Virology 2 - Food Animals

Question 1

Viruses that cause Congenital malformations

Answer 1

Cattle - BVDV, blue tongue, akabane, schmallenberg
Sheep - border disease, blue tongue, akabane
Pigs - classical swine fever

Question 2

viruses that cause encephalitis

Answer 2

Rabies for ALL
Cattle - BHV 5, malignant catarrhal fever
Sheep & goats - small rum lentivirus
Pigs - classical swine fever, pseudorabies, picornaviruses

Question 3

Border disease

Answer 3

Pestivirus
Disease of newborn sheep from congenital infection of ncp BDV during first half of gestation
Lambs infected early in gestation are persistently infected
Fetal infection after 85 days = normal lambs w antibody

Question 4

Four syndromes of border disease

Answer 4

Early embryonic mortality
Abortion & stillbirth
Congenital malformations
Birth of small, weak lambs w immunosuppression

Question 5

Mechanism for border disease

Answer 5

Tropism for lymphoid tissue, CNS & hair follicles
Development of “hair shaker” lamb due to infection between day 50-63 of gestation
Infection of oligodendrocytes = myelin deficiency

Question 6

Infection of fetus - border disease

Answer 6

Infection during CNS development results in neurologic or ocular degeneration - vasculitis - swelling = necrosis
- cerebellar hypoplasia
- Hydranencephaly (loss of cerebral hemispheres)
- porencephaly (cysts or cavities within cerebral hemispheres)

Question 7

Border disease results in

Answer 7

Hypomyelinogenesis results in tremors
Cerebellar hypoplasia results in ataxia
Hairy birth coat from follicle malformation (fuzzy)
Facial bone malformations
Short-boxy stature
Eye abnormalities

Question 8

Pestivirus in cattle

Answer 8

Infection after 80 days gestation = teratogenic effects
-Vasculitis in cerebellum = swelling, necrosis of external germinal layer, cerebellar hypoplasia
- hypomyelinogeneis
- Hydranencephaly

Question 9

Pestivirus in pigs

Answer 9

Cerebellar hypoplasia
Hypomyelinogenesis (congenital tremors)
Foreign animal disease

Question 10

Malignant catarrhal fever

Answer 10

Ovine herpes virus 2 - sheep
Alcelaphine herpes virus 1 - wildebeest
Caprine herpes virus 2 - goat

Question 11

Species affected by malignant catarrhal fever

Answer 11

Cattle, deer, giraffes, pigs, bison
No clinical disease in natural reservoir hosts
Severe disease can occur in susceptible hosts

Question 12

Pathogenesis of malignant catarrhal fever

Answer 12

Sheep shed during lambing
Clinical signs in susceptible hosts depend on species
Vasculitis - multiple hemorrhage & primary necrosis of epithelium

Question 13

Clinical signs of malignant catarrhal fever

Answer 13

Multiple patechal & mucosal hemorrhage
Corneal edema
Mucopurulent nasal discharge
GIT & bladder hemorrhage
Cutaneous disease
Fatal lyphoproliferative disease

Question 14

Differentiation between rabies, MCF & herpes

Answer 14

Course of neurologic signs
Presence of other clinical signs
Time of year, proximity to other species of animals
Presence of similar disease in other animals
Lab diagnosis

Question 15

Bovine spongiform encephalopathy

Answer 15

Prion protein - infectious proteinaceous particles w/out nuclei acid. Aka abnormal folding of normal glycoprotein
Implicated in fatal neurodegenerative disease w long incubation periods
Non-immunogenicity & extremely resistant to inactivation

Question 16

BSE

Answer 16

No horizontal transmission
Banning ruminant-derived meat & bone meal = decline in cases
Clinical signs include ataxia, hypermetria, falling

Question 17

Caprine arthritis encephalitis

Answer 17

Small ruminant lentivirus
Two major forms
- non suppurative leukoencephalomyelitis (kids, 2-4m)
- non suppurative arthritis- synovitis (adult goats>12m)

Question 18

adult goats & sheep CAE

Answer 18

Adult goats rarely develop chronic interstitial pneumonia or alveolar proteinosis
Sheep lentivirus rarely causes encephalitis, most infections are associated w pneumonia

Question 19

CAE mechanism

Answer 19

Virus replicates in macrophages
Infected goats are infected for life
Seroconversion may take months but will eventually develop antibodies
90% of infected goats are subclinical
Serology can detect infected animals
Transmitted
- vertically through milk
- horizontally via blood

Question 20

Differentiation CAE & rabies

Answer 20

Age of onset of clinical signs
Clinical disease in other animals
Lab diagnosis **

Question 21

Classical swine fever

Answer 21

Pestivirus
Oronasal transmission, virus replicates in tonsil, spreads to regional lymph nodes then blood stream
Virus has affinity for vascular endothelium resulting in vasculitis and petechial hemorrhage
Infection of pregnant sow = stillborn pigs, congenital tremors or normal pigs

Question 22

Gross lesions of classical swine fever

Answer 22

Cerebellar hypoplasia
Petechial hemorrhage, esp in lymph nodes & kidney
Splenic infarcts
Button ulcers in distal ileum near ileocecal valve

Question 23

Atypical porcine Pestivirus

Answer 23

Causes congenital tremors in suckling pigs & pigs up to 14 weeks
Transmission of pathogenesis arent well understood
- higher titers found in respt & oral secretions
- lower titers found in feces
Seroconversion seems high & viremia is low

Question 24

Porcine herpesvirus 1

Answer 24

Aujeskys disease in pigs
Pseuorabies in other speices
PHV01 is the ONLY alphaherpes virus that can infect other species (not zoonotic/not horses)
Eradicated in swine herds but not wild pigs

Question 25

Aujeskys disease

Answer 25

Aerosol transmission (nose to nose)
Virus replicates in epithelium of oropharynx & tonsils
Spreads to regional LN and brain via CN
Becomes latent in trigeminal ganglia (reactivates)
Shed in nasal secretions, milk, semen
Mortality ^ 100% in young pigs

Question 26

Diagnosing Aujeskys disease

Answer 26

By PCR, virus isolation or serology

Question 27

Histopath for Aujeskys disease

Answer 27

Meningitis & perivascular cuffing

Question 28

Differentiation of herpes virus & Pestivirus

Answer 28

Clinical signs
Lab diagnosis