Introduction to Virology
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Questions and Answers

What does the emergence of the Omicron variant emphasize regarding vaccination?

  • Fully vaccinated individuals cannot spread the virus.
  • Vaccination is only necessary for older adults.
  • Vaccination and boosters are of increased importance. (correct)
  • Vaccination provides no protection against severe illness.

    • Which of the following factors is NOT associated with an increased risk of severe disease?

  • Chronic obstructive pulmonary disease
  • Older age
  • Active smoking habits (correct)
  • Malignancy

    • What are some laboratory markers indicative of severe disease?

  • Normal lactate levels
  • Decreased ferritin levels
  • Increased neutrophilia and lymphopenia (correct)
  • Low D-dimer levels

    • Which statement about the effectiveness of FDA-approved vaccines is accurate?

    <p>Vaccines significantly reduce the risk of severe illness, hospitalization, and death.</p> Signup and view all the answers

    Which preventive measure helps reduce the transmission of COVID-19?

    <p>Frequent hand-washing</p> Signup and view all the answers

    What distinguishes viruses from living organisms?

    <p>They have no cells and require a host cell for reproduction.</p> Signup and view all the answers

    Which component of a virus provides protection for its genetic material?

    <p>Capsid</p> Signup and view all the answers

    Which type of virus typically contains single-stranded RNA?

    <p>RNA viruses</p> Signup and view all the answers

    What occurs during a viral infection in a host cell?

    <p>The virus uses the host's cellular machinery to replicate.</p> Signup and view all the answers

    How can viruses be transmitted from one host to another?

    <p>By inhaling airborne droplets, among other methods.</p> Signup and view all the answers

    What is a common symptom of a viral illness?

    <p>Cell and tissue damage</p> Signup and view all the answers

    What type of viruses contain double-stranded DNA?

    <p>dsDNA viruses</p> Signup and view all the answers

    Which of the following is NOT a method of viral transmission?

    <p>Exclusion from the human body</p> Signup and view all the answers

    What are potential complications of upper respiratory tract infections?

    <p>Otitis media and sinusitis</p> Signup and view all the answers

    During which seasons is the incidence of rhinovirus infections highest?

    <p>Spring and fall</p> Signup and view all the answers

    Which of the following influenza types causes human disease?

    <p>Type B</p> Signup and view all the answers

    What is the primary mechanism through which influenza can escape immune recognition?

    <p>Antigenic drift</p> Signup and view all the answers

    What characterizes antigenic shift in influenza viruses?

    <p>Reassortment of genetic material from different subtypes</p> Signup and view all the answers

    Which group of individuals is at higher risk for severe infection from RSV?

    <p>Older adults and individuals with a weak immune system</p> Signup and view all the answers

    What is the common transmission method for influenza viruses?

    <p>Droplets from coughing and sneezing</p> Signup and view all the answers

    Which symptoms are typically associated with seasonal influenza compared to a common cold?

    <p>Body aches and severe fatigue</p> Signup and view all the answers

    What is the primary binding target for the SARS-CoV-2 virus to enter host cells?

    <p>Angiotensin-converting enzyme 2 (ACE 2)</p> Signup and view all the answers

    What makes the Delta variant of SARS-CoV-2 particularly concerning?

    <p>It spreads more easily and may cause more severe illness.</p> Signup and view all the answers

    Which condition can both rhinovirus and respiratory syncytial virus (RSV) cause?

    <p>Lower respiratory infections</p> Signup and view all the answers

    Which statement regarding vaccines and SARS-CoV-2 variants is true?

    <p>Vaccines help prevent severe illness, even with variants.</p> Signup and view all the answers

    What is currently unclear about the Omicron variant?

    <p>The severity of illness and death associated with it.</p> Signup and view all the answers

    What is one component of the viral envelope of SARS-CoV-2?

    <p>Spike (S) glycoprotein</p> Signup and view all the answers

    What was a significant consequence of the COVID-19 pandemic in 2020?

    <p>Non-essential travel was significantly reduced.</p> Signup and view all the answers

    How closely related is SARS-CoV-2 to the bat coronavirus RaTG13?

    <p>Approximately 96.2% similar</p> Signup and view all the answers

    Study Notes

    Introduction to Virology

    • Viruses are the smallest microbes.
    • They lack the characteristics of living things, except for the ability to replicate.
    • Viruses are neither prokaryotes nor eukaryotes.

    Viral Structure

    • Viruses are made up of a core of genetic material (DNA or RNA) surrounded by a protein capsid.
    • Sometimes, the capsid is surrounded by an additional spikey envelope.
    • Viruses have proteins that help them bind to and enter host cells

    Viral Replication

    • Viruses make copies of themselves to regenerate.
    • They acquire energy from their host cells.
    • Viruses infect cells by inserting their genetic material into them.

    Are Viruses Alive?

    • Viruses are not considered alive because they have no cells and require a host cell to replicate.
    • They use the host cell's mechanisms to reproduce.

    Viral Infection

    • A viral infection is the proliferation of a harmful virus inside the body.
    • Viruses need a host cell to replicate.
    • Viruses introduce their genetic material into host cells to produce more virus particles.

    Active Viral Infection

    • During an active viral infection, a virus makes many copies, causing the host cell to burst and release the new virus particles.
    • The new virus particles can then infect other cells.

    Symptoms of Viral Illness

    • Symptoms of a viral illness arise from cell damage, tissue destruction, and the immune response.

    Classification of Viruses

    • Viruses are classified based on their nucleic acid (DNA or RNA).
    • DNA viruses usually have double-stranded DNA (dsDNA), occasionally single-stranded DNA (ssDNA).
    • RNA viruses typically have single-stranded RNA (ssRNA), sometimes double-stranded RNA (dsRNA).

    Viral Transmission

    • Transmission methods include: touch, droplets, airborne particles, contaminated food/water, contaminated needles, sexual contact, and insect vectors.

    Respiratory Viral Infections

    • Examples include Rhinovirus (common cold), influenza viruses, RSV
    • Rhinovirus is responsible for most common colds.
    • Influenza viruses are more severe than the common cold, including body aches and fatigue.

    Seasonal Influenza

    • More than 200,000 people in the US are hospitalized annually due to flu complications.
    • Flu symptoms are more severe than colds.
    • Influenza viruses belong to the Orthomyxoviridae family.
    • Influenza viruses are classified based on nucleoproteins into types A, B and C; only A and B cause human disease.

    Seasonal Influenza Variations (Delta, Omicron)

    • Delta (B.1.617.2): Spreads easily, may be more severe, vaccines are effective, and treatments are available.
    • Omicron (B.1.1.529): May spread easily, current severity is unclear, vaccines are effective but some antibody treatments may not be as effective.
    • Fully vaccinated people can still spread the virus if infected.

    Risk factors of Severe COVID-19

    • Underlying conditions like older age, cardiovascular disease, chronic obstructive pulmonary disease, diabetes, and malignancy.
    • Clinical presentations such as high fever, dyspnea, higher qSOFA score, and altered mental status.

    COVID-19 Diagnosis

    • Laboratory markers: Neutrophilia/lymphopenia, raised lactate dehydrogenase, raised C-reactive protein, raised ferritin, raised IL-6, raised ACE2, and D-dimer >1 µg/mL.
    • Radiologic studies: Chest X-ray, Chest CT scan, and PCR.

    Prevention of Viral Infections

    • Frequent handwashing, social distancing, covering nose/mouth when coughing/sneezing, avoiding contact with infected individuals, disinfecting surfaces.

    Respiratory Syncytial Virus (RSV)

    • RSV can cause upper and lower respiratory infections, and symptoms mimic the common cold.

    SARS-COV-2 (COVID-19)

    • SARS-CoV-2 is a respiratory coronavirus.
    • It caused a global pandemic in 2020.
    • The virus is similar to SARS-CoV-1 and bat coronaviruses.
    • The viral envelope contains spike, envelope, and membrane proteins.
    • The virus binds to a host cell receptor via its spike protein.
    • The S1 subunit of the S protein binds to ACE2 in the host cell.
    • Symptoms of COVID-19 include cough, fever, shortness of breath, and pneumonia.

    Discussed Topics

    • General characteristics of viruses
    • Viral structure
    • Viral replication
    • Viruses according to nucleic acid (DNA & RNA)
    • Respiratory viral infections (Rhinovirus, Influenza, RSV)
    • SARS viruses (COVID-19)

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    Description

    Explore the fascinating world of viruses, the smallest microbes that challenge our understanding of life. This quiz covers viral structure, replication, and the ongoing debate about whether viruses are alive. Test your knowledge on their unique characteristics and the impact they have on living organisms.

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