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187 Cards in this Set
- Front
- Back
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Definition of a virus:
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• Obligatory intracellular parasite with
genetic material enclosed in a protein shell |
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Individual virus particle
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• Virion:
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Protein coat surrounding the
nucleid acid |
• Capsid:
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Protein subunits that
make up the capsid |
• Capsomer:
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Lipoprotein coating
surrounding the capsid derived from infected cell membrane |
• Envelope:
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Icosahedral symmetry
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•12 vertices
•20 faces •30 edges |
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Viral Proteins
• Structural: |
Viral Proteins
• Structural: Part of the virus particle • Virus architecture • Protective coat • Viral receptors • Antibody response |
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Viral Proteins
• Non-structural: |
Seen only in infected
cells • Viral replication/enzymatic function • Regulation |
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Viral lipids
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• 20-55% of dry weight of enveloped
viruses • 50-60% phospholipid, remaining cholesterol • Ether-chloroform sensitive |
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viral Carbohydrates:
Serve as components of: |
• Viral glycoprotein “gp”
• Viral antigens • Receptors |
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Virus Family:Aslarviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Aslarviridae
>size:large >+/- envelope:+ >symmetry:icosohedral >RNA or DNA:DNA |
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Virus Family:Poxviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Poxviridae
>size:large >+/- envelope:+/- >symmetry:complex >RNA or DNA:DNA |
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Virus Family:Iridoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Iridoviridae
>size:large >+/- envelope:+ >symmetry:Icosohedral >RNA or DNA:DNA |
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Virus Family:Herpesviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Herpesviridae
>size:Medium >+/- envelope:+ >symmetry:icosohedral >RNA or DNA:DNA |
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Virus Family:Adenoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Adenoviridae
>size:Medium >+/- envelope:- >symmetry:icosohedral >RNA or DNA:DNA |
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Virus Family:Papoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Papoviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:DNA |
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Virus Family:Parvoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Parvoviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:DNA |
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Virus Family:Circoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Circoviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:DNA |
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Virus Family:Hepadnaviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Hepadnaviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:DNA |
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Virus Family:Retroviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Retroviridae
>size:Medium >+/- envelope:+ >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Reoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Reoviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Birnaviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Birnaviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Paramyxoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Paramyxoviridae
>size:large >+/- envelope:+ >symmetry:Helical >RNA or DNA:RNA |
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Virus Family:Rhabdoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Rhabdoviridae
>size:medium >+/- envelope:+ >symmetry:Helical >RNA or DNA:RNA |
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Virus Family:Filoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Filoviridae
>size:large >+/- envelope:+ >symmetry:Helical >RNA or DNA:RNA |
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Virus Family:Bornoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Bornovirdae
>size:small >+/- envelope:+ >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Orthomyxoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Orthomyxoviridae
>size:Medium >+/- envelope:+ >symmetry:Helical >RNA or DNA:RNA |
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Virus Family:Bunyaviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Bunyaviridae
>size:Medium >+/- envelope:+ >symmetry:Helical >RNA or DNA:RNA |
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Virus Family:Arenoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Arenoviridae
>size:large >+/- envelope:+ >symmetry:Helical >RNA or DNA:RNA |
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Virus Family:Coronaviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Coronaviridae
>size:large >+/- envelope:+ >symmetry:Helical >RNA or DNA:RNA |
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Virus Family:Arteriviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Arteriviridae
>size:small >+/- envelope:+ >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Picornaviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Picornaviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Caliciviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Caliciviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Astroviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Astroviridae
>size:small >+/- envelope:- >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Togoviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Togoviridae
>size:small >+/- envelope:+ >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Flaviviridae
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Flaviviridae
>size:small >+/- envelope:+ >symmetry:icosohedral >RNA or DNA:RNA |
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Virus Family:Deltavirus
>size: >+/- envelope: >symmetry: >RNA or DNA: |
Virus Family:Deltavirus
>size:small >+/- envelope:+ >symmetry:? >RNA or DNA:RNA |
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Ten steps of viral replication
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1.Attachment
2.Penetration 3.Uncoating 4.Transcription of early mRNA 5.Translation of early proteins 6.Replication of viral DNA 7.Transcription of late mRNA 8.Translation of late proteins 9.Assembly of virions 10.Release |
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In general DNA viruses replicate in the _________ and RNA viruses replicate in the _____________
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In general DNA viruses replicate in the _Nucleus_ and RNA viruses replicate in the _Cytoplasm_
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DNA viruses families that replicate in the cytoplasm
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Poxviridae
Asfarviridae |
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RNA viruses families that replicate in the nucleus
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Retroviridae
Bornoviridae Othomyxoviridae |
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Family:Poxviridae
Virus:Vaccinia virus Receptor on target cell: |
Family:Poxviridae
Virus:Vaccinia virus Receptor on target cell:Epidermal growth factor receptor 1 |
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Family:Retroviridae
Virus:HIV Receptor on target cell: |
Family:Retroviridae
Virus:HIV Receptor on target cell:CD4 and more than 10 coreceptors |
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Family:Rhabdoviridae
Virus:Rabies virus Receptor on target cell: |
Family:Rhabdoviridae
Virus:Rabies virus Receptor on target cell:Acetylcholine receptor, gangliosides, phospholipids |
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Family:Orthomyxoviridae
Virus:Influenza A Receptor on target cell: |
Family:Orthomyxoviridae
Virus:Influenza A Receptor on target cell:Sialic acid containing oligosaccharides |
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Family:Picornaviridae
Virus:Rhinoviruses receptor on target cell: |
Family:Picornaviridae
Virus:Rhinoviruses receptor on target cell:ICAM-1 |
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Types of virus infection of cells:
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1.Transforming/oncogentic:infected cells become transformed or oncogenic due to viral effects. Whole viral genome may not be present
2.Acute/lytic: infected cell killed rapidly 3.Latent/proviral:Whole viral genome maitained as free or intergrated DNA with very limited expression 4.Persistent/chronic/slow: most cells are not killed not all cells are infected |
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Types of cells for virus infection:
• Permissive cells: • Non-permissive cells: |
Types of cells for virus infection:
• Permissive cells: Complete virus replication resulting in virus production (e.g. BVD virus in bovine cells) • Non-permissive cells: No virus growth, and no virus production (e.g. BVD virus in canine cells) |
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Cytopathic effects (CPE) of
viruses: morphological changes |
• Cell rounding (e.g. VSV)
• Cell fusion and syncytia (e.g.Herpes virus) • Inclusion bodies (e.g. Rabies virus, Negri bodies) • Vacuoles (e.g. BVDV) |
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Non-cytocidal viruses:
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• No CPE produced (e.g. some
retroviruses, non-CPE BVD) • Viral persistence • Long range effects • Antigenic changes |
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Effects of noncytocidal viruses
on function of specialized cells |
• Lymphocytic choriomeningitis virus
(LCM) • lowers acetyl choline production in neuroblastoma cells • lowers insulin production in Beta cells • Rhinovirus infection of respiratory epithelium, leads to cilial stasis |
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viral caused Cell transformation
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• Loss of contact inhibition
• Aneuploidy (abnormal chromosome numbers) |
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pox virus inclusion bodies
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cytoplasm
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Herpes virus inclusion bodies
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nulceus fragments
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Reovirus inclusion bodies
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cytoplasm inclusions that hug nucleus
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Adeno virus inclusion bodies
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nucleus fragments
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Rabies virus inclusion bodies
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cytoplasmic inclusions in neurons
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K9 distemper inclusion bodies
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cytoplasm and nucleus
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Steps of viral pathogenesis
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1.Infection
2.move from lymph and blood to target organs (primary viremia) 3.replication in target oragan 4.movement to blood (secondary viremia) 5.shedding and repication in other organs (shedding dose not occur in brain) |
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Influenza viruses belong to this family
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Orthomyxoviridae
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Influenza Viruses
Important Concepts: |
Influenza Viruses
Important Concepts: • Segmented genome • Antigenic variation • Role of viral protein (HA) in pathogenesis • Some are zoonotic |
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Orthomyxoviruses Classification and properties:
• Four Genera: |
• Four Genera:
• Type A: Animal and human • Type B: Primarily human • Type C: Primarily human • Thogotovirus:animal and human |
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Properties of influenza virus
• Pleomorphic, enveloped • ___________-sense RNA genome, __ segments • ___________ replication, budding from _________ ____________ • Hemagglutinin (HA) and Neuraminidase (NA) on surface |
• Pleomorphic, enveloped
• Negative-sense RNA genome, 8 segments • Nuclear replication, budding from cell surface • Hemagglutinin (HA) and Neuraminidase (NA) on surface |
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Examples of human and animal
influenza viruses |
Human: H1N1,H2N2,H3N2 Swine:H1N1,H3N2
Horse:H7N7,H3N8 |
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Antigenic variation: changes in
HA molecule • Antigenic drift: |
minor changes
• Slow evolution • Point mutations • Immunological pressure • Changes in more than 2 epitopes |
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Antigenic variation: changes in
HA molecule • Antigenic shift: |
major Ag change
• Abrupt change • Mostly originate in China |
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Molecular basis of virulence and
pathogenicity of influenza virus |
• Cleavability of HA by host protease
• Local infection vs. pantropic infection • Gene constellation |
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Equine influenza H and N types:
type of infection: |
H7N7: equine 1
H3N8: equine 2 Not much antigen change Respiratory, aerosol infection |
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Equine influenza:
icubation period: recovery: |
• I.P. 1-3 days
• upper respiratory tract symptoms, fever • secondary bacterial infection • recovery 1-2 weeks |
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Equine influenza vaccination
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Vaccines - bivalent inactivated
vaccine 3 doses, 8-12 weeks apart Race horses - every 3-6 months |
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Hong Kong Bird Flu
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H5N1
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Avian influenza:
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• Generalized infection
• Virulent subtypes - H5, H7 • Hong Kong Bird Flu - H5N1 • Respiratory signs • Edema • Diarrhea • Pantropic spread, high mortality • Control: quarantine, restrict trade, control wild birds |
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Diagnosis of influenza
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• Virus isolation
• Serology |
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Properties of Paramyxoviruses
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• 4 genera
• Pleomorphic, enveloped • Negative-sense RNA genome • Helical symmetry of nucleocapsid • Hemagglutinin and Fusion proteins • Cytoplasmic relication • Syncytium formation • Intracytoplasmic and intranuclear inclusion bodies |
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Paramyxoviruses Important Diseases:
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• Respirovirus genus: Bovine
parainfluenza virus 3 • Rubulavirus genus: Newcastle disease virus of Avians • Morbillivirus genus: Canine distemper virus, Rinderpest virus • Pneumovirus genus: Bovine respiratory syncytial virus |
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• Morbillivirus genus: Canine distemper host range and transmission
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• Canidae - dog, fox, coyote, etc
• Procyonidae - raccoon, panda, etc. • Mustelidae - mink, skunk, otter, etc. • Transmission: • All secretions, excretions • Direct contact, droplet infection |
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Canine distemper susceptibility
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• Young - more susceptible
• 4-6 months ( maternal Ab • Urban dogs - more frequent • Rural - less frequent but more catastrophic |
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Canine distemper symptoms and lesions
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• Biphasic febrile response
• Anorexia, conjunctivitis, nasal discharge • Respiratory: bronchitis, tonsillitis, cough, bronchopneumonia • GIT: vomiting, diarrhea |
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Canine distemper pathogenesis
Acute Phase 1 Day After Infection Virus In __________ ____________ 2 Day After Infection Virus In _________ ______________ 3 Day After Infection Virus In ________ ____________ _______ 4-6 Days After Infection Virus In _____, _______, ______ _____, ____ ____ 7 Days After Infection Virus In ________ ________ cells below epithelium of visceral organs and skin and perivascular spaces in central nervous system ___to ___ Days After Infection Virus In Surface epithelium, glandular epithelium, and cells of central central nervous system ___ to ___ Days After Infection: Recovery (complete antibody formation) or Continued viral replication (restricted antibody formation) __ Days After Infection: Acute encephalomyelitis (fatal) |
Acute Phase
1 Day After Infection Virus In Alveolar macrophages 2 Day After Infection Virus In Bronchial lymph nodes 3 Day After Infection Virus In Blood mononuclear cells 4-6 Days After Infection Virus In Thymus, spleen, bone marrow, lymph nodes 7 Days After Infection Virus In Migrating mononuclear cells below epithelium of visceral organs and skin and perivascular spaces in central nervous system 8-10 Days After Infection Virus In Surface epithelium, glandular epithelium, and cells of central central nervous system 10-30 Days After Infection: Recovery (complete antibody formation) or Continued viral replication (restricted antibody formation) 20 Days After Infection: Acute encephalomyelitis (fatal) |
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Canine distemper late complications
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1-2 months post infection: late demyelinating encephalomyelitis
24 months and onwards following continued replication in neurons, gradual onset of old dog encephalitis (very rare very fatal) Hard pad disease- hyperkeratosis of foot pad |
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Canine distemper neurological symptoms
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seizures
ataxia paresis |
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Canine distemper mortality:
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30-80% surviving dogs have CNS sequelae
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Canine distemper diagnosis
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• Viral infected cells by IF
• Histopathology: • Inclusions bodies - brain, lung, stomach, bladder, etc. |
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canine distemper immunity
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• Recovery with life long immunity
• Vaccination - live virus vaccine - 8, 12, 16 weeks |
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Parainfluenza - 3 (PI - 3)
• Wide-spread in ________ • Most have _________ - subclinical infections • _______ - predisposes to shipping fever SIGNS: • ___________ necrosis, syncytia • Decreased __________ activity • __________ pneumonia results in some cases |
• Wide-spread in cattle
• Most have antibodies - subclinical infections • Stress - predisposes to shipping fever • Epithelial necrosis, syncytia • Decreased ciliary activity • Interstitial pneumonia results in some cases |
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Bovine Respiratory syncytial Virus
(BRSV) • Mostly mild, ____________ disease • Acute _____ respiratory infections in some cases CPE: • _____________, ________________ ____________ • Young and recently weaned calve _______________ pneumonia – bronchopneumonia • ________ - predisposes to shipping fever |
• Mostly mild, subclinical disease
• Acute lower respiratory infections in some cases • Syncytia, intra-cytoplasmic inclusions • Young and recently weaned calves Interstitial pneumonia – bronchopneumonia • Stress - predisposes to shipping fever |
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Viral - bacterial synergism in
disease • Shipping Fever: multi-factorial etiology • Stress factors: |
• Transport
• Exhaustion, starvation • Dehydration, chilling, overheating • Dusty conditions • Over-crowding • Nutritional changes |
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Shipping fever
viruses: bacteria: |
•Viruses
• PI3 • IBR • BVD • BRSV • Bacteria • Pasteurella - Bronchopneumonia |
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Togaviridae General Properties
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• Two genera, Alphavirus and Rubivirus
• Only Alphavirus is insect-borne • Enveloped, spherical • Positive-sense RNA genome • Cytoplasmic replication • Budding from plasma membrane |
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Togaviridae important diseases/viruses
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• Eastern equine encephalitis virus
• Western equine encephalitis virus • Venezuelan equine encephalitis virus |
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Arboviruses general
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• 500 arboviruses known
• 16 cause disease in animals • Transmission of arboviruses: • Mechanical transmission - "Flying pins" (e.g. Swine pox, E1A) • Biological transmission - (e.g. EEE) |
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Recent increased arboviral
activity due to: |
• Geographic intrusion, deforestation
• Irrigation, urbanization • Increases in long distance travel • New routing of bird migration |
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Equine encephalitis pathogeneis:
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• Bite of arthropod vector
• Replication at site of entry • Spread through lymphatics • Viremia (primary) • Secondary viremia • Entry into CNS • Encephalitis (neuronal necrosis, inflammation) • Replication in RE cells and striated muscle, etc. |
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• Eastern equine encephalitis virus
• Western equine encephalitis virus • Venezuelan equine encephalitis virus control and diagnosis |
Diagnosis
• Virus isolation • Serology Control • Vaccination |
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Flaviviruses
• Important concepts: |
Arboviruses and non-arboviruses
• Some are zoonotic • Transplacental infections and consequences • Teratological effects • Interactions between cytopathic and noncytopathic viruses in causing disease |
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Flaviviruses General properties
• Enveloped, spherical • Surface _______________ • ______-sense RNA genome, • __________ replication • ____________ translation followed by cleavage • _____________ budding |
• Enveloped, spherical
• Surface glycoproteins • Positive-sense RNA genome, • Cytoplasmic replication • Polyprotein translation followed by cleavage • Intracytoplasmic budding |
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Flaviviruses important virues
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• Genus Flavivirus, mostly insect-borne.
• Yellow fever virus • Japanese encephalitis virus • West Nile virus • Genus Pestivirus, non insect-borne. • BVDV • Hog cholera virus • Border disease virus |
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BVDV has only a single ______ but multiple _______ occur
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BVDV has only a single _serotype_ but multiple _strains_ occur
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Two biotypes of BVDV
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Two biotypes based
on CPE • Cytopathic (CP) • Non-cytopathic (NCP) • NCP can convert into CP virus |
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Genotypes of BVDV
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Genotypes: by genetic analysis
• Classical BVDV • Hog cholera virus or CSFV • "True" border disease virus • BVDV type II and some BDV |
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BVDV Clinical picture and pathology:
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mostly subclinical
• In acute cases: Diarrhea – Erosive lesions in GIT – Sometimes death • Fetal infections • Congenital problems • Viral persistence |
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BVDV Three scenarios of infection and
consequences |
• Infection of adult cattle - mild to severe
• Infection of pregnant cattle - fetal infection mild to severe • Superinfection of persistently infected cattle |
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Events leading to mucosal disease
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Infection of a pregnant cow with noncytopathic BVDV
during early gestation results in in-utero infection of the developing fetus Cow recovers from infection by making antibody. Fetus survives infection, becomes immunotolerant to the virus and no antibody is produced Apparently normal calf is born with persistent viral infection Calf reaches adulthood, becoming a lifelong carrier. Superinfection with a cytopathic BVDV of either endogenous origin (mutation of resident noncytopathic virus) or exogenous source can occur Due to immunotolerance, animal is unable to mount an effective immune response to control the cytopathic virus and succumbs to muscosal disease |
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Mucosal disease (MD) –2 steps
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Mucosal disease (MD) –
always deadly • Step 1 - NCP virus in utero infection - Immunological tolerance • Step 2 - Superinfection with CP virus - cell destruction, no immune response - death (MD) |
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BVDV diagnosis and control
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• Virus Isolation and serology
• Vaccination • Test and get rid of persistently infected cattle • Persistently infected cattle are antibody negative, virus positive |
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_________ virus is a common cell culture contaminant
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BVDV
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In BVDV persistently infected calves are __________
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poor doers
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Retroviruses
Important Concepts: |
• Reverse transcriptase
• Chromosomal integration of viral genome • Antigenic variation • Viral persistence • Oncogenesis |
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Retroviruses properties
• Enveloped, spherical • ss ______ ______-sense RNA genome • Some have ________, defective • ___________ _________ enzyme, DNA intermediate • Genome integration into host cell DNA(________) • Budding from ________ ________ |
• Enveloped, spherical
• ss diploid positive-sense RNA genome • Some have oncogene, defective • Reverse trancriptase enzyme, DNA intermediate • Genome integration into host cell DNA(provirus) • Budding from plasma membrane |
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Retroviruses Important Disease/viruses
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Important Diseases/Viruses
• Genus Alpharetrovirus: Avian leucosis virus and Rous sarcoma virus • Genus Betaretrovirus:Jaagsiekte virus-sheep and Simian type D virus • Genus Gammaretrovirus: Feline leukemiavirus and Feline sarcoma virus • Genus Deltaretrovirus: Bovine leukemia virus and HTLV I and II • Genus Lentivirus:Feline immunodeficiency virus, Human immunodeficiency virus, Equine infectious anemia virus, and Caprine arthritis encephalitis virus • Genera Epsilonretrovirus and Spumavirus |
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Type C Retroviruses
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• Endogenous - No pathology
• Exogenous replication competent - FeLV • Exogenous defective - FeS |
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Feline Leukemia Virus (FeLV)
• Woldwide • Most common ___________ death (250 / 100,000 die annually) • Prevalence: __% isolated populations • 50% urban & colony cats • ________ contains virus at 106/ ml • Normally, prolonged direct exposure required TRANSMISSION: • ________, _______ _______ • _________ • ___________ infections |
• Woldwide
• Most common non-accidental death (250 / 100,000 die annually) • Prevalence: 6% isolated populations • 50% urban & colony cats • Saliva contains virus at 106/ ml • Normally, prolonged direct exposure required • Fleas, mutual grooming • Biting during fighting • Iatrogenic infections |
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FeLV Disease Progression and
Pathogenesis |
• Majority of cats - effective immune
response - recovery • Some cats - ineffective immune response - virus persistence - disease |
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Predominant form of neoplasm in FeLV
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- Lymphosarcoma
• Symptoms depend on location of lesion: • Alimentary - vomiting, diarrhea • Thymic - coughing, dysphagia, dyspnea • Multicentric - many organs • Lethargic, anorexia, weight loss |
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FeLV Effect on hematopoietic system
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• Lymphoblastic leukemia
• Erythroleukemia • Myelogenous leukemia • Anemia |
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Immunocomplex disease caused by FeLV
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• Glomerulonephritis
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Common results from Immunosuppression in FeLV
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• Secondary infections
• Repeated infections • Chronic stomatitis • Gingivitis • FIP, etc... |
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FeLV Diagnosis and control
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Diagnosis
• IFA • ELISA Control • Killed virus vaccine |
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Feline sarcoma virus
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causes Fibrosarcoma
• 6% - 12% of all feline tumors • old cats - solitary tumors • young cats - multifocal s/c tumors • Defective virus with oncogene, transmitted with FeLV |
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FIV genral
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Lentivirus - 1986
• World wide, also in wild cats • Bite transmission • Clinical signs (1-2 months) – depression, fever, lymphadenopathy – Signs disappear in a few weeks • Virus persists: months to years • Immunosuppresion • CD4 Cell loss • stomatitis, gingivitis, enteritis • neurological dysfunction |
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FIV diagnosis and control
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Diagnosis
• ELISA Control • vaccines |
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Bovine Leukemia Virus (BLV)
• mostly _______________ • __% persistent lymphocytosis • multistage process |
• mostly asymptomatic
• 30% persistent lymphocytosis • multistage process |
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Caprine Arthritis Encephalitis
(CAE) • Goats • Progressive encephalomyelitis ___ months • Arthritis >_____ months • ____ and _____ (infectious) zooinotic? |
• Goats
• Progressive encephalomyelitis 2-4 months • Arthritis >12 months • Milk, colostrum (infectious) |
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Equine Infectious Anemia (EIA)
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• Horses
• Insect transmission • Antigenic variation • Immune complex disease |
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Properties of Picornaviruses
• Small, non-enveloped • Ss ______-sense RNA genome • ____________ replication • Polyprotein translation and cleavage • RNA is ________________ • Subgenomic RNAs seen in Calicivirus |
• Small, non-enveloped
• Ss positive-sense RNA genome • Cytoplasmic replication • Polyprotein translation and cleavage • RNA is infectious • Subgenomic RNAs seen in Calicivirus |
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Picornaviruses Important Diseases/Viruses
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• Apthovirus genus: Foot and mouth
disease virus • Enterovirus genus: Swine vesicular disease virus • Many other genera: Eg. Rhinovirus |
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viruses that cuase Vesicular Diseases
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• Identical lesions, but can be caused by
different viruses • Foot and mouth disease (FMDV) Picornavirus • Vesicular stomatitis (VSV) Rhabdovirus • Swine vesicular disease (SVDV) Picornavirus • Vesicular exanthema (VEV) Calicivirus |
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vesicular diseases hosts and susceptiblity
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Foot and mouth:S-cattle,sheep,swine;R-horse
swine vesicular disease:S-swine;R-cattle,sheep,horse vesicular stomatitis:S-cattle,sheep,swine,horse Vesicular exanthema of swine:S-swine;R-cattle,sheep,horses |
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Foot and mouth disease
______ serotypes, many subtypes |
Foot and mouth disease
7 serotypes, many subtypes • South America - O, A, C • Europe - O, A, C • Africa - O, A, C SAT 1, 2, 3 • Asia - O, A, C Asia-1 • Some countries - disease free • USA - 1929 • Canada - 1951 • Mexico - 1954 |
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foot and mouth all _________ animals are susceptible
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All cloven hooved animals susceptible
• Cattle • Swine • Sheep • Goat • Buffalo • Wildlife - 70 species of 20 families |
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Foot and mouth General characteristics
• Morbidity - ____ • Mortality - ____ • ___________ convalescence • Virus shedding • Explosive spread in _________ – epidemics • Loss of ______ __________ • Retarded _____ _________ |
• Virus very stable
• Morbidity - high • Mortality - low • Protracted convalescence • Virus shedding • Explosive spread in "virgin soil" – epidemics • Loss of milk production • Retarded weight gain |
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Foot and mouth viral entry
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• Inhalation of droplets
• Ingestion • Contact • Infected semen |
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foot and mouth pathogenesis
• IP ______ days • Initial replication in _________ • Viremia, spread to other organs • Fever • Salivation • Vesicles in ______, ______, ______, ______, _________ ________, ________ ______, • Lameness, secondary bacterial infections • Young animals - _________ • Pregnant animals - __________ |
• IP 2 to 8 days
• Initial replication in pharynx • Viremia, spread to other organs • Fever • Salivation • Vesicles in mouth, tongue, gums, teats, interdigital skin, coronary band, • Lameness, secondary bacterial infections • Young animals - myocarditis • Pregnant animals - abortion |
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foot and mouth viral excretion and carrier state
• Viral excretion ___________ symptoms • Large amount of virus in _______ and _______ • Viral persistence in _______ - ~2 years (cattle) • _(animal)_, no persistence • Carrier state: ______________ |
• Viral excretion 24 hours before symptoms
• Large amount of virus in vesicles and milk • Viral persistence in pharynx - ~2 years (cattle) • Swine, no persistence • Carrier state: African cape buffalo |
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Foot and mouth in swine sheep and goats
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• Swine: Foot lesions more serious
– Vesicles on snout • Sheep and Goats: milder disease, lameness |
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Foot and mouth immunity
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• IgM, broad protection
• IgG, type specific • ~1 year, not life long |
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Foot and mouth diagnosis
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• Virus isolation and typing
• ELISA • Virus neutralization |
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Foot and mouth epidemiological considerations
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• Rapid spread - quarantine measures
• Severity - endemic vs. virgin soil epidemics • Airborne spread - materiological modeling |
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Vesicular stomatitis virus (VSV) serotypes and hosts
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Vesicular Stomatitis Virus (VSV)
Two serotypes: • VSV - Indiana • VSV - New Jersey Broad host range virus: • Cattle, Horses, Pigs |
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Vesicular stomatitis virus occurrence in the USA
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Periodic occurrence in the USA
• Reoccurs about every 10-12 years – USA - 1982-83 - VSV-NJ – 1995 - VSV-NJ – 1997 - both VSV-NJ and VSV-Indiana |
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Where is vesicular stomatitis virus endemic
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mexico and central america
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Transmission of vesicular stomatitis virus
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Transmission
• Contact • Insects, milking machines • Sandflies |
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Vesicular stomatitis virus
lesions:___ ____ ___ ___ ___ symptoms:_______ ________ IP:_________ |
Symptoms, lesions
• IP - 1 to 5 days • Fever • Salivation • Vesicular lesions - tongue, mouth, teats, coronary band, hoof |
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Vesicular stomatitis virus immunity
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Immunity
• Not life long • Strain specific • IgA Important |
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Swine Vesicular Disease Virus: SVDV
- ____________ genus of (_family_) • Virus highly resistant to ___ __, ______ temperature • Symptoms, lesions similar to FMD • __ persistent infection • Sudden appearance of lameness in herd |
- Enterovirus genus of Picornaviridae
• Virus highly resistant to low pH, ambient temperature • Symptoms, lesions similar to FMD • No persistent infection • Sudden appearance of lameness in herd |
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Vesicular Exanthema (swine) -
Calicivirus |
• First seen in southern California
• 1952 – Nebraska, spread to 42 states (in a few months) • Sporadic outbreaks • Lesions similar to FMD • 13 antigenic types • Morbidity high, Mortality low • Garbage cooking laws • Slaughter - control (1956) |
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San Miguel Sea Lion Virus
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• 1972 - California
• Seals, sea lions - vesicular lesions of flippers • Pacific walrus, bottle nosed dolphin • Antigenic variants generated in sea animals |
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Rhabdoviruses (rabies)properties
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• Enveloped, bullet shaped
• Ss negative-sense RNA genome • Cytoplasmic replication • Budding through plasma membrane |
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Rhabdoviruses important diseases/viruses
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• Genus Lyssavirus: Rabies virus
• Genus Vesiculovirus: Vesicular stomatitis |
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Rabies genral
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• Infects all warm blooded animals
• Most instances death • 40-50,000 human deaths worldwide each year • 10 million people annually receive postexposure treatment worldwide • In Central and South America 1 million cattle/year • Some island countries - no rabies (eg. Australia, Japan) • Wildlife populations - rabies is a problem |
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Rabies transmission
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• Bites, infected saliva
• Scratches, open wounds • Vampire bats • Bat caves - inhalation • Feeding on infected animals |
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Rabies pathogenesis general
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• Neurotropic virus
• Incubation period – 14-90 days, sometimes longer – Site and severity of bite affects IP |
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clinical forms of rabies
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1) Furious form
• Restlessness • Aggressive, excitement • Biting • Excessive salivation • Hypersensitive to light, sound • Progression to paralysis • "Hydrophobia" 2) Dumb, paralytic form • Incoordination • Paralysis • Loss of condition |
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Rabies first phase of infection
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First phase of infection
• Virus multiplies at site of bite, muscle cells, subepithelial tissue • Virus levels increase locally • Motor or sensory nerve endings • Binds to acetyl choline receptor |
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Rabies second phase of infection
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Second phase of infection
• Centripetal movement • Travels through cytoplasm of axons, CNS • Extensive replication • Release of cortical control of behavior - furious form • Replication in neocortex - dumb form • Death 2-7 days after symptoms, from respiratory arrest |
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Rabies spread to salivary glands
• Virus movement from CNS centrifugally through nerves to other organs - _________ ________, _______ ________, _________ • ______ ________, high concentration of virus in saliva • Very little antigen is released • Very little host ________ response, no CPE • Negri bodies" - cytoplasmic inclusions in brain • Viral "G" protein responsible for pathology? |
• Virus movement from CNS centrifugally
through nerves to other organs - salivary glands, adrenal cortex, pancreas • Apical budding, high concentration of virus in saliva • Very little antigen is released • Very little host inflammatory response, no CPE • Negri bodies" - cytoplasmic inclusions in brain • Viral "G" protein responsible for pathology? |
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Rabies diagnosis
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Diagnosis
• FA test, brain tissue • Inclusion bodies • PCR |
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Rabies treatment and ptophylaxis
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• Inactivated virus vaccine
• Attenuated virus vaccine • Pre-exposure immunization • recommended for all high risk groups • Post exposure vaccination • Rationale and mechanism |
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Poxviridae virus properties
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• Mostly brick shaped with complex
symmetry • Large in size • Large ds genomic DNA • Cytoplasmic replication • Release by exocytosis and cell lysis • Viral Vector |
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poxvirus important diseases/viruses
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• Cowpox virus
• Vaccinia virus • Sheeppox virus • Swinepox virus • Orf virus • Pseudocowpox virus |
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Poxvirus infections
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• Localized and surface infections
• Some also cause systemic disease • Dermatotropism is a general feature |
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Transmission of pox viruses
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• Contact
• Skin abrasions • Droplet infections - sheep pox • Insect transmission (mechanical): swine pox, fowl pox |
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Cowpox
• ______ and ______ lesions, pustular lesions • IP - _____ • Local ______ ________, pustule rupture, ulceration • Several weeks to heal • _(ocupation)_ infected • Contaminated _______ _______ can transmit • _______ - reservoir of virus in nature • Serious generalized infections in some zoo animals (e.g. elephants, large cats) • Zoonotic? |
• Teat and udder lesions, pustular
lesions • IP - 5 days • Local erythemia vesicle, pustule rupture, ulceration • Several weeks to heal • Milkers infected • Contaminated milking machines can transmit • Rodents - reservoir of virus in nature • Serious generalized infections in some zoo animals (e.g. elephants, large cats) • Zoonotic |
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Orf virus
Orf (__________ __________ _____________) • Effects ______ and _____ mostly • Lesions on _______ and _____ • Morbidity ______ • Zoonotic? |
Orf (contagious pustular
dermatitis) • Sheep and goats • Lesions on muzzle and lips • Morbidity high • Zoonotic |
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Pseudocowpox
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• Nodular, proliferative lesions
• Papule - dark red scab with extended edges • Center umbilicated - desquammation - ring or "horse shoe" scab |
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Swinepox
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• Lesions on the belly
• 1-2 cm in diameter • Pig louse transmission |
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pox virus systemic diseases
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• Sheeppox and lumpy skin disease
viruses • Problematic in other regions of the world • Skin and visceral lesions • Cell associated viremia |
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Papilloma virus properties
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• Non-enveloped, spherical
• Circular ds DNA genome • Nuclear replication • Episomal DNA, may be oncogenic • Virus maturation in differentiated cells |
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Papilloma virus important diseases/viruses
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• Bovine papilloma
• Equine papilloma Canine papilloma |
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Bovine papillomatosis (warts) types and antigenic groups
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6 types
2 antigenic groups 1,2,5 3,4,6 |
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Bovine papillomatosis general
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• Viral DNA remains episomal
• DNA replication basal squamous epithelial cell • Viral maturation in terminally differentiated keratinized cells |
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Bovine papillomatosis sysmptoms and lesions
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• Young animals - higher incidence
• Viral entry through skin abrasions • Head, neck, shoulders, udder, genitalia • IP - 4 to 6 weeks |
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papilloma leison
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• Fibrous core
• Large warts, abrasion, bleeding • ~ 4 - 6 months - spontaneous regression |
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Bovine Papilloma
Virus 4 (BPV 4) |
• Scotland and England
• Alimentary tract, urinary bladder papillomas • Can progress to squamous cell carcinomas • Bracken fern - co-carcinogen and immunosuppresant |
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Papilloma Control and treatment
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• Surgical removal
• Cryotherapy • Autologous vaccines |
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Impact of vaccination in the
control of viral diseases |
• FMD, hog cholera eradicated
• Incidence of many diseases decreased |
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Basis for immunity with viral
vaccines |
• Humoral immunity: neutralizing antibody
• Cell mediated immunity: cytotoxic T cells |
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Varieties of viral vaccines
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• Live virus vaccines
• Non-replicating native antigen vaccines • Recombinant DNA / Innovative Vaccines |
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Types of live virus vaccines
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• Naturally occurring attenuated viruses (e.g.
turkey herpes virus for Marek's disease) • Vaccines produced by serial passage in cell culture (e.g. canine distemper) • Vaccines produced by serial passage in heterologous host animals (e.g. hog cholera) • Vaccines produced by selection of cold adapted mutants and reassortants (e.g. flu) |
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Types of non-replicating native
antigen vaccines |
• Inactivated whole virions ("killed virus
vaccines", e.g. BVD) • Native viral subunits (e.g. flu) • Purified native viral proteins (hepatitis B) |
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Recombinant DNA / Innovative
Vaccines |
• Gene deleted mutants (e.g.
psuedorabies) • Viral vectors (e.g. rabies antigen in vaccinia virus vector) |
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Adverse effects of vaccines in
pregnant animals |
• Live virus vaccines not recommended
• Abortions, tertogenic effects (e.g. BVD vaccine) |
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Timing of vaccination
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• Passive immunity interference
• Right timing important • 8-16 weeks - dogs, cats • 12-24 weeks - farm animals |
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Factors affecting vaccine
efficacy, failure, and safety |
• Vaccine strain may be different than infecting
virus (serotypes) • Passive immunity • Under- or over-attenuation • Inappropriate handling and storage • Lack of surface (IgA) immunity • Insufficient dose - poor QC • Contaminating viruses |
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Attenuated virus vaccine:
Route of administration: Amount of virus in dose: Number of doses: Need for adjuvant: Duration of immunity: Antibody response: cell-mediated response: Heat lability: Interference by prior antibody: side effects: Use in pregnant animals: Reversion to virulence: cost: |
Route of administration:injection, inhalation, oral
Amount of virus in dose:low Number of doses:single, generally Need for adjuvant:NO Duration of immunity:many years Antibody response:IgG,IgA, cell-mediated response:good Heat lability:yes for most Interference by prior antibody:yes side effects:occasional, local,or systemic Use in pregnant animals:not advised but commonly done Reversion to virulence:rarely cost:low |
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INACTIVATED VIRUS VACCINE:
Route of administration: Amount of virus in dose: Number of doses: Need for adjuvant: Duration of immunity: Antibody response: cell-mediated response: Heat lability: Interference by prior antibody: side effects: Use in pregnant animals: Reversion to virulence: cost: |
Route of administration:injection
Amount of virus in dose:high Number of doses:multiple Need for adjuvant:yes Duration of immunity:generally one year or less Antibody response:IgG cell-mediated response:generally modest Heat lability:no Interference by prior antibody:usually no side effects:occasional, local Use in pregnant animals:yes Reversion to virulence:no cost:high |
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DNA VACCINE:
Route of administration: Amount of virus in dose: Number of doses: Need for adjuvant: Duration of immunity: Antibody response: cell-mediated response: Heat lability: Interference by prior antibody: side effects: Use in pregnant animals: Reversion to virulence: cost: |
Route of administration:injection
Amount of virus in dose:Nil Number of doses:single generally Need for adjuvant:no Duration of immunity:many years Antibody response:IgG cell-mediated response:good Heat lability:no Interference by prior antibody:apparntly no side effects:uncertain Use in pregnant animals:yes Reversion to virulence:no cost:high |
