Virology 2 - Food Animals Flashcards
Viruses that cause Congenital malformations
Cattle - BVDV, blue tongue, akabane, schmallenberg
Sheep - border disease, blue tongue, akabane
Pigs - classical swine fever
viruses that cause encephalitis
Rabies for ALL
Cattle - BHV 5, malignant catarrhal fever
Sheep & goats - small rum lentivirus
Pigs - classical swine fever, pseudorabies, picornaviruses
Border disease
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
Four syndromes of border disease
Early embryonic mortality
Abortion & stillbirth
Congenital malformations
Birth of small, weak lambs w immunosuppression
Mechanism for border disease
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
Infection of fetus - border disease
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)
Border disease results in
Hypomyelinogenesis results in tremors
Cerebellar hypoplasia results in ataxia
Hairy birth coat from follicle malformation (fuzzy)
Facial bone malformations
Short-boxy stature
Eye abnormalities
Pestivirus in cattle
Infection after 80 days gestation = teratogenic effects
-Vasculitis in cerebellum = swelling, necrosis of external germinal layer, cerebellar hypoplasia
- hypomyelinogeneis
- Hydranencephaly
Pestivirus in pigs
Cerebellar hypoplasia
Hypomyelinogenesis (congenital tremors)
Foreign animal disease
Malignant catarrhal fever
Ovine herpes virus 2 - sheep
Alcelaphine herpes virus 1 - wildebeest
Caprine herpes virus 2 - goat
Species affected by malignant catarrhal fever
Cattle, deer, giraffes, pigs, bison
No clinical disease in natural reservoir hosts
Severe disease can occur in susceptible hosts
Pathogenesis of malignant catarrhal fever
Sheep shed during lambing
Clinical signs in susceptible hosts depend on species
Vasculitis - multiple hemorrhage & primary necrosis of epithelium
Clinical signs of malignant catarrhal fever
Multiple patechal & mucosal hemorrhage
Corneal edema
Mucopurulent nasal discharge
GIT & bladder hemorrhage
Cutaneous disease
Fatal lyphoproliferative disease
Differentiation between rabies, MCF & herpes
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
Bovine spongiform encephalopathy
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
BSE
No horizontal transmission
Banning ruminant-derived meat & bone meal = decline in cases
Clinical signs include ataxia, hypermetria, falling
Caprine arthritis encephalitis
Small ruminant lentivirus
Two major forms
- non suppurative leukoencephalomyelitis (kids, 2-4m)
- non suppurative arthritis- synovitis (adult goats>12m)
adult goats & sheep CAE
Adult goats rarely develop chronic interstitial pneumonia or alveolar proteinosis
Sheep lentivirus rarely causes encephalitis, most infections are associated w pneumonia
CAE mechanism
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
Differentiation CAE & rabies
Age of onset of clinical signs
Clinical disease in other animals
Lab diagnosis **
Classical swine fever
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
Gross lesions of classical swine fever
Cerebellar hypoplasia
Petechial hemorrhage, esp in lymph nodes & kidney
Splenic infarcts
Button ulcers in distal ileum near ileocecal valve
Atypical porcine Pestivirus
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
Porcine herpesvirus 1
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
Aujeskys disease
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
Diagnosing Aujeskys disease
By PCR, virus isolation or serology
Histopath for Aujeskys disease
Meningitis & perivascular cuffing
Differentiation of herpes virus & Pestivirus
Clinical signs
Lab diagnosis
