of neck/back muscles, itching, dyspnea,
• pharyngeal paralysis, salivation, meteorism, death within 1-2 days, rare recovery
• Horse: rare, less susceptible, meningoencephalitis
• Carnivores: febrile general signs, itching,
• dog - excitement, stretching, paralysis, death,
• cat -salivation, anisocoria, convulsions, death

Question 4

Pathology?

Answer 4

Pathology:

• Moderate lesions, lung edema
• Suckling piglets: pharyngeal mucosa, tonsils inflammation, necrotic foci (spleen, livertoo)
• Histopath: hemorrhages in LN, visceral organs, nuclear inclusions, interstitial and hemorrhagic
• pneumonia
• Encephalitis: swine - meningitis, cortical lymphocyte cuffing( like we saw in histopathology), glial
• proliferation, regressive processes, spinal cord dorsal horn glia proliferation,
• ruminants/carnivores/rodents - meningitis, brainstem/medulla oblongata glia proliferation