Understanding Human Viruses: An Introduction

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Which type of response is specific to the virus?

Natural barriers response

Adaptive response (correct)

Innate response

Acquired immunity response

What is the term for the release of infectious virus from an infected host?

Viral spreading

Viral diffusion

Viral dissemination

Viral shedding (correct)

What type of transmission is most common for viruses?

Vector-borne transmission

Airborne transmission

Horizontal transmission (correct)

Direct transmission

What outcome of viral infection involves the presence of viral genome with no active replication?

Latent/Subclinical infection Signup and view all the answers

Which method primes the adaptive immune system to prevent viral infections?

Vaccination Signup and view all the answers

Which type of vaccine uses live attenuated viruses?

'Live attenuated' vaccine Signup and view all the answers

'Selective toxicity' in antiviral agents refers to their ability to:

Target specific viruses without harming host cells Signup and view all the answers

What is the primary characteristic of viruses?

They are acellular and nonliving Signup and view all the answers

What is the structure of a virion?

Genetic material surrounded by protein capsid and may have an envelope Signup and view all the answers

Which Baltimore class includes HIV?

<ul> <li>ss RNA with RT (Class VI)</li> </ul> Signup and view all the answers

What is the primary function of viral capsid?

Protection of the virus genome Signup and view all the answers

How many structural units (capsomeres) typically make up a viral capsid with icosahedral symmetry?

20 triangular faces, 12 vertices, 30 edges Signup and view all the answers

Which type of nucleic acid does Hepatitis B virus contain?

ds DNA with RT (Class VII) Signup and view all the answers

What is the host range of viruses?

Viruses can infect bacteria, plants, fungi, insects, animals, and humans. Signup and view all the answers

What is the characteristic feature of retroviruses?

They contain + ss RNA with reverse transcriptase (RT). Signup and view all the answers

Which step in viral pathogenesis involves the release of the virus through cell lysis or budding?

Release Signup and view all the answers

What determines the severity of viral disease?

Host response to infection Signup and view all the answers

Which type of transmission is associated with viral entry through ingestion of contaminated food and water?

Feco-oral transmission Signup and view all the answers

Which virus is primarily localized in the upper respiratory tract during its primary replication?

Rotaviruses Signup and view all the answers

What is the term for the presence of virus in the blood after spread and further replication, at a higher concentration?

Secondary viremia Signup and view all the answers

What are the mechanisms for spread of viruses throughout the host?

All of the above Signup and view all the answers

What factors contribute to the selectivity of productive infection (tropism) of viruses in certain tissues?

The selectivity of productive infection is TROPISM Factors Cellular receptors iii Host cellular proteases Temperature of replication pH lability Cellular transcription factors Anatomic barriers: cells must be physically accessible to the virus Local intrinsic and innate immune defenses Antibody and cellular immune response Eventual outcome depends on balance between: Clearance by host vs. Signup and view all the answers

What determines whether a viral infection remains local or becomes systemic during primary replication?

Host immune response Signup and view all the answers