Jawetz Chapter 31
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Jawetz Chapter 31

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Questions and Answers

What is the main target for human B19 parvovirus in the erythroid lineage?

  • White blood cells
  • Platelets
  • Immature cells (correct)
  • Mature red blood cells

    • Which subfamily of Parvoviridae infects vertebrates?

  • Parvovirinae (correct)
  • Adenoviridae
  • Densovirinae
  • Papillomaviridae

    • What type of nucleic acid do parvoviruses possess?

  • Circular double-stranded DNA
  • Linear single-stranded DNA (correct)
  • Single-stranded RNA
  • Double-stranded RNA

    • What is the size range of parvovirus virions?

    <p>18–26 nm</p> Signup and view all the answers

    What environment condition is noted for human B19 parvovirus?

    <p>Environmentally stable</p> Signup and view all the answers

    What type of infections can occur in immunocompromised patients with B19 parvovirus?

    <p>Chronic anemia</p> Signup and view all the answers

    Which protein is considered the major one in parvoviruses?

    <p>VP2</p> Signup and view all the answers

    Where does the replication of parvoviruses primarily take place?

    <p>In the nucleus</p> Signup and view all the answers

    What can result from viral replication of B19 parvovirus in the host?

    <p>Cell death and interruption of red blood cell production</p> Signup and view all the answers

    What is the most sensitive assay for detecting parvovirus?

    <p>Polymerase chain reaction (PCR)</p> Signup and view all the answers

    What is the initial treatment for Fifth disease?

    <p>Symptomatic treatment</p> Signup and view all the answers

    In which patient group can commercial immunoglobulin preparations be beneficial?

    <p>Immunocompromised patients</p> Signup and view all the answers

    What type of samples can bocavirus DNA be detected in?

    <p>Serum, saliva, stool samples, and respiratory specimens</p> Signup and view all the answers

    What indicates recent infection with parvovirus B19?

    <p>Detection of B19 IgM antibody</p> Signup and view all the answers

    What type of disease does human bocavirus primarily cause?

    <p>Acute respiratory infection</p> Signup and view all the answers

    Which of the following treatments is available for human bocavirus infections?

    <p>No specific treatment</p> Signup and view all the answers

    What is observed about viral loads during acute infections of parvovirus B19?

    <p>They can reach approximately $10^{11}$ genome copies/mL</p> Signup and view all the answers

    What is a potential future development regarding human parvovirus?

    <p>A vaccine for humans</p> Signup and view all the answers

    What symptom might severe anemia due to parvovirus infection require?

    <p>Blood transfusion therapy</p> Signup and view all the answers

    Which condition is associated with human parvovirus B19 infection?

    <p>Erythema infectiosum</p> Signup and view all the answers

    Which cell receptor is utilized by human parvovirus B19 for entry?

    <p>Blood group antigen P</p> Signup and view all the answers

    What is a true statement about human parvovirus B19 infection?

    <p>It typically does not lead to any significant human disease.</p> Signup and view all the answers

    Which characteristic of human parvovirus B19 replication is correct?

    <p>It stimulates resting cells to proliferate.</p> Signup and view all the answers

    Which statement about treatment for parvovirus B19 is correct?

    <p>No specific antiviral treatment is generally required for parvovirus B19.</p> Signup and view all the answers

    Which infection can lead to hydrops fetalis when caused by parvovirus B19?

    <p>Fifth disease</p> Signup and view all the answers

    What is the most common manifestation of human parvovirus B19 infection in children?

    <p>Erythema infectiosum</p> Signup and view all the answers

    In which conditions is transient aplastic crisis most likely to occur?

    <p>Chronic hemolytic anemia</p> Signup and view all the answers

    Which symptom is typically associated with erythema infectiosum in children?

    <p>Rash with a 'slapped cheek' appearance</p> Signup and view all the answers

    What is one of the clinical findings in adult cases of parvovirus B19 infection?

    <p>Joint involvement</p> Signup and view all the answers

    What occurs as a result of transient aplastic crisis in patients with chronic hemolytic anemia?

    <p>Abrupt cessation of red blood cell synthesis</p> Signup and view all the answers

    What is a key feature of the anemia experienced by patients during a transient aplastic crisis?

    <p>It results from sudden cessation of erythropoiesis</p> Signup and view all the answers

    What type of infection occurs in healthy individuals during a transient aplastic crisis?

    <p>No detectable anemia</p> Signup and view all the answers

    What age group is most commonly affected by erythema infectiosum?

    <p>School-age children</p> Signup and view all the answers

    Which of the following is NOT typically a symptom of parvovirus B19 infection?

    <p>Coughing fits</p> Signup and view all the answers

    What could complicate chronic hemolytic anemia during a parvovirus B19 infection?

    <p>Transient aplastic crisis</p> Signup and view all the answers

    Which hygiene practice is recommended to prevent the spread of B19 virus?

    <p>Not sharing drinks</p> Signup and view all the answers

    What does the presence of B19 IgG antibody indicate?

    <p>Long-term immunity</p> Signup and view all the answers

    What can be detected to diagnose chronic B19 infections in immunodeficient patients?

    <p>B19 viral DNA</p> Signup and view all the answers

    Which condition is most commonly associated with B19 infection during early pregnancy?

    <p>Hydrops fetalis</p> Signup and view all the answers

    What percentage of adults are estimated to be seropositive for B19?

    <p>60%</p> Signup and view all the answers

    What is the primary method used for laboratory diagnosis of B19 infection?

    <p>Serology and molecular assays</p> Signup and view all the answers

    What age group is most commonly affected by parvovirus infection?

    <p>Children aged 5 to 19 years</p> Signup and view all the answers

    Which of the following is a result of B19 infection?

    <p>Transient aplastic crisis</p> Signup and view all the answers

    What type of cells does the human B19 virus primarily target?

    <p>Erythroid progenitor cells</p> Signup and view all the answers

    What is the nature of human B19 and bocavirus with regards to laboratory culture?

    <p>Difficult to grow</p> Signup and view all the answers

    Study Notes

    Parvovirus Overview

    • Parvoviruses are small viruses belonging to the family Parvoviridae, which has two subfamilies: Parvovirinae (infect vertebrates) and Densovirinae (infect invertebrates).
    • Human B19 parvovirus targets immature erythroid cells, with major replication sites in adult marrow, specific blood cells, and fetal liver.
    • Viral replication leads to cell death, disrupting red blood cell production.

    Important Properties of Parvoviruses

    • Virion structure: Icosahedral, measuring 18–26 nm in diameter, composed of 32 capsomeres.
    • Composition: Consists of 80% protein and 20% DNA.
    • Genome characteristics: Single-stranded, linear DNA of 5.6 kb, molecular weight between 1.5–2.0 million.
    • Proteins: Major protein (VP2) and minor protein (VP1) are present.
    • Lacks an envelope and replicates in the nucleus, relying on dividing host cells.

    Clinical Manifestations

    • Erythema Infectiosum (Fifth Disease): Most common manifestation, characterized by a fever and a "slapped cheek" rash, primarily affecting children aged 5-19.
    • Transient Aplastic Crisis: An abrupt cessation of red blood cell synthesis in patients with chronic hemolytic anemias, leading to worsening anemia.
    • Symptoms in adults may include joint pain due to immune complex deposition, particularly in hands and knees.

    Laboratory Diagnosis

    • Viral DNA is detected using polymerase chain reaction (PCR) and serological tests.
    • High viral loads can reach approximately 10^11 genome copies/mL during acute infections.
    • Serologic assays reveal IgM antibodies indicating recent infection; IgG antibodies persist for years.

    Treatment and Prevention

    • Symptomatic treatment is the primary approach; severe anemia may require blood transfusion.
    • No antiviral drugs or vaccines are available for human parvovirus B19, though hygienic practices can help prevent transmission.
    • Animal parvovirus vaccines exist, and serologic assays are performed for exposure determination.

    Epidemiology

    • B19 parvovirus infections are widespread throughout the year across all age groups, with outbreaks frequently occurring in schools.
    • Transmission is mainly via respiratory droplets; up to 60% of adults and 90% of elderly individuals are seropositive.
    • Human bocavirus is associated with respiratory illnesses and gastroenteritis, but causation remains unproven.

    Conclusion

    • Human B19 parvovirus poses significant health risks, particularly in immune-compromised individuals and during pregnancy. Continuous research is essential to develop vaccines and treatment options.

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    Related Documents

    Jawetz Chapter 31: Parvoviruses PDF

    Description

    Explore the essential characteristics of parvoviruses, including their structure, genome, and clinical manifestations. Learn about human B19 parvovirus and its impact on red blood cell production. This quiz covers the fundamental aspects of these small but significant viruses.

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