Concurrent Block Flashcards
1
Q
Does a virus have RNA or DNA?
A
Can have either but not both
2
Q
What does the simple virus structure have?
A
Genome (RNA or DNA)
Capsid
Virion associated polymerase
3
Q
What does a complex virus structure have?
A
Genome
Capsid
Virion associated polymerase
Envelope
Glycoproteins
4
Q
What does is a virus envelope composed of?
A
Lipid-protein bilayer
5
Q
How are viruses seen?
A
Electron microscopy
6
Q
Are viruses parasites?
A
They are considered obligate intracellular parasites
7
Q
Where do DNA viruses replicate?
Name the exception
A
Nucleus
Except poxviruses
8
Q
Are DNA or RNA genomes more stable?
A
DNA
9
Q
Which type of genome has a higher error rate?
A
RNA
10
Q
How is a high error rate helpful?
A
More mutation > can see if mutation is beneficial
11
Q
What are the 2 types of capsids?
A
Icosahedral
Helical
12
Q
What type of capsid does not exist?
A
Naked helical capsid
13
Q
What are the properties of a naked capsid?
A
Environmental influences (heat, detergents, acids)
14
Q
Do naked or enveloped viruses retain infectivity upon dying?
A
Naked
15
Q
What gives rabies its distinctive shape?
A
The tightness of the envelope with a helical shape
16
Q
Which type of virus does not need to kill cells in order to spread?
A
Enveloped viruses
17
Q
Describe enveloped virus
A
Sensitive to environment and must stay wet during transmission
18
Q
What does a virus depend on a cell for?
A
Protein synthesis
Energy metabolism
Membrane biosynthesis (lipids)
19
Q
What makes a cell susceptible for viruses?
A
Corresponding receptors
20
Q
What makes a cell permissive to a virus
A
Provide intracellular components for virus replication
21
Q
What does a cell need to be infected by a virus?
A
Both susceptible and permissive
22
Q
What are the 5 steps of viral replication?
A
Uptake (susceptible)
Transport in the cell and uncoating
Replication in cytoplasm or nucleus
Assembly
Exit
23
Q
Where are receptor-binding viral proteins?
A
Viral surface (enveloped or naked)
24
Q
What receptor binding is reversible?
A
Protein
25
What receptor binding is irreversible?
Polysaccharide (must be cleaved)
26
What are 3 ways that a virus can be uncoated?
Plasma membrane
Endosome
Nuclear membrane
27
For viruses that fuse with the cell membrane, receptor-binding proteins require what?
A viral fusion protein
28
For viruses which fuse with the endosomal membrane what induces conformational change?
pH
29
For viruses that fuse with the cell membrane, what induces conformational change
NOT pH!!
(pH independent)
30
How do viruses use energy to transport into the cell?
Use microtubules
Some use actin cytoskeleton
31
What is another name for viral factories?
Inclusion bodies
32
What are viral factories?
Cytoplasmic or nuclear compartments (a factory for viruses)
33
How do inclusion bodies arise?
Rearrangement of host cell cytoskeleton
34
What are 3 mechanisms that enveloped viruses use to release from cell?
Budding
exocytosis
cell lysis
35
What is reverse fusion?
Budding and exocytosis by enveloped viruses
36
How do naked viruses release from cell?
Cell lysis (they build up in cell until it explodes)
37
What are the 4 layers of virus taxonomy?
Family
Genus
Virus
Strain/type/variant
38
What is pathogenicity?
Ability to cause disease
39
What is viral virulence
A measure of pathogenicity of viruses
40
What is infectivity?
Measure of ease of transmission
41
What is host resistance?
Ability of the host to control or eliminate viral infection or viral induced disease
42
What factors impact virulence?
Infectious dose
Route in infection
Tissue tropism
Virus dissemination
43
What is LD50?
Lethal dose required to kill 50% of infected animals
44
What is ID50?
Infectious dose required to infect 50% of inoculated animals
45
What is tissue tropism?
Cell types that can be infected by a virus
46
What allows canine distemper virus to have a large amount of species tropism?
CD150 on lymphocytes and Nectin 4 are common on many species
47
What is pantropism?
Ability to infect multiple cell types in multiple organs
Ability to use multiple receptors, permissivity on different cell types
Like CDV
48
What is antigenic drift?
Point mutations in gene segment
Can lead to epidemic
49
What is antigenic shift
Acquisition of new gene segments
Can lead to pandemic
50
What is virulent?
Insertion of cellular gene sequences which increase protein cleavage
51
What are some factors that impact host resistance or susceptibility?
Age, nutrition, husbandry conditions, stress, activity of the cell
52
How does activity of a cell influence viruses?
Replicating cells helps viruses proliferate
53
Describe papillomaviruses
Virus is latent in deeper epidermis, cells mature, produce viral proteins
54
What is important for initiating an infection?
1) susceptible cells (getting in)
2) Permissive cells (replicating)
3) Number of viruses (dose)
55
What is viremia?
Spread systemically
56
What is the most common portal of entry for viruses?
Respiratory tract
57
What does is a URT virus?
A virus that needs a colder environment to thrive
Infects the upper respiratory tract
There is an LRT as well
58
What are 3 mechanical barriers of the respiratory tract?
Ciliated cells
Mucus by goblet cells and subepithelial cells
59
What Ig are present in UPT?
IgA
60
Why might vaccinated in URT by better?
Cause a greater IgA response
61
What are the 2 routes of infection in the gastro-intestinal tract?
Oral infection
Hematogenic (blood) spread
62
What is the shorter incubation period?
Oral infection
63
What is the longer incubation period?
Hematogenic spread
64
How do oral infections transcytose?
M cells
65
Is intestine acidic or alkaline?
Alkaline
66
What are 2 rotavirus specific intestinal consequences of infection?
Intestinal hyper secretion (nsp4 protein)
Increased peristaltic
67
What are 2 examples of transmission through feces?
Rotavirus
Enteric coronavirus
68
How is Marek's disease shed on skin?
Feather follicle "feather dust" (virus)
69
What are viruses spread through the blood?
Bovine leukemia virus
Feline leukemia virus
Feline immunodeficiency virus
70
What causes fetal abortion to be more common?
More common in species where pregnancy is sustained by fetal progesterone (sheep) rather than maternal progesterone
71
What two things does abortion depend on?
Viral virulence
Gestation age
72
Which fetus is the most mature, immunologically?
Ruminants
73
Describe latency of EHV-1
Latency > nasal shedding (pregnant mares can abort) > infection of young horses > new hosts into cycle > latency
74
What 3 ways can the CNS be infected?
Olfactory nerve
Neurons to spinal cord to brain
Hematogenic
-----Usually a dead end! (except rabies with saliva)
75
How strong is CNS immune system
Very poor (astrocytes are not that good)
76
What is the MHC class I expression on neurons?
There isnt one...
77
What are consequences of CNS infections?
Transient infection
Lethal infection of neurons
Non-inflammatory infection
Progressive demyelination
78
What type of genome does rabies have?
RNA
79
What are the 2 cycles of rabies?
Urban (domestic)
Sylvatic (wildlife)
80
Describe rabies transmission
bite
replicates in muscle
enters nerves through acetyl-choline receptors
migrates to spinal chord to brain
spread to eyes and salivary glands
81
Do rabies animals become aggressive or tame?
They can become either! (Wildlife are usually tame!!)
82
What is first phase of rabies?
Prodromal phase (fever, headache, etc)
83
What is second phase of rabies?
Hyper excitability
bite bite
84
What is third/end phase of rabies?
Paralytic
85
What is treatment of rabies?
Washing wounds
Injection of rabies IgG (passive)
Vaccination (active)
86
What are #1 and #2 cases of rabies in USA?
1) Raccoons
2) Skunk
87
What is an acute infection?
Infection increases to clinical signs then decreases without long term effects
88
What is an example of acute infection?
Influenza A
89
What is a recurrent infection?
Infection goes up and down with clinical signs (like a roller coaster)
90
What is an example of recurrent infection?
BRSV
91
What is a chronic infection?
Build up of viral production then at some point show clinical signs
92
What is an example of chronic infection?
BVDV
93
What is a slow infection?
Used in prions that grow on a log scale
94
What is an example of slow infection?
Prions
95
What is a latent infection?
Initial clinical signs then low virulence levels but persist, then it comes back later down the line
96
What is an example of latent infection?
Herpesvirus
97
What are the 3 persistent infections?
Chronic
Slow
Latent
98
What are generalized infections?
Systemic infections
Infections of multiple organs, likely from more than one receptor
99
Describe CDV (canine distemper virus)
Often subclinical
Fever
URI symptoms
Vomiting/diarrhea
CNS issues
100
What can canine distemper infect?
Canids
Racoons
Mustelids
Big cats
101
Where does primary viremia occur for CDV?
Primary lymphoid organs
102
Where does secondary viremia occur for CDV?
CNS, epithelial, endothelium
103
What receptor does CDV use to bind to epithelial cells on the way out?
Nectin4
104
What are 4 severe clinical signs of CDV?
Primary pneumonia
Bacterial superinfections
Diarrhea
Bone remodeling and pitted enamel defects
105
What are 2 forms of CDV persistence?
CNS - old dog encephalitis
Overgrowth of skin on digital pads (hard pad disease)
106
What is incubation period of Newcastle disease?
2-15 days
107
Is Newcastle disease zoonotic?
YES
108
What are the 4 pathotypes of NDV?
Asymptomatic
Lentogenic
Mesogenic
Velogenic
109
What is lentogenic form of NDV?
Mild form in intestine, occurs with vaccines
110
What is mesogenic form of NDV?
intermediate form, respiratory and neurologic
111
What is vesogenic form of NDV?
Most virulent, neurotropic, viscerotropic
112
What are some clinical signs of NDV?
Drop in egg production
edema of head
greenish-dark diarrhea
113
What are diagnosis procedure for NDV?
Virus isolation
Serology
114
What are required actions with NDV?
Notification of authorities
Quarantine all suspect animals and premises
115
What are the 3 main hosts of influenza A?
Birds, pigs, humans
116
Where does influenza A normally originate?
Asia
117
What are the 2 origins into canine influenza A?
Avain (swine and human too)
and horses
118
Roughly how often does an influenza pandemic occur?
20-30 years
119
What is the influenza receptor?
Sialic acids on glycoproteins
120
What is the influenza receptor binding protein?
Hemagglutinin
121
Describe virus structure of canine influenza A
Enveloped
Helical capsid
RNA
122
What 2 things may cause a antigenic shift in CIV?
Hemagglutinin
Neuraminidase
123
Describe BRSV
RNA
Enveloped
Helical
124
What cattle get BRSV more commonly?
Adults
125
How many cattle get BRSV in a herd?
100%
126
What percent of cattle show clinic signs of BRSV?
20-50%
127
What percent of cattle die from BRSV?
5%
128
How is BRSV attached to mucous membranes?
Via F proteins on viral and host cell membranes
129
What is a respiratory disease complex?
Multifactorial (more than one pathogen, host immune status, environmental factors)
130
What animals do respiratory disease complexes occur in?
Cows, pigs, and dogs
131
How long after a stressful event does bovine respiratory disease complex (enzootic calf pneumonia) occur?
5-14 days
132
What pathogens (viral) are included in shipping fever?
BHV1
PI3
BRSV
133
What pathogens (bacteria) are included in shipping fever?
pasteurella haemolytica
Mycoplasma
Haemophilus somnus
134
What is vaccine protocol for shipping fever?
Vax 2-3 weeks prior to shipping, 24 hours after arrival
135
What is canine respiratory disease complex called?
Kennel cough
136
What viruses make up kennel cough?
PI5 then secondary bordetella bronchiseptica
Pneumococcal pneumonia
137
How do oral infections trancytos into epithelium?
M cells
138
What viruses are localized to the GI tract?
Coronaviruses
Rotaviruses
Turkey astro viruses
139
What are coronaviruses called that?
Because it has a crown-like appearance
140
Do corona viruses have DNA or RNA?
RNA
141
What does the fact that corona virus is an RNA virus mean?
high frequency of mutations
high frequency of RNA recombinations
142
What is the major cause of diarrhea in pigs?
TGE = Transmissible gastroenteritis of swine
143
When is TGE usually seen?
At farrowing time
144
**What is incubation period of swine?
1-3 days
145
What is outcome of piglets under the age of 7?
Death via vomiting and profuse watery diarrhea
146
Why are piglets more susceptible to TGE?
Gastric content is less acidic
Renewal of enterocytes is slow
Neonate immune system is immature
Neonates are susceptible to electrolyte imbalances
147
Where did porcine respiratory coronavirus come from?
TGE variant
148
What virus effects turkey astro virus?
Young animals (up to 3 weeks)
149
How are rotaviruses transmitted?
Oral-fecal
150
What has a faster incubation period, rota or corona?
Rotaviruses
151
What is the mechanism of diarrhea for rotaviruses?
Enterocyte destruction causing malabsorption
Stimulation of enteric nervous system causing increased motility
Milk increases osmotic dysregulation (milk not broken down)
152
What does parvo mean?
Small
153
What 3 viruses are part of parvoviridae?
Feline panleukopenia virus
Canine parvovirus
Mink enteritis virus
154
Where does parvo replicate?
Nucleus of actively dividing cells
>GI tract
155
What is something that can be seen on CBC for feline panleukopenia virus?
Leukopenia
156
What happens to a kitten if it is infected with feline panleukopenia in utero?
Cerebellar hypoplasia
157
What type of vaccine can be given for feline panleukopenia virus?
Modified live
158
What type of vaccine can be given for canine parvovirus 2?
Live-attenuated vaccine
159
Where did canine parvovirus 2 originate?
Point mutation of capsid protein of feline panleukopenia virus
160
What is chronic infection?
Virus is constantly replicating and often continuously shed
161
What is latent infection?
Period of time during the course of infection in which the virus cannot be detected
162
Are herpesvirus enveloped or non enveloped?
Enveloped
163
Are herpesvirus RNA or DNA?
DNA
164
Where are herpesvirus absorbed?
Mucous surface
165
Where does the herpes go once it is infected?
Doral root ganglia
166
When does the herpes virus come out of latency?
At immunosuppression
167
What does gallid herpes 1 infect?
Chicken
168
What is the incubation time for gallid herpes?
1 week! A lot different from Newcastle
169
Whatre the symptoms of gallid herpes?
Coughing, sneezing, ocular and nasal discharge
"Pump handle respiration (neck and head extended)"
"Fowl diphtheria (membrane formation at the tracheal bifurcation"
170
What type of vaccine is there for gallid herpes?
Live-attentuated and vector vaccines
171
Describe BVDV virus
Flaviviridae
RNA genome
Enveloped
172
What is primary replication area of BVDV?
Tonsilles
173
What is hemorrhagic syndrome?
Bleeding from mucosal surface
174
What happens if a BVD cow infects a cow within 90 days?
Likely embryonic deaths
175
What happens if a BVD cow is infected in late pregnancy?
Full-term calf with BVD antibodies
176
What happens if a BVD cow is infected mid pregnancy?
PI calf or birth defects
177
What is a common birth defect of BVD cows?
Torticollis
Cow with head tilted up
178
Does a PI calf have antibodies to BVD?
No
179
When does a cow get infected for a PI calf?
40-125 days
180
What physical signs may a PI cow show?
smaller
181
What happens if a cow with noncytopathic BVD gets cytopathic BVD? What is this called?
It dies, like DEAD
Mucosal disease
182
How to detect PI cows?
Antigen ELISA, PCR
183
What is feline coronavirus called?
FeCV
184
What do mutations of FeCV lead to?
FIP
FIP is not contagious then!
185
What does wet FIP have?
Ascites
186
What does dry FIP have?
No ascites
187
What is pathogenesis of FeCV?
Shedding of virus from queen
Persistent virus infection occurs
Mutation leads to FIP
188
How is FeCV passed along?
Saliva anf feces
189
Describe retroviruses
Enveloped, RNA (2 copies/virion)
190
How is retrovirus turned into DNA?
Using a reverse transcriptase (only time where DNA is made form RNA)
191
How is the DNA copy integrated into cellular genome?
Using integrase
192
Can FeLV be latent?
Yes, healthy carriers without infiltration of bone marrow
193
What is progressive infection of FeLV
Persistent infection of bone marrow, immunosuppression
194
What is similar to FeLV?
FIV
195
What are lentiviruses of sheep and goats?
Ovine lentivirus (OvLV)
Caprine arthritic encephalitis (CAE)
196
What does Ovine lentivirus effect?
Lungs (pneumonia)
197
How is EIAV transmitted?
Flies and iatrogenic
198
Is EIAV chronic?
Yes
199
What happens to blood in EIAV?
Anemia and petechial hemorrhage
200
What are transmissible spongiform encephalopathies?
Progressive, fatal, neurodegenerative diseases
201
What causes TSEs?
Prions
202
What are prions?
Abnormal, pathogenic, transmissible proteinaceous agent
203
How do prions work?
Encoded by the host and then expressed on cell membrane
204
What is life cycle of a prion?
Protein interacts with prion, prion converts protein into prion, prion heads back to convert more proteins to prions
205
What is an amyloid plaque?
Aggregation of prions
206
What is prion disease in sheep?
Scrapie
207
How to test for scrapie?
3rd eyelid biospie
208
What is a large symptom of scrapie?
Itching
209
What is prion disease in deer?
Chronic wasting disease (polydipsia/polyuria)
210
What is prion disease in cattle?
BSE
211
How did cows first get BSE?
Bone meal from scrapie sheep cadavers due to reduction in autoclaving temperature
212
What percent of emerging pathogens are zoonotic?
75%
213
What are the 4 important hosts for zoonotic viruses?
Primates, rodents, bats, birds
214
What is PRRS
Porcine Reproductive and Respiratory Syndrome
215
Describe PRRS virus
Arteriviridae, RNA virus
216
What are clinical symptoms of PRRS?
Reproductive failure
Post-weaning respiratory disease (fever, respiratory signs)
217
Describe West Nile Virus
Flavivirus, RNA, enveloped
Transmitted via mosquitos
218
What is post weaning multi systemic wasting syndrome in swine?
Circovirus type 2
Weaning 4-16 weeks
High fever
219
Describe foot and mouth disease virus
Non enveloped, RNA
220
When does virus excretion start for foot and mouth/
24 hours prior to clinical signs
221
What are clinical signs of foot and mouth disease
Smacking of lips, grinding, drooling, lameness, stamping
222
What are preventions of mosquito bites?
Repellents
Netting
mosquito control
