Exam 1 Material Flashcards
(214 cards)
1
Q
Define virus
A
A virus is a small collection of genetic code, either DNA or RNA, surrounded by a protein coat. A virus cannot replicate alone and must infect cells, using components of the host cell to make copies of itself. Often, this process kills the host cell and causes damage to the host organism
2
Q
What are some examples of viruses?
A
- Rabies
- COVID-19
- Smallpox
3
Q
Why is COVID-19 significant in virology?
A
The COVID-19 pandemic underscores the importance of understanding viruses and their global impact
4
Q
Who(m) was responsible for the CONCEPT of smallpox vaccination?
A
Lady Mary Wortley Montagu and Edward Jenner contributed to the concept of vaccination
5
Q
Who was responsible for the smallpox vaccine?
A
Edward Jenner (1749-1823)
- Investigated methods to protect against smallpox, leading to the development of the smallpox vaccine
6
Q
What was the global impact of smallpox before its eradication?
A
- In the 16th century, smallpox was widespread in Europe and devastated indigenous populations in the New World
- It caused approximately 400,000 deaths annually in Europe during the late 18th century
7
Q
Who is considered the father of microbiology and virology?
A
- Louis Pasteur (1822–1895): A French scientist who significantly contributed to microbiology, virology, and infectious diseases
- He developed vaccines for rabies and advanced pasteurization techniques during an era when diseases like tuberculosis and typhoid fever were widespread
8
Q
What was the first virus discovered in vertebrates?
A
Foot-and-mouth disease virus, discovered by F.A.J. Loeffler and P. Frosch in 1898
9
Q
What are Koch’s postulates?
A
- Robert Koch and Louis Pasteur jointly proposed the germ theory of disease in the 1880s.
Koch’s postulates include:
- The agent must be present in every case of the disease
- The agent must be isolated and grown in vitro
- The disease must be reproduced in a healthy host after introducing the agent
- The agent must be recoverable from the newly infected host
10
Q
What advancements contributed to the study of virology?
A
- Discovery of cell culture for viruses
- Unraveling the structure of DNA
11
Q
Who discovered the swine influenza in 1931?
A
Shope
12
Q
Who(m) developed the polio vaccines in the 1950s?
A
Salk and Sabin
13
Q
Who discovered the feline parvovirus in 1965?
A
Johnson
14
Q
When was the smallpox eradicated globally?
A
1980
15
Q
Who(m) discovered HIV in 1984?
A
Montagnier and colleagues
16
Q
When was rinderpest eradicated globally?
A
2011
17
Q
Who was the father of science of microbiology, virology, & infectious diseases?
A
Louis Pasteur
18
Q
Who(m) discovered the foot and mouth disease virus?
A
Loeffler & Frosch with Robert Koch
19
Q
Who(m) proposed the ‘germ theory’?
A
Robert Koch & Louis Pasteur
20
Q
What features led to the eradication of smallpox and rinderpest?
A
- Development of effective vaccines providing long-lasting immunity
- Availability of reliable diagnostic tests
- Lack of wildlife reservoirs or carriers for these diseases
21
Q
What challenges exist in developing an HIV vaccine?
A
- HIV is unique because no one has ever recovered from it.
- The Mosaico trial (2019–2023) showed no significant difference in infection rates between the vaccine and placebo groups
22
Q
What is the Human Genome Project? Who led it?
A
- Initiated in 1990 and completed in 2003
- Led by John Craig Venter, who also transfected a cell with a synthetic chromosome
23
Q
What are some emerging viral threats?
A
- West Nile Virus
- Avian Influenza H5N1
- Canine Influenza (H3N8, H3N2)
- Coronaviruses
- African Swine Fever (ASF)
- Highly Pathogenic
- Avian Influenza (HPAI)
24
Q
How does African Swine Fever (ASF) impact the U.S. pork industry?
A
- ASF is a deadly disease with no available treatment or vaccine
- An outbreak could devastate the U.S. pork industry, which supports over 613,800 jobs and contributes $57 billion to the economy
25
What biosecurity measures help protect against ASF?
- Quarantine
- Biosecurity practices
- Depopulation of affected herds
26
What recent actions have been taken to combat avian influenza?
- Expansion of wild bird surveillance programs
- Depopulation of affected poultry flocks to prevent disease spread
- Increased public awareness and resources for biosecurity measures
27
What is a prion?
- It is a misfolded protein
- It is NOT a virus, bacteria, fungi, or parasite
28
Prion diseases in mammals affect?
The brain or other neural tissue, are progressive, untreatable, and always fatal
29
Most prion diseases are caused by?
The prion protein (PrP), but in 2015, alpha-synuclein prions were linked to multiple system atrophy (MSA)
30
Prion aggregates are resistant to?
Denaturation by chemical and physical agents, making them difficult to destroy through disinfection or cooking
31
Prion diseases are?
Proteopathies (diseases of structurally abnormal proteins)
32
What are examples of prion disease?
- Creutzfeldt-Jakob disease (spongiform degeneration in the brain)
-Scrapie in mice (neural tissue staining with prion protein)
33
What are the key components of virus structure?
- Capsid
- Nucleic acids
- Envelope
- Viral proteins
34
Define capsid
Made of capsomeres (glycoproteins) to protect RNA or DNA
35
Define nucleic acids
Either DNA or RNA
36
Define envelope
Acquired from the host cell; provides additional protection and aids in infection
37
Define viral proteins
Lock and key interaction with host cell receptors to initiate infection
38
What are the types of viral symmetry?
- Isometric
- Helical
- Bullet-shaped
- Spherical
- No recognized symmetry
39
Define the isometric viral symmetry and give an example
Capsid with 20 triangular faces (e.g., herpesviruses)
40
Define the helical viral symmetry and give an example
Tubular structure with coiled nucleic acid (e.g., rabies)
41
Define the bullet-shaped viral symmetry and give an example
Unique bullet-like appearance (e.g., rabies)
42
Define the spherical viral symmetry and give an example
Circular capsid structure (e.g., influenza, coronaviruses)
43
Define the no recognized symmetry viral symmetry and give an example
Includes complex (e.g., smallpox) and filamentous viruses (e.g., ebolavirus)
44
What is the role of the viral capsid?
- Protects the fragile nucleic acid genome from:
- Physical damage (e.g., shearing forces)
- Chemical damage (e.g., UV irradiation)
- Enzymatic damage (e.g., nucleases)
- Plays a role in initiating infection by delivering the genome to interact with the host cell
45
How does viral taxonomy classify viruses?
- Morphology of the virion, capsid, and envelope
- Genome type (RNA/DNA, single/double-stranded).
Serological relationships (serotypes)
- Replication strategy
46
How does virus structure affect disinfection and transmission?
- Heat sensitivity depends on protein denaturation (enveloped viruses are more sensitive)
- Extreme pH levels can destroy viruses
- Lipid solvents disrupt envelopes, making enveloped viruses more vulnerable
- Radiation, UV light, and certain chemicals can inactivate viruses
47
What are capsid proteins?
Structural proteins and non-structural proteins
48
How do structural proteins function?
Provide viral stability and attachment; antibodies target these proteins
49
How do non-structural proteins function?
Involved in viral replication and can differentiate vaccinated from naturally infected animals
50
What are "promiscuous" and "plastic" viruses?
- Promiscuous Viruses: Infect multiple species (e.g., rabies)
- Plastic Viruses: Adaptable to environmental changes due to genetic diversity (e.g., influenza)
51
How does SARS-CoV-2 infect host cells?
SARS-CoV-2 binds to the ACE2 receptor, present on epithelial cells in the intestine, respiratory tract, and kidneys
52
What is the viral life cycle?
1. Attachment: Virus binds to host cell receptor
2. Penetration: Virus enters the host cell
3. Uncoating: Viral genome is released
4. Transcription and Translation: Host machinery produces viral proteins
5. Replication: Viral genome is duplicated
6. Assembly: New virions are formed
7. Release: Virus exits the host cell to infect others
53
What methods are used to grow and study viruses?
- Infecting cell cultures, embryonated eggs, or animals (rarely used now)
- Cell cultures have advanced virology significantly over the last century
54
How are viruses grouped based on epidemiological criteria?
1. Enteric viruses
2. Respiratory viruses
3. Arboviruses
4. Oncogenic viruses
55
Define enteric viruses
Transmitted via ingestion (fecal-oral route); replicate in the intestinal tract
56
Define respiratory viruses
Acquired via inhalation or fomites; replicate in the respiratory tract
57
Define arboviruses
Transmitted by arthropod vectors (e.g., mosquitoes)
58
Define oncogenic viruses
Persist in specific tissues and may cause cancer
59
Define strain
Well-characterized virus with specific properties (e.g., virulence)
60
Define isolate
Virus recovered from a particular host or location
61
Define serotype
Variation within a virus that elicits unique antibody responses, meaning no cross-immunity (e.g., foot-and-mouth disease)
62
What is the difference between pathogenicity and virulence?
Pathogenicity is the ability of a virus to cause disease, while virulence is a relative measure of a virus's pathogenicity (e.g., strain A is more virulent than strain B)
63
Are virulence and pathogenicity related to infectivity and transmissibility?
No, virulence and pathogenicity are unrelated to infectivity and transmissibility
64
Can similar viruses have markedly different virulence? Provide an example
Yes, different serotypes of avian influenza viruses can have markedly different virulence
65
What is a strain in virology?
A strain is a well-characterized virus that may have distinct properties, such as virulence
66
Define an isolate in virology
An isolate is a virus recovered from a specific host or location
67
What is a serotype, and how does it relate to immunity?
A serotype is a subgroup of viruses sharing antigens recognized by antibodies. However, immunity to one serotype does not confer immunity to another
68
Provide examples of viruses with distinct serotypes
Foot-and-mouth disease, bluetongue, dengue, and influenza
69
What factors influence the outcome of viral exposure or infection?
- Method of transmission
- Number of infecting particles (dose)
- Virulence of infecting particles (genetics)
- Speed of viral replication and spread
- Degree of cellular damage
- Effectiveness of host defenses
70
What are possible effects of viruses on host animals?
- Acute clinical disease
- Subclinical disease (inapparent infection)
- Induction of cancer
- Induction of chronic progressive disease (especially of the CNS)
71
How does a virus enter a host cell?
Virus entry depends on the presence of appropriate cell receptors
72
What are the cellular effects caused by viruses?
- Direct damage (cell death/apoptosis)
- Paralysis
- Immune deficiency
- Disruption of normal cell functions (e.g., protein synthesis, secretion, membrane trafficking)
- Immune responses to virus-infected cells
- Cytokine release by immune cells
- Virus hijacking host genes
73
What determines the host range and tissue tropism of a virus?
The nature, number, and distribution of host cell receptors
74
How does a virion enter a host cell?
Through endocytosis or fusion with the plasma membrane
75
What process releases the viral genome into the cytoplasm?
Uncoating
76
What factors determine the outcome of a virus-host encounter?
The virulence of the infecting virus and the susceptibility of the host, influenced by genetic, environmental, and immunological factors
77
List host factors influencing pathogenesis
1. Genetic factors (species, breed, tissue susceptibility)
2. Age (neonate vs. geriatric)
3. Hormonal influences (e.g., pregnancy)
4. Living conditions (e.g., crowding, temperature)
5. Concurrent infections
6. Exposure to vectors
7. Immunity (innate, passive, or acquired)
78
What is viral tropism?
Viral tropism is the preference of a virus for certain cell types, tissues, or hosts
79
Provide examples of tropism in viruses
1. Rabies virus: neurotropic (targets CNS)
2. Malignant catarrhal fever: vascular system
3. Bovine virus diarrhea: lymphoid tissues
80
What are the two principal types of viral infections?
1. Localized infections (limited to the site of entry)
2. Systemic infections (spread to various organ systems)
81
What conditions can lead to systemic infections?
Disruption of the basement membrane, underlying cell infection, and entry of the virus into the bloodstream
82
What are examples of variations in viral infections?
- Inapparent infections
- Immunopathological disease
- Congenital infections
- Persistent & latent infections
- Slow virus infections
- Oncogenicity
83
Give an example of an inapparent infection
COVID-19 reservoirs
84
Give an example of an immunopathologic disease
Feline Infectious Peritonitis
85
Give an example of a congenital infection
Feline Panleukopenia
86
Give an example of a persistent & latent infection
Bovine Rhinotracheitis
87
Give an example of a slow virus infection
FIV
88
Give an example of an oncogenic virus
Feline Leukemia Virus (FeLV)
89
How do congenital infections occur?
Viral transmission during the viremic phase of the dam, causing defects, fetal death, or persistent infections
90
What is a latent infection? Give an example
A persistent infection where the virus remains dormant but can be reactivated (e.g., Herpesvirus)
91
What is the significance of inapparent infections?
They serve as unrecognized sources for viral spread
92
What are the main components of the study of veterinary virology?
- Nature and
- Classification of Viruses
- Viral Replication
- Pathogenesis
- Diagnosis
- Vaccination
- Epidemiology
93
Why is laboratory diagnosis important for infectious diseases?
- Recognize new diseases and agents (emergence/reemergence)
- Address zoonotic diseases (both vector-borne and non-vector-borne)
- Detect cross-species transmission of pathogens
- Identify changes in tissue tropism and immune evasion mechanisms (e.g., persistent infections)
- Confirm clinical diagnosis to guide treatment, vaccination, or control strategies
- Conduct herd testing or certification for regulatory and economic purposes
- Support livestock, poultry, aquaculture industries, and companion animal health
94
What species are typically addressed in veterinary diagnostic medicine?
- Companion animals (dogs, cats)
- Livestock (cattle, poultry, equine, sheep, goats, swine)
- Exotic pets (snakes, iguanas, turtles)
- Pocket pets (gerbils, hamsters)
- Birds
- Farmed fish (crawfish, shrimp)
95
What clients are typically addressed in veterinary diagnostic medicine?
- Veterinary teaching hospitals
- Private clinics
- State and federal animal health officials
- Owners, farmers, zoos, aquatic marine facilities
96
Why is it essential to diagnose viral diseases quickly?
- Allows effective control of disease
- Some diseases have characteristic or pathognomonic signs
- Economic implications may necessitate confirmation of diagnosis
- Suspicion of zoonotic or foreign animal diseases
97
What are the practical applications of diagnostic virology in clinical management?
- Provides rapid tests to meet client expectations
- Supports rational supportive treatments (e.g., antibiotics for secondary infections)
- Prevents disease spread within kennels, stables, or farms
- Advises clients about zoonotic risks
98
How does diagnostic virology contribute to disease prevention?
- Rapid diagnosis of epidemic diseases (e.g., foot-and-mouth, rabies) enables specific control measures
- Surveillance identifies emerging viruses and antigenic variants, guiding vaccine preparation
- Regulates international movement of animals and products
99
Why is clinical examination important in diagnosing viral infections?
- Helps identify pathognomonic signs in early stages
- Early-stage samples are more likely to provide a diagnosis
100
When are animals infectious, and what factors impact virus detection?
- Virus titers are highest at affected sites during early disease stages
- Viremia peaks often coincide with fever and precede other clinical signs
- Secondary bacterial infections may obscure viral presence in later stages
101
What precautions should be taken during sample collection and shipping?
- Follow safety rules to protect clinic staff, delivery personnel, and lab technicians
- Provide detailed clinical history to assist lab testing
102
What are the key techniques for diagnosing viral infections?
- Virus detection
- Viral antigen detection
- Gene sequence identification
- Antibody detection
103
Give examples of virus detection
- Virus isolation: Cell culture, laboratory animals (historical), egg culture
- Virus visualization: Electron microscopy
104
Give examples of viral antigen detection
- Immunohistochemistry/Immunofluorescence
- ELISA
- In situ hybridization
- Hemagglutination
105
Give examples of gene sequence identification
- PCR
- Whole genome sequencing
- Metagenomics
106
Give examples of antibody detection
- ELISA
- Immunofluorescent antibody tests
- Serum virus neutralization
- Hemagglutination inhibition
- AGID
107
How are virus isolations conducted using cell cultures and embryonate eggs?
- Cell cultures: Observe cytopathic effects (CPE) in monolayers stained with H&E
- Embryonate eggs: Use for influenza and pox virus isolation through allantoic and amniotic inoculation
108
What is the principle behind the hemagglutination assay?
Certain viruses (e.g., influenza) bind to red blood cells, causing agglutination, which is detected using round-bottom assay plates
109
How does ELISA detect viruses?
- Direct ELISA identifies viral antigens
- Indirect ELISA detects antibodies
- Includes controls to validate results and uses enzyme-mediated color changes for detection
110
What are the primary methods of virus detection?
- Virus isolation:
- Cell culture: Observes cytopathic effect (CPE)
- Laboratory animals: Mostly historical
- Egg culture: Traditional method
- Virus visualization: Using electron microscopy
111
What methods detect viral antigens?
- Enzyme-linked immunosorbent assay (ELISA)
- In situ hybridization:
- Immunohistochemistry/Immunofluorescence
112
Define enzyme-linked immunosorbent assay (ELISA)
Detects viral antigens
113
Define in situ hybridization
Localizes viral genetic material
114
Define immunohistochemistry/immunofluorescence
Identifies antigens in tissues
115
Which techniques detect viral gene sequences?
- Polymerase chain reaction (PCR)
- Whole genome sequencing
- Metagenomics
116
Define whole genome sequencing
Deciphers the entire genome
116
Define polymerase chain reaction (PCR)
Amplifies viral DNA or RNA
116
What are the methods for antibody detection?
- ELISA
- Immunofluorescent antibody test
- Serum virus neutralization (SN)
- Hemagglutination inhibition
- Agar gel immunodiffusion (AGID)
117
Define metagenomics
Identifies unknown pathogens
118
Define ELISA
Provides immediate positive/negative results
119
Define immunofluorescent antibody test
Uses fluorescent markers
120
Define serum virus neutralization (SN)
Measures antibody titer by plaque inhibition
121
Define hemagglutination inhibition
Detects antibodies that prevent RBC agglutination
122
Define agar gel immunodiffusion (AGID)
Often used in underdeveloped regions or specific diseases
123
What are the principles of serological testing?
Tests rely on a fourfold rise in antibody levels between acute and convalescent sera
124
What are the challenges of serological tests?
- Requires two samples, often delayed
- IgM or IgG identification may help distinguish recent vs. past infections
- Can be difficult and costly to collect paired sera
125
How does ELISA work?
1. Serum sample containing the antibody is tested
2. Viral antigen binds to a capturing antibody
3. Detecting antibody interacts with the antigen-antibody complex
4. Enzyme reaction produces a color change, indicating results
126
How is the serum virus neutralization test conducted?
1. Serially dilute the serum (e.g., 1:2, 1:4)
2. Add serum dilutions to cultured cells
3. Introduce virus to each well
4. Determine the highest dilution that prevents plaque formation (antibody titer)
127
What is the principle of hemagglutination inhibition?
- Some viruses (e.g., Influenza, Parvo) naturally agglutinate red blood cells
- Antibodies in patient serum inhibit this agglutination
128
How is antibody titer determined in a hemagglutination inhibition?
By identifying the last serum dilution that inhibits RBC agglutination
129
What are current uses of agar gel immunodiffusion (AGID)?
- Diagnostic tests in underdeveloped countries
- Screening for specific diseases (e.g., EIA in horses)
- Research and development of new diagnostics like ELISA
130
What factors influence the choice of diagnostic test?
- Disease stage
- Test sensitivity and specificity
- Need to confirm a notifiable disease
- Consultation with diagnostic labs for guidance
131
What are the limitations of diagnostic techniques?
- ELISA: Cost-effective but limited
- Virus isolation: Expensive but useful for vaccine development
- PCR: Requires advanced labs but widely used
- Sequencing and metagenomics: Sophisticated but expanding in availability
132
What should clinicians consider when interpreting lab results?
- Sample collection site and clinical presentation
- Sensitivity/specificity of tests
- Animal age, vaccination status, and colostrum antibodies
- Impact of reporting results (e.g., rabies confirmation)
133
What are the types of veterinary diagnostic laboratories?
- State VDLs: Serve agriculture, veterinary schools, and stakeholders
- National Veterinary Reference Labs (USDA): Include NVSL (Ames, IA) and FADDL (Plum Island, NY)
- Commercial labs: Antech, IDEXX
- Practitioner’s labs: In-house testing facilities
134
What is the mission of state VDLs?
To provide diagnostics, surveillance, teaching, research, and outreach
135
Why is laboratory diagnosis important?
- Detects emerging/reemerging diseases
- Confirms zoonotic and cross-species infections
- Guides treatment, vaccination, and control strategies
- Supports economic health of livestock, poultry, and companion animals
136
Is prior exposure to a virus required for antiviral immunity?
No, prior exposure is not required for antiviral immunity
137
What components of innate immunity contribute to antiviral defense?
Epithelial barriers (e.g., mucus), phagocytic cells (neutrophils, macrophages, dendritic cells), natural killer cells, and interferon production
138
What is the role of innate immunity in vaccination?
There is significant commercial interest in enhancing vaccination through effective products that augment innate immune responses
139
When does adaptive immunity develop?
Adaptive immunity develops only after exposure to a virus
140
Does adaptive immunity have memory?
Yes, it provides lifelong memory in response to some viral infections
141
What mechanisms are involved in adaptive immunity?
Adaptive immunity involves cellular and antibody (humoral) effector mechanisms, including T and B lymphocytes
142
How do innate and adaptive immune responses interact?
Cytokines, dendritic cells, natural antibodies, and certain T lymphocytes provide important bridging linkage between innate and adaptive immune responses
143
How do viruses evade the immune system?
- Viruses use several mechanisms, including:
- Establishment of persistent infection
- Latency in protected sites (e.g., nerve ganglia)
- Growth in immune cells
- Antigenic drift and shift
- Suppression of class I MHC molecules to prevent CTL-mediated killing
- Production of proteins that block cytokine signaling and antiviral pathways
144
What are the essential requirements for all vaccines?
Vaccines must satisfy requirements of efficacy, purity, potency, and safety
145
What are the main types of viral vaccines?
- “Historical Vaccines”: Jennerian vaccines (e.g., cowpox virus to protect against smallpox)
- “Work Horse Vaccines”:
- Live attenuated vaccines (modified live)
- Inactivated vaccines (killed)
- “New Generation Vaccines”:
- Recombinant and genetically engineered vaccines
- Nucleic acid vaccines (DNA and mRNA)
146
What are live attenuated vaccines, and why are they effective?
Live attenuated vaccines contain modified live viruses that replicate in the host, producing longer-lasting immunity similar to natural infection
147
What are the advantages of live attenuated vaccines?
- Single dose may be effective
-
Can be given via natural routes, stimulating local and systemic immunity
- Produces long-lasting immunity
- Inexpensive
148
What are the disadvantages of live attenuated vaccines?
- Possible reversion to virulence
- Potential spread to in-contact animals or fetus
- Contaminating viruses or mycoplasmas may be present
- May not be attenuated for all species
149
What are the advantages of inactivated vaccines?
- Stability
- No danger of spread
- No problem with viral interference
- Fatal viruses can be controlled
150
What are the disadvantages of inactivated vaccines?
- Multiple doses often required
- No local immunity or interferon produced
- High antigen concentration makes them expensive
- Immunity is often short-lived
- Non-inactivated virus may cause disease
151
What is the role of adjuvants in inactivated vaccines?
Adjuvants enhance the immunologic response by slowing antigen release and degradation, stimulating phagocytosis (e.g., aluminum hydroxide)
152
What are recombinant vaccines, and how are they developed?
Recombinant vaccines use genetically engineered methods to produce immunogenic proteins or attenuated pathogens (e.g., gene deletion)
153
What is a marker vaccine, and how does it work?
- Marker vaccines allow differentiation of infected animals from vaccinated ones (DIVA principle)
- They involve specific gene deletions, enabling the identification of naturally infected animals through antibody testing (e.g., pseudorabies vaccine)
154
What are examples of live attenuated and inactivated vaccines?
- Live attenuated: Canine distemper vaccine
- Inactivated: Eastern equine encephalomyelitis vaccine
155
How has molecular technology improved vaccine development?
Attenuation is now achieved through specific gene deletions rather than successive cell culture passages, increasing vaccine precision
156
What innovations are shaping vaccine technology?
- Advances include gene-deleted vaccines, recombinant vaccines, DNA/mRNA vaccines, and nanoparticle-based vaccines (e.g., virus-like particles, baculovirus-produced proteins)
157
What is the Differentiation of Infected from Vaccinated Animals (DIVA) principle, and why is it important?
DIVA (Differentiation of Infected from Vaccinated Animals) enables disease control and eradication by identifying naturally infected animals
158
How do virus-like particle (VLP) vaccines work?
VLP vaccines use recombinant technology to create antigenic proteins that assemble into empty capsids, stimulating immunity without containing infectious genetic material
159
Who introduced variolation using a related virus to confer immunity in 1798?
Edward Jenner
160
Who advanced the field of vaccinology with developments in live attenuated vaccines in the 1890s?
Louis Pasteur
161
What are the fundamental requirements all vaccines must meet?
- Efficacy
- Purity
- Potency
- Safety
162
How do mRNA vaccines like Moderna’s COVID-19 vaccine work?
- mRNA is synthesized from a template and instructs cells to make proteins
- Fragile mRNA is wrapped in lipid nanoparticles to protect it
- mRNA vaccines activate both innate and adaptive immunity
163
What are the characteristics of an ideal vaccine?
- Discriminates between infected and vaccinated animals (DIVA)
- Provides strong maternal immunity and overcomes colostral immunity
- Does not induce cancer when adjuvanted
- Offers broad-spectrum protection, preventing carriage, shedding, and transmission
- Stimulates effective, long-lasting immune responses
- Inexpensive to manufacture, simple to administer, and heat-stable
- Avoids reversion to virulence in live attenuated vaccines
164
Why might vaccines fail to protect?
- Improper use
- Genetic differences between animals
- Antigenic differences between vaccine strain and field strain
- Interference by maternal antibodies
- Administration after infection (Rabies is an exception)
165
What are the pros of deliberately infecting volunteers for vaccine trials (e.g., SARS-CoV-2)?
- Advances scientific knowledge with minimal risk
- Benefits global populations by aiding vaccine development
- Builds on a history of successful respiratory studies
166
What are the cons of deliberately infecting volunteers for vaccine trials (e.g., SARS-CoV-2)?
- Risk of fatal disease with no proven "rescue" drug
- Long-term consequences of mild infection
- Limited use due to emerging variants
- Challenges in reflecting older, at-risk populations
167
What are the the American Association of Feline Practitioners (AAFP) core vaccines?
- Panleukopenia, herpes, calici, rabies
- Intranasal vs. parenteral
- Age of vaccination
168
What are the the American Association of Feline Practitioners (AAFP) noncore vaccines?
FeLV, FIP, chlamydia, bordetella
169
What are the the American Association of Feline Practitioners (AAFP) injection sites?
- Leukemia = Left hind leg
- Rabies = Right hind leg
170
What are DNA vaccines, and how are they used in veterinary medicine?
- DNA vaccines use plasmid DNA to express antigenic proteins, inducing an antibody response
- Examples: A DNA vaccine licensed in 2005 protected horses from West Nile virus
- Currently, mRNA vaccines are more promising due to ease of manufacturing
171
Why is the antivax movement prevalent, and what role does veterinary medicine play?
- Vaccines are victims of their own success; memory of diseases has faded
- Pet owners, especially millennials, view pets as surrogate children, influencing vaccine hesitancy
172
What are key developments in antiviral therapy for veterinary medicine?
Limited use due to cost and lack of veterinary-specific evidence
173
What are examples of antiviral therapy for veterinary medicine?
- Acyclovir and Famciclovir: Treat feline herpes virus 1
- Tamiflu (oseltamivir): Experimental use for canine influenza and parvovirus
- Remdesivir and GS441524: Used for treating Feline Infectious Peritonitis (FIP)
174
What are the key concepts in vaccinology?
- The vaccine toolbox includes traditional and modern formulations like mRNA and recombinant vaccines
- Gene-deleted vaccines support the DIVA principle
- Non-mammalian poxvirus-vectored vaccines allow for targeted antigen presentation
- Vaccinology is rapidly evolving with advancements in mRNA, DNA, and synthetic protein technologies
- Vaccination remains essential in the absence of widely available antiviral therapies
175
What are some considerations beyond safety and efficacy in vaccine development?
Vaccine development involves:
- A long-term commitment of time and money for invention, testing, and marketing
- Reduced government involvement in vaccine research and development compared to the past
- Often marginal or non-commercial market viability
- Importance of marker vaccines in food animals
- Constant challenges posed by emerging diseases
- An indefinite need for vaccines targeting arthropod-borne diseases
176
What are the potential applications of vaccines in the future?
Vaccines may address both infectious and non-infectious issues
177
What are infectious applications?
- Animal diseases with economic and zoonotic implications
- Control of ectoparasites and endoparasites in domestic species, as well as terrestrial and marine wildlife
178
What are non-infectious applications?
- Contraception and sterilization
- Cancer prevention and treatment
- Immunomodulation therapies
- Gene therapy advancements
- Managing diseases like diabetes
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What is the disease associated with nervous signs in pigs and its cause?
The disease is Salt Poisoning, considered a Foreign Animal Disease
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What are the initial clinical signs of salt poisoning in pigs?
Thirst, constipation, skin irritation, and lack of appetite
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What nervous signs follow after water is suddenly reintroduced?
Ear twitching, aimless wandering, bumping into objects, dog-sitting, falling over sideways, and apparent deafness and blindness
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What unique behavior might affected pigs exhibit?
Moving in a circle using one foot as a pivot and experiencing convulsions approximately every seven minutes
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How is salt poisoning diagnosed?
By observing characteristic microscopic changes in the brain of deceased pigs
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What is epidemiology?
The study of determinants, dynamics, and distribution of diseases in a population
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What factors determine the risk of infection and/or disease?
Virus characteristics (e.g., antigenic variation), host factors (innate and acquired resistance), and behavioral, environmental, and ecological factors affecting virus transmission
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What are the transmission routes of viruses?
- Direct contact
- Indirect contact
- Common vehicle
- Airborne
- Arthropod borne
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Define direct contact for transmission of viruses
Licking, rubbing, biting, sexual acts
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Define indirect contact for transmission of viruses
Fomites (e.g., bedding, instruments, grooming equipment)
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Define common vehicle for transmission of viruses
Contaminated meat, water
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Define airborne for transmission of viruses
Droplets, aerosols, dander
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Define arthropod borne for transmission of viruses
Mechanical and biological transmission
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Define horizontal transmission
Between individuals in a population
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Define vertical transmission
From parent to offspring via intra-uterine infection, milk, or gametes
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What are collective terms for transmission?
- Iatrogenic
- Nosocomial
- Zoonotic
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Define iatrogenic
Caused by medical interventions
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Define nosocomial
Acquired in veterinary hospitals/clinics
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Define zoonotic
Transmissible from animals to humans
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What are the five mechanisms for ensuring the perpetuation of a virus?
1. Acute self-limiting infection
2. Persistent infection
3. Resistance of the virus to the environment
4. Involvement of an intermediate host
5. Congenital/vertical transmission
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How does an acute self-limiting infection perpetuate a virus?
- High transmission efficiency over a short time
- Short virus excretion duration to maintain susceptible hosts
- Immunity forces viral variants through antigenic drift and shift
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Define antigenic drift
Minor genetic changes; common in most viruses
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Define antigenic shift
Major genetic changes, often causing pandemics (e.g., human influenza)
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How does persistent infection contribute to virus perpetuation?
- Prolonged excretion reduces the need for a large susceptible population
- Allows coexistence of antibody and virus, often protecting the host from disease while remaining infectious
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What favors viral resistance to the environment?
- Survival in fomites or meat products
- Infections persist as new animals are born, compensating for those infected
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How do arthropods perpetuate viral infections?
- Arthropods serve as persistent vectors
- Biological transmission involves replication in the arthropod, spreading to salivary glands, and injecting during blood meals
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What are the types of hosts in viral perpetuation?
- Primary/maintenance host
- Reservoir host
- Dead-end host
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Define the primary/maintenance host
Natural host with long-term infection
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Define reservoir host
Wildlife that infect domestic animals
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Define dead-end host
Severely infected but with insufficient viremia for vector transmission
209
What causes seasonal variation in diseases?
- Arbovirus activity in certain climates
- Environmental and management factors (e.g., dog shows, feedlot conditions)
- Migration of wildlife reservoirs
210
What are Emerging Infectious Diseases (EIDs)?
Diseases that jump species or involve zoonotic viruses (e.g., SARS-CoV-2)
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What is molecular epidemiology?
The use of molecular biology methods (e.g., viral genomic sequencing) for epidemiological investigations
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How is big data used in tracking diseases like COVID-19?
Analyzing human contact data and infection risks using models like HealthMap and mobile data analysis
