Introduction to Virology

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Questions and Answers

What is the primary function of the capsid in a virus?

To synthesize macromolecules

To carry out energy metabolism

To protect the viral genome from inactivation by nucleases (correct)

To attack the target cell by interacting with a specific cellular receptor

What is unique about the genetic material of a virus?

It is always double-stranded

It is surrounded by a lipid envelope

It is responsible for energy metabolism

It can be either DNA or RNA, but not both (correct)

What is the role of the viral attachment protein (VAP)?

To attach the virus particle to a target cell by interacting with a specific cellular receptor (correct)

To synthesize macromolecules

To carry out energy metabolism

To protect the viral genome from inactivation by nucleases

What is the characteristic of viruses that makes them obligate intracellular organisms?

They depend on the host cell for the synthesis of macromolecules Signup and view all the answers

What is the function of the nucleic acid in a virus?

To carry the genetic specificity to code for all the virus-specific macromolecules Signup and view all the answers

What is the characteristic of the protein coat that surrounds the nucleic acid genome?

It is composed of structural units called capsomers Signup and view all the answers

What is the process called when a virus acquires its envelope from the infected cell?

Budding off Signup and view all the answers

Which of the following viruses is primarily transmitted through faecal-oral transmission?

Enterovirus Signup and view all the answers

What is the term for the characteristic changes observed in cells infected with viruses?

Cytopathic effects Signup and view all the answers

Which of the following is NOT a common route of viral transmission?

Environmental transmission Signup and view all the answers

What is the term for the process of cultivating viruses in the laboratory using animal cells?

Cell culture Signup and view all the answers

Which of the following viruses is commonly associated with respiratory tract infections?

Adenoviruses Signup and view all the answers

What is the term for the study of the immune response to viral infections?

Immune response Signup and view all the answers

Which of the following is a common method of diagnosing viral diseases?

All of the above Signup and view all the answers

Which of the following viruses is primarily associated with epidemic outbreaks of gastroenteritis and can be transmitted through contaminated foods?

Norwalk-like Viruses Signup and view all the answers

What is the primary mode of transmission for Hand, Foot, and Mouth Disease?

Faecal-oral spread Signup and view all the answers

Which of the following viruses can cause life-threatening respiratory paralysis?

Poliovirus Signup and view all the answers

What is the primary method of diagnosis for Hepatitis A Virus?

Serum antibody tests Signup and view all the answers

Which of the following vaccines is an inactivated vaccine administered through IM injection?

Killed polio vaccine (Salk) Signup and view all the answers

What is the primary mode of transmission for Poliovirus?

Faecal-oral spread Signup and view all the answers

What is the primary treatment for Poliovirus infection?

Symptomatic treatment and respiratory support Signup and view all the answers

Which of the following viruses can cause a mild febrile illness lasting a few days, accompanied by headache and vomiting?

Poliovirus Signup and view all the answers

Study Notes

Viruses

Smallest infectious agents (20-300nm)
Obligate intracellular organisms, dependent on host cell for energy metabolism and synthesis of macromolecules
Contain either DNA or RNA as genetic material, never both
Surrounded by protein coat and sometimes a lipid- and glycoprotein-containing envelope

Basic Virus Structure

Nucleic acid carries genetic specificity to code for all virus-specific macro molecules
Capsid is a symmetric protein shell that encloses the nucleic acid genome
Composed of structural units (capsomers) visible in electron microscope
Functions: protect viral genome, determine antigenic characteristics, and responsible for structural symmetry

Envelope and Symmetry

Envelope is a lipid-containing membrane that surrounds some virus particles, acquired from infected cell through "budding off" process
Types of symmetry: Adeno viruses, Herpes viruses, MYXO viruses, RHABDO viruses, and Poxvirus

Viral Life Cycle

Six stages within host cell: Adsorption, Penetration, Uncoating, Macromolecular synthesis, Assembly, and Release

Cultivation of Viruses

Three common tissue cultures: Chicken egg culture, Cell culture, and Animal inoculation

Cytopathic Effects

Changes in size and shape, cytoplasmic inclusion bodies, nuclear inclusion bodies, cells fuse to form multi-nucleated cells, cell lysis, altered DNA, and transformation into cancerous cells

Diagnosis of Viral Diseases

Clinical picture, cell culture, viral antigen, and antibodies
Screening for immune response to virus

Transmission of Viruses

Respiratory transmission: Influenza A virus
Faecal-oral transmission: Enterovirus
Blood-borne transmission: Hepatitis B virus
Sexual transmission: HIV
Animal or insect vectors: Rabies virus and ARBO viruses

Respiratory Tract Infections

Adenoviruses: Adenoiditis, Pharyngitis, and Bronchopneumonitis
Cytomegalovirus: Interstitial pneumonitis
Varicella-zoster virus: Pneumonitis
Enteroviruses: Coxsackie B, ECHO
Rhinoviruses: Common cold
Coronaviruses: Common cold
Influenza viruses: Influenza (upper and lower respiratory tract infections)
Parainfluenza viruses: Parainfluenza (laryngitis, tracheitis)
Respiratory syncytial virus: Bronchopneumonitis

Gastrointestinal Infections

Norwalk-like viruses (caliciviruses): epidemic outbreaks of gastroenteritis, associated with consumption of contaminated foods and aerosol spread
Hepatitis A virus: Infective hepatitis, transmitted through contaminated foods, causing fever, anorexia, nausea, vomiting, jaundice, and dark urine
Poliovirus: causes poliomyelitis, three antigenically distinct types, transmitted through fecal-oral route and close personal contact

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Description

This quiz covers the basics of virology, including virus structure, transmission, diagnosis, and types of viral infections. Learn about the characteristics of viruses and how they affect the human body.