Questions and Answers
What is a key structural feature that differentiates viruses from bacteria?
Which of the following diseases is indicative of smallpox?
In what year were leg deformities indicative of poliomyelitis first recorded?
Which of these is not considered a property of viruses?
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What is the general classification criterion for viruses?
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What type of viral infection is characterized by ongoing viral replication with few or no symptoms?
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Which virus is primarily associated with oncogenesis?
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Which method is NOT typically used in the laboratory diagnosis of viral infections?
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Which characteristic is associated with latent infections?
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What viral disease does NOT typically present any apparent disease symptoms?
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What is a mode of transmission for HIV?
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Which of the following viruses is known for airborne spread?
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What type of transmission involves sharing needles or blood products?
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Which virus is NOT typically associated with vertical transmission?
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Which of the following is a common method of virus release from an infected cell?
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What is a feature of enteral transmission?
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Which is an example of a virus that can be spread via fomites?
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What types of viruses are primarily formed within a host cell during infection?
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What is essential for a virus to enter a host cell?
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How do viruses typically transmit from one host to another?
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What do viruses rely on to process their genetic information into new virus particles?
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What is the role of viral enzymes during the replication process?
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What is one requirement for a virus to survive in the outside world?
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Which of the following is an example of a naked DNA virus?
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What is a helical RNA virus from the provided list?
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Which route is most commonly associated with viral entry into the body?
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Which of the following viruses is transmitted through food or water?
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What type of virus is Coxsackie virus classified as?
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Study Notes
Introduction to Virology
- Viruses differ from bacteria in structure, classification, and properties.
- Viral diseases have been recognized for centuries, with evidence of smallpox around 1500 BC and poliomyelitis-related leg deformities.
Virus Structure and Classification
- Viruses can be categorized based on their genetic material: DNA or RNA.
- DNA viruses:
- Examples include Papillomavirus (naked), Herpes viruses (enveloped), and Pox viruses (complex).
- RNA viruses:
- Examples include Picornaviruses (naked), Influenza (enveloped), and Retroviruses (enveloped).
Modes of Virus Entry
- Common routes of viral entry include:
- Inhaled droplets (e.g., rhinovirus).
- Ingestion through contaminated food or water (e.g., hepatitis A).
- Direct transfer from infected hosts (e.g., HIV).
- Arthropod bites (e.g., yellow fever).
Infection Acquisition
- Transmission methods:
- Direct contact (e.g., herpes viruses, HIV).
- Airborne spread (e.g., chickenpox).
- Parenteral exposure (e.g., HIV, hepatitis B and C).
- Contact with fomites (e.g., enteroviruses).
- Vectors (e.g., West Nile virus).
- Vertical transmission (e.g., HIV, rubella).
- Foodborne routes (e.g., hepatitis A).
Viral Replication Process
- A single host cell can produce thousands of viral particles.
- Enveloped RNA viruses (e.g., Influenza A) replicate by budding through the host cell membrane.
Consequences of Virus-Cell Interaction
- Viral infections can lead to various outcomes:
- Lysis of host cells, as seen in cold sores and chickenpox.
- Latent infections with non-replicating viruses (e.g., herpes viruses).
- Persistent infections with ongoing viral replication, resulting in tissue injury (e.g., hepatitis B and C, HIV).
- Induction of oncogenesis, linking certain viruses to cancer (e.g., human papillomavirus, EBV).
- Asymptomatic infections may occur (e.g., hepatitis G).
Diagnosis of Viral Infections
- Diagnosis relies on clinical features and laboratory tests, including:
- Histology and cytology techniques.
- Electron microscopy for direct examination.
- Detection of viral antigens in tissues and serum.
- Antibody testing (IgG, IgM detection).
- Virus isolation and amplification of viral DNA or RNA.
Important Virus Characteristics
- Viruses depend on host cells for replication and require cellular machinery to process genetic information.
- Virus envelopes or capsids play critical roles in host cell attachment and entry.
- Transmission typically occurs through respiratory droplets or contaminated food/water.
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Description
This quiz covers key aspects of virology, including the classification, structure, and properties of viruses. Learn how viruses differ from bacteria and explore the history of viral diseases. Test your understanding of these critical concepts in Infection and Immunity II.
