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Questions and Answers
What is the term for the circulation of viruses through the whole body, usually in the blood or lymph?
What is the term for the circulation of viruses through the whole body, usually in the blood or lymph?
Which of the following organs is typically affected during the secondary viraemia of a blood-borne virus?
Which of the following organs is typically affected during the secondary viraemia of a blood-borne virus?
What is the route of transmission of Canine Parvovirus?
What is the route of transmission of Canine Parvovirus?
What is the term for the initial replication of a virus in cells at the site of entry?
What is the term for the initial replication of a virus in cells at the site of entry?
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What is the site of major pathology during a viral infection?
What is the site of major pathology during a viral infection?
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What is the difference between acute and persistent viral infection?
What is the difference between acute and persistent viral infection?
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What is a necessary condition for a cell to be infected by a virus?
What is a necessary condition for a cell to be infected by a virus?
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Which type of cells does Canine parvovirus need to infect?
Which type of cells does Canine parvovirus need to infect?
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What can affect the disease severity of a viral infection?
What can affect the disease severity of a viral infection?
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How does Rabies virus reach the central nervous system (CNS) after infection?
How does Rabies virus reach the central nervous system (CNS) after infection?
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What is the role of the salivary gland in the transmission of Rabies virus?
What is the role of the salivary gland in the transmission of Rabies virus?
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Why does the immune system of the host have a reduced ability to detect and respond to Rabies virus infection in the brain?
Why does the immune system of the host have a reduced ability to detect and respond to Rabies virus infection in the brain?
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What is the primary function of the keratinized layer of skin in relation to viral infections?
What is the primary function of the keratinized layer of skin in relation to viral infections?
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Which of the following immune cells is NOT typically recruited to sites of inflammation in the skin?
Which of the following immune cells is NOT typically recruited to sites of inflammation in the skin?
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What is the term for the spread of viruses from the initial site of infection to other parts of the body through the bloodstream?
What is the term for the spread of viruses from the initial site of infection to other parts of the body through the bloodstream?
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Which of the following is NOT a route of transmission for viruses?
Which of the following is NOT a route of transmission for viruses?
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What is the term for the process by which viruses change to infect other hosts?
What is the term for the process by which viruses change to infect other hosts?
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Which of the following immune responses is NOT specific to a particular tissue or site?
Which of the following immune responses is NOT specific to a particular tissue or site?
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What is the primary reason why viruses cause pathology in hosts?
What is the primary reason why viruses cause pathology in hosts?
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What determines the viral fitness of a virus?
What determines the viral fitness of a virus?
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What is the term for the damage to host cells caused by a virus?
What is the term for the damage to host cells caused by a virus?
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Why do emerging viruses not have to evolve to become less pathogenic?
Why do emerging viruses not have to evolve to become less pathogenic?
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What is the term for the process by which a virus is released from an infected host?
What is the term for the process by which a virus is released from an infected host?
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What is the site of entry and exit for FMDV?
What is the site of entry and exit for FMDV?
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What is the primary factor that influences the ease of transmission and dose of insect-borne viruses in a livestock population?
What is the primary factor that influences the ease of transmission and dose of insect-borne viruses in a livestock population?
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Which of the following factors is NOT a viral factor that influences whether infection results in disease?
Which of the following factors is NOT a viral factor that influences whether infection results in disease?
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What is the characteristic of latent infections that allows the virus to reactivate in certain circumstances?
What is the characteristic of latent infections that allows the virus to reactivate in certain circumstances?
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Which of the following climatic conditions is likely to facilitate the flying of midges, increasing the transmission of insect-borne viruses?
Which of the following climatic conditions is likely to facilitate the flying of midges, increasing the transmission of insect-borne viruses?
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What is the outcome of an acute viral infection in a host?
What is the outcome of an acute viral infection in a host?
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Which of the following Practices is likely to increase the risk of transmission of insect-borne viruses in a livestock population?
Which of the following Practices is likely to increase the risk of transmission of insect-borne viruses in a livestock population?
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Study Notes
Viral Infection and Pathogenesis
- Viruses cause disease and pathology, which may be necessary for transmission
- Viral fitness is determined by survival and transmission
Stages of Viral Infection
- Entry into host through various routes (e.g., skin, respiratory tract, gastrointestinal tract)
- Local replication at site of entry
- Primary viraemia
- Replication at secondary site(s)
- Secondary viraemia
- Target organ replication
Mechanisms of Viral Pathology
- Direct effects: cytopathic effects (CPE) damage to host cells, resulting in cell death
- Indirect effects: virus-induced immune response, inflammation, and tissue damage
Viral and Host Factors Influencing Disease
- Viral factors: tropism, virulence, and level of replication
- Host factors: susceptibility, immune response, and genetics
Types of Viral Infection
- Acute infection: rapid, self-limiting infection cleared by the immune system
- Persistent infection: virus persists at low levels following recovery, with potential to reactivate
Latent Infection
- Virus persists in immune-privileged sites (e.g., neurons)
- Limited viral protein synthesis and infectious virus production
- Latency-associated transcripts reduce MHC expression and block apoptosis
Transmission of Viruses
- Faecal-oral transmission (e.g., FMDV)
- Salivary transmission (e.g., rabies)
- Blood-borne transmission (e.g., H5 avian influenza)
- Vector-borne transmission (e.g., insect-borne viruses)
Defences Against Viral Infection
- Physical barriers (e.g., skin, mucosal surfaces)
- Innate immune system (e.g., macrophages, neutrophils, natural killer cells)
- Adaptive immune system (e.g., antibodies, cytotoxic T cells)
Environmental Factors Influencing Viral Transmission
- Climatic conditions (e.g., high rainfall, temperature)
- Nutrition and feed (e.g., pasture, animal feed)
- Stocking density and animal husbandry practices
- Veterinary policy (e.g., vaccination programs)
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Description
This quiz assesses your understanding of the stages of viral infection, mechanisms of disease causation, and factors influencing disease outcomes. Test your knowledge of viral pathogenesis and how it affects the whole organism.
