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187 Cards in this Set

  • Front
  • Back
Definition of a virus:
• Obligatory intracellular parasite with
genetic material enclosed in a
protein shell
Individual virus particle
• Virion:
Protein coat surrounding the
nucleid acid
• Capsid:
Protein subunits that
make up the capsid
• Capsomer:
Lipoprotein coating
surrounding the capsid derived from
infected cell membrane
• Envelope:
Icosahedral symmetry
•12 vertices
•20 faces
•30 edges
Viral Proteins
• Structural:
Viral Proteins
• Structural: Part of the virus particle
• Virus architecture
• Protective coat
• Viral receptors
• Antibody response
Viral Proteins
• Non-structural:
Seen only in infected
cells
• Viral replication/enzymatic function
• Regulation
Viral lipids
• 20-55% of dry weight of enveloped
viruses
• 50-60% phospholipid, remaining
cholesterol
• Ether-chloroform sensitive
viral Carbohydrates:
Serve as components of:
• Viral glycoprotein “gp”
• Viral antigens
• Receptors
Virus Family:Aslarviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Aslarviridae
>size:large
>+/- envelope:+
>symmetry:icosohedral
>RNA or DNA:DNA
Virus Family:Poxviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Poxviridae
>size:large
>+/- envelope:+/-
>symmetry:complex
>RNA or DNA:DNA
Virus Family:Iridoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Iridoviridae
>size:large
>+/- envelope:+
>symmetry:Icosohedral
>RNA or DNA:DNA
Virus Family:Herpesviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Herpesviridae
>size:Medium
>+/- envelope:+
>symmetry:icosohedral
>RNA or DNA:DNA
Virus Family:Adenoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Adenoviridae
>size:Medium
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:DNA
Virus Family:Papoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Papoviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:DNA
Virus Family:Parvoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Parvoviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:DNA
Virus Family:Circoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Circoviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:DNA
Virus Family:Hepadnaviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Hepadnaviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:DNA
Virus Family:Retroviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Retroviridae
>size:Medium
>+/- envelope:+
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Reoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Reoviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Birnaviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Birnaviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Paramyxoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Paramyxoviridae
>size:large
>+/- envelope:+
>symmetry:Helical
>RNA or DNA:RNA
Virus Family:Rhabdoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Rhabdoviridae
>size:medium
>+/- envelope:+
>symmetry:Helical
>RNA or DNA:RNA
Virus Family:Filoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Filoviridae
>size:large
>+/- envelope:+
>symmetry:Helical
>RNA or DNA:RNA
Virus Family:Bornoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Bornovirdae
>size:small
>+/- envelope:+
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Orthomyxoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Orthomyxoviridae
>size:Medium
>+/- envelope:+
>symmetry:Helical
>RNA or DNA:RNA
Virus Family:Bunyaviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Bunyaviridae
>size:Medium
>+/- envelope:+
>symmetry:Helical
>RNA or DNA:RNA
Virus Family:Arenoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Arenoviridae
>size:large
>+/- envelope:+
>symmetry:Helical
>RNA or DNA:RNA
Virus Family:Coronaviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Coronaviridae
>size:large
>+/- envelope:+
>symmetry:Helical
>RNA or DNA:RNA
Virus Family:Arteriviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Arteriviridae
>size:small
>+/- envelope:+
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Picornaviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Picornaviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Caliciviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Caliciviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Astroviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Astroviridae
>size:small
>+/- envelope:-
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Togoviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Togoviridae
>size:small
>+/- envelope:+
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Flaviviridae
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Flaviviridae
>size:small
>+/- envelope:+
>symmetry:icosohedral
>RNA or DNA:RNA
Virus Family:Deltavirus
>size:
>+/- envelope:
>symmetry:
>RNA or DNA:
Virus Family:Deltavirus
>size:small
>+/- envelope:+
>symmetry:?
>RNA or DNA:RNA
Ten steps of viral replication
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
In general DNA viruses replicate in the _________ and RNA viruses replicate in the _____________
In general DNA viruses replicate in the _Nucleus_ and RNA viruses replicate in the _Cytoplasm_
DNA viruses families that replicate in the cytoplasm
Poxviridae
Asfarviridae
RNA viruses families that replicate in the nucleus
Retroviridae
Bornoviridae
Othomyxoviridae
Family:Poxviridae
Virus:Vaccinia virus
Receptor on target cell:
Family:Poxviridae
Virus:Vaccinia virus
Receptor on target cell:Epidermal
growth factor
receptor 1
Family:Retroviridae
Virus:HIV
Receptor on target cell:
Family:Retroviridae
Virus:HIV
Receptor on target cell:CD4 and more than 10 coreceptors
Family:Rhabdoviridae
Virus:Rabies virus
Receptor on target cell:
Family:Rhabdoviridae
Virus:Rabies virus
Receptor on target cell:Acetylcholine
receptor,
gangliosides,
phospholipids
Family:Orthomyxoviridae
Virus:Influenza A
Receptor on target cell:
Family:Orthomyxoviridae
Virus:Influenza A
Receptor on target cell:Sialic acid
containing
oligosaccharides
Family:Picornaviridae
Virus:Rhinoviruses
receptor on target cell:
Family:Picornaviridae
Virus:Rhinoviruses
receptor on target cell:ICAM-1
Types of virus infection of cells:
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
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)
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)
Non-cytocidal viruses:
• No CPE produced (e.g. some
retroviruses, non-CPE BVD)
• Viral persistence
• Long range effects
• Antigenic changes
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
viral caused Cell transformation
• Loss of contact inhibition
• Aneuploidy (abnormal chromosome
numbers)
pox virus inclusion bodies
cytoplasm
Herpes virus inclusion bodies
nulceus fragments
Reovirus inclusion bodies
cytoplasm inclusions that hug nucleus
Adeno virus inclusion bodies
nucleus fragments
Rabies virus inclusion bodies
cytoplasmic inclusions in neurons
K9 distemper inclusion bodies
cytoplasm and nucleus
Steps of viral pathogenesis
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)
Influenza viruses belong to this family
Orthomyxoviridae
Influenza Viruses
Important Concepts:
Influenza Viruses
Important Concepts:
• Segmented genome
• Antigenic variation
• Role of viral protein (HA) in
pathogenesis
• Some are zoonotic
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
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
Examples of human and animal
influenza viruses
Human: H1N1,H2N2,H3N2 Swine:H1N1,H3N2
Horse:H7N7,H3N8
Antigenic variation: changes in
HA molecule
• Antigenic drift:
minor changes
• Slow evolution
• Point mutations
• Immunological pressure
• Changes in more than 2 epitopes
Antigenic variation: changes in
HA molecule
• Antigenic shift:
major Ag change
• Abrupt change
• Mostly originate in China
Molecular basis of virulence and
pathogenicity of influenza virus
• Cleavability of HA by host protease
• Local infection vs. pantropic infection
• Gene constellation
Equine influenza H and N types:
type of infection:
H7N7: equine 1
H3N8: equine 2
Not much antigen change
Respiratory, aerosol infection
Equine influenza:
icubation period:
recovery:
• I.P. 1-3 days
• upper respiratory tract symptoms,
fever
• secondary bacterial infection
• recovery 1-2 weeks
Equine influenza vaccination
Vaccines - bivalent inactivated
vaccine
3 doses, 8-12 weeks apart
Race horses - every 3-6 months
Hong Kong Bird Flu
H5N1
Avian influenza:
• 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
Diagnosis of influenza
• Virus isolation
• Serology
Properties of Paramyxoviruses
• 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
Paramyxoviruses Important Diseases:
• 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
• Morbillivirus genus: Canine distemper host range and transmission
• Canidae - dog, fox, coyote, etc
• Procyonidae - raccoon, panda, etc.
• Mustelidae - mink, skunk, otter, etc.
• Transmission:
• All secretions, excretions
• Direct contact, droplet infection
Canine distemper susceptibility
• Young - more susceptible
• 4-6 months ( maternal Ab
• Urban dogs - more frequent
• Rural - less frequent but more
catastrophic
Canine distemper symptoms and lesions
• Biphasic febrile response
• Anorexia, conjunctivitis, nasal
discharge
• Respiratory: bronchitis, tonsillitis,
cough, bronchopneumonia
• GIT: vomiting, diarrhea
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)
Canine distemper late complications
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
Canine distemper neurological symptoms
seizures
ataxia
paresis
Canine distemper mortality:
30-80% surviving dogs have CNS sequelae
Canine distemper diagnosis
• Viral infected cells by IF
• Histopathology:
• Inclusions bodies - brain, lung,
stomach, bladder, etc.
canine distemper immunity
• Recovery with life long immunity
• Vaccination - live virus vaccine - 8,
12, 16 weeks
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
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
Viral - bacterial synergism in
disease
• Shipping Fever: multi-factorial
etiology
• Stress factors:
• Transport
• Exhaustion, starvation
• Dehydration, chilling, overheating
• Dusty conditions
• Over-crowding
• Nutritional changes
Shipping fever
viruses:
bacteria:
•Viruses
• PI3
• IBR
• BVD
• BRSV
• Bacteria
• Pasteurella - Bronchopneumonia
Togaviridae General Properties
• Two genera, Alphavirus and Rubivirus
• Only Alphavirus is insect-borne
• Enveloped, spherical
• Positive-sense RNA genome
• Cytoplasmic replication
• Budding from plasma membrane
Togaviridae important diseases/viruses
• Eastern equine encephalitis virus
• Western equine encephalitis virus
• Venezuelan equine encephalitis virus
Arboviruses general
• 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)
Recent increased arboviral
activity due to:
• Geographic intrusion, deforestation
• Irrigation, urbanization
• Increases in long distance travel
• New routing of bird migration
Equine encephalitis pathogeneis:
• 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.
• Eastern equine encephalitis virus
• Western equine encephalitis virus
• Venezuelan equine encephalitis virus
control and diagnosis
Diagnosis
• Virus isolation
• Serology
Control
• Vaccination
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
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
Flaviviruses important virues
• 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
BVDV has only a single ______ but multiple _______ occur
BVDV has only a single _serotype_ but multiple _strains_ occur
Two biotypes of BVDV
Two biotypes based
on CPE
• Cytopathic (CP)
• Non-cytopathic (NCP)
• NCP can convert into CP virus
Genotypes of BVDV
Genotypes: by genetic analysis
• Classical BVDV
• Hog cholera virus or CSFV
• "True" border disease virus
• BVDV type II and some BDV
BVDV Clinical picture and pathology:
mostly subclinical
• In acute cases: Diarrhea
– Erosive lesions in GIT
– Sometimes death
• Fetal infections
• Congenital problems
• Viral persistence
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
Events leading to mucosal disease
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
Mucosal disease (MD) –2 steps
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)
BVDV diagnosis and control
• Virus Isolation and serology
• Vaccination
• Test and get rid of persistently infected
cattle
• Persistently infected cattle are antibody
negative, virus positive
_________ virus is a common cell culture contaminant
BVDV
In BVDV persistently infected calves are __________
poor doers
Retroviruses
Important Concepts:
• Reverse transcriptase
• Chromosomal integration of viral genome
• Antigenic variation
• Viral persistence
• Oncogenesis
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
Retroviruses Important Disease/viruses
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
Type C Retroviruses
• Endogenous - No pathology
• Exogenous replication competent - FeLV
• Exogenous defective - FeS
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
FeLV Disease Progression and
Pathogenesis
• Majority of cats - effective immune
response - recovery
• Some cats - ineffective immune response
- virus persistence - disease
Predominant form of neoplasm in FeLV
- Lymphosarcoma
• Symptoms depend on location of lesion:
• Alimentary - vomiting, diarrhea
• Thymic - coughing, dysphagia, dyspnea
• Multicentric - many organs
• Lethargic, anorexia, weight loss
FeLV Effect on hematopoietic system
• Lymphoblastic leukemia
• Erythroleukemia
• Myelogenous leukemia
• Anemia
Immunocomplex disease caused by FeLV
• Glomerulonephritis
Common results from Immunosuppression in FeLV
• Secondary infections
• Repeated infections
• Chronic stomatitis
• Gingivitis
• FIP, etc...
FeLV Diagnosis and control
Diagnosis
• IFA
• ELISA
Control
• Killed virus vaccine
Feline sarcoma virus
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
FIV genral
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
FIV diagnosis and control
Diagnosis
• ELISA
Control
• vaccines
Bovine Leukemia Virus (BLV)
• mostly _______________
• __% persistent lymphocytosis
• multistage process
• mostly asymptomatic
• 30% persistent lymphocytosis
• multistage process
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)
Equine Infectious Anemia (EIA)
• Horses
• Insect transmission
• Antigenic variation
• Immune complex disease
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
Picornaviruses Important Diseases/Viruses
• Apthovirus genus: Foot and mouth
disease virus
• Enterovirus genus: Swine vesicular
disease virus
• Many other genera: Eg. Rhinovirus
viruses that cuase Vesicular Diseases
• 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
vesicular diseases hosts and susceptiblity
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
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
foot and mouth all _________ animals are susceptible
All cloven hooved animals susceptible
• Cattle
• Swine
• Sheep
• Goat
• Buffalo
• Wildlife - 70 species of 20 families
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
Foot and mouth viral entry
• Inhalation of droplets
• Ingestion
• Contact
• Infected semen
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
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
Foot and mouth in swine sheep and goats
• Swine: Foot lesions more serious
– Vesicles on snout
• Sheep and Goats: milder disease,
lameness
Foot and mouth immunity
• IgM, broad protection
• IgG, type specific
• ~1 year, not life long
Foot and mouth diagnosis
• Virus isolation and typing
• ELISA
• Virus neutralization
Foot and mouth epidemiological considerations
• Rapid spread - quarantine measures
• Severity - endemic vs. virgin soil
epidemics
• Airborne spread - materiological modeling
Vesicular stomatitis virus (VSV) serotypes and hosts
Vesicular Stomatitis Virus (VSV)
Two serotypes:
• VSV - Indiana
• VSV - New Jersey
Broad host range virus:
• Cattle, Horses, Pigs
Vesicular stomatitis virus occurrence in the USA
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
Where is vesicular stomatitis virus endemic
mexico and central america
Transmission of vesicular stomatitis virus
Transmission
• Contact
• Insects, milking machines
• Sandflies
Vesicular stomatitis virus
lesions:___ ____ ___ ___ ___
symptoms:_______ ________
IP:_________
Symptoms, lesions
• IP - 1 to 5 days
• Fever
• Salivation
• Vesicular lesions - tongue, mouth, teats,
coronary band, hoof
Vesicular stomatitis virus immunity
Immunity
• Not life long
• Strain specific
• IgA Important
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
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)
San Miguel Sea Lion Virus
• 1972 - California
• Seals, sea lions - vesicular lesions of
flippers
• Pacific walrus, bottle nosed dolphin
• Antigenic variants generated in sea
animals
Rhabdoviruses (rabies)properties
• Enveloped, bullet shaped
• Ss negative-sense RNA genome
• Cytoplasmic replication
• Budding through plasma membrane
Rhabdoviruses important diseases/viruses
• Genus Lyssavirus: Rabies virus
• Genus Vesiculovirus: Vesicular stomatitis
Rabies genral
• 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
Rabies transmission
• Bites, infected saliva
• Scratches, open wounds
• Vampire bats
• Bat caves - inhalation
• Feeding on infected animals
Rabies pathogenesis general
• Neurotropic virus
• Incubation period
– 14-90 days, sometimes longer
– Site and severity of bite affects IP
clinical forms of rabies
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
Rabies first phase of infection
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
Rabies second phase of infection
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
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?
Rabies diagnosis
Diagnosis
• FA test, brain tissue
• Inclusion bodies
• PCR
Rabies treatment and ptophylaxis
• Inactivated virus vaccine
• Attenuated virus vaccine
• Pre-exposure immunization
• recommended for all high risk groups
• Post exposure vaccination
• Rationale and mechanism
Poxviridae virus properties
• Mostly brick shaped with complex
symmetry
• Large in size
• Large ds genomic DNA
• Cytoplasmic replication
• Release by exocytosis and cell lysis
• Viral Vector
poxvirus important diseases/viruses
• Cowpox virus
• Vaccinia virus
• Sheeppox virus
• Swinepox virus
• Orf virus
• Pseudocowpox virus
Poxvirus infections
• Localized and surface infections
• Some also cause systemic disease
• Dermatotropism is a general feature
Transmission of pox viruses
• Contact
• Skin abrasions
• Droplet infections - sheep pox
• Insect transmission (mechanical):
swine pox, fowl pox
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
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
Pseudocowpox
• Nodular, proliferative lesions
• Papule - dark red scab with
extended edges
• Center umbilicated -
desquammation - ring or "horse
shoe" scab
Swinepox
• Lesions on the belly
• 1-2 cm in diameter
• Pig louse transmission
pox virus systemic diseases
• Sheeppox and lumpy skin disease
viruses
• Problematic in other regions of the
world
• Skin and visceral lesions
• Cell associated viremia
Papilloma virus properties
• Non-enveloped, spherical
• Circular ds DNA genome
• Nuclear replication
• Episomal DNA, may be oncogenic
• Virus maturation in differentiated
cells
Papilloma virus important diseases/viruses
• Bovine papilloma
• Equine papilloma
Canine papilloma
Bovine papillomatosis (warts) types and antigenic groups
6 types
2 antigenic groups
1,2,5
3,4,6
Bovine papillomatosis general
• Viral DNA remains episomal
• DNA replication basal squamous
epithelial cell
• Viral maturation in terminally
differentiated keratinized cells
Bovine papillomatosis sysmptoms and lesions
• Young animals - higher incidence
• Viral entry through skin abrasions
• Head, neck, shoulders, udder,
genitalia
• IP - 4 to 6 weeks
papilloma leison
• Fibrous core
• Large warts, abrasion, bleeding
• ~ 4 - 6 months - spontaneous
regression
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
Papilloma Control and treatment
• Surgical removal
• Cryotherapy
• Autologous vaccines
Impact of vaccination in the
control of viral diseases
• FMD, hog cholera eradicated
• Incidence of many diseases
decreased
Basis for immunity with viral
vaccines
• Humoral immunity: neutralizing antibody
• Cell mediated immunity: cytotoxic T cells
Varieties of viral vaccines
• Live virus vaccines
• Non-replicating native antigen vaccines
• Recombinant DNA / Innovative Vaccines
Types of live virus vaccines
• 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)
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)
Recombinant DNA / Innovative
Vaccines
• Gene deleted mutants (e.g.
psuedorabies)
• Viral vectors (e.g. rabies antigen in
vaccinia virus vector)
Adverse effects of vaccines in
pregnant animals
• Live virus vaccines not recommended
• Abortions, tertogenic effects (e.g. BVD
vaccine)
Timing of vaccination
• Passive immunity interference
• Right timing important
• 8-16 weeks - dogs, cats
• 12-24 weeks - farm animals
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
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
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
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