DNA Viruses and Adenoviridae Overview
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Questions and Answers

Which family of DNA viruses is classified as nonenveloped and is known to replicate in the nucleus?

  • Poxviridae
  • Hepadnaviridae
  • Herpesviridae
  • Adenoviridae (correct)

    • What is the replication site for double-stranded DNA viruses?

  • Cytoplasm
  • Ribosomes
  • Nucleus (correct)
  • Cell membrane

    • Which of the following DNA virus families is known for being single-stranded?

  • Papillomaviridae
  • Parvoviridae (correct)
  • Polyomaviridae
  • Adenoviridae

    • Which virus infection is likely to remain asymptomatic for months after initial infection?

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

    Which characteristic is true for Poxviridae among DNA viruses?

    <p>It replicates in the cytoplasm.</p> Signup and view all the answers

    What disease does CAdV-1 primarily cause in dogs?

    <p>Infectious canine hepatitis</p> Signup and view all the answers

    Which adenovirus type is associated with kennel cough?

    <p>CAdV-2</p> Signup and view all the answers

    What is a common characteristic of adenoviruses regarding immunity?

    <p>They induce effective and long-lasting immunity</p> Signup and view all the answers

    How do maternal antibodies help infants regarding adenovirus infections?

    <p>They protect infants against severe respiratory infections</p> Signup and view all the answers

    What role do neutralizing antibodies play in resistance to clinical disease from adenoviruses?

    <p>They are directly related to resistance to clinical disease</p> Signup and view all the answers

    In which age group is over 50% of infants found to have neutralizing antibodies against adenoviruses?

    <p>6-11 months old</p> Signup and view all the answers

    Which types of animals can also be affected by adenoviruses?

    <p>Horses, cattle, pigs, sheep, and goats</p> Signup and view all the answers

    Which of the following statements about adenovirus immunity in normal, healthy adults is correct?

    <p>They have antibodies to several types of adenoviruses</p> Signup and view all the answers

    What is the primary focus of the late phase of adenovirus infection?

    <p>Production of structural proteins</p> Signup and view all the answers

    What happens as a result of virally induced cell lysis in adenovirus infections?

    <p>Virus particles are released</p> Signup and view all the answers

    How many virus particles can be produced per infected adenovirus cell?

    <p>100,000</p> Signup and view all the answers

    Which of the following is true about the assembly process of adenoviruses?

    <p>About 80% of hexon capsomeres and 90% of viral DNA are not used</p> Signup and view all the answers

    What type of cells are particularly affected by adenoviruses in cultures?

    <p>Epithelial cells</p> Signup and view all the answers

    What morphological changes do adenoviruses cause in infected cells?

    <p>Rounded, enlarged cells forming grape-like clusters</p> Signup and view all the answers

    Which statement about adenoviruses and cancer is accurate?

    <p>Adenoviruses are not thought to be significant in human cancer</p> Signup and view all the answers

    What characteristic is commonly seen in cells infected with adenoviruses in culture?

    <p>Presence of rounded intranuclear inclusions containing DNA</p> Signup and view all the answers

    What is a common symptom of pharyngoconjunctival fever caused by adenoviruses?

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

    Which types of adenoviruses primarily cause epidemic keratoconjunctivitis?

    <p>Types 8 and 19</p> Signup and view all the answers

    What is a likely outcome for patients with epidemic keratoconjunctivitis?

    <p>Subepithelial opacities in the cornea</p> Signup and view all the answers

    Which adenovirus serotypes are associated with infantile gastroenteritis?

    <p>Types 40 and 41</p> Signup and view all the answers

    How do adenoviruses primarily spread in eye infections?

    <p>Hand-to-eye transfer</p> Signup and view all the answers

    Which group of patients is at higher risk for severe adenovirus infections?

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

    In which type of transplant patients is adenovirus hepatitis a concern?

    <p>Liver transplants</p> Signup and view all the answers

    What is the typical duration for the resolution of epidemic keratoconjunctivitis?

    <p>1-2 weeks</p> Signup and view all the answers

    What is the primary mechanism for the synthesis of viral mRNA in parvoviruses?

    <p>Cellular RNA polymerase using double-stranded DNA</p> Signup and view all the answers

    Which transmission route is NOT associated with parvoviruses?

    <p>Transmission through contaminated food</p> Signup and view all the answers

    What is a common clinical manifestation of erythema infectiosum in children?

    <p>Slapped cheek rash</p> Signup and view all the answers

    What outcome may result from parvovirus infection in patients with hemolytic disorders?

    <p>Aplastic crisis (anemia)</p> Signup and view all the answers

    What is the effect of parvovirus on viral replication?

    <p>Results in cell death</p> Signup and view all the answers

    What characteristic symptom can persist for a long duration in adults infected with parvovirus?

    <p>Polyarthralgia-arthritis</p> Signup and view all the answers

    Which of the following statements about patients with fifth disease is true?

    <p>They are probably no longer infectious by the time of onset of rash.</p> Signup and view all the answers

    Which population is most commonly affected by erythrema infectiosum?

    <p>Children of early school age</p> Signup and view all the answers

    What is the effect of parvovirus on a healthy individual's immune system?

    <p>Results in mild, transient symptoms</p> Signup and view all the answers

    Which of the following is not a typical feature of parvovirus infections?

    <p>Severe gastrointestinal disease</p> Signup and view all the answers

    Study Notes

    DNA Viruses

    • All DNA viruses replicate in the nucleus except for Poxviridae
    • Poxviridae replicate in the cytoplasm
    • All DNA viruses are double stranded except for Parvoviridae
    • Poxviridae is a complex virus, all other viruses are icosahedral

    Adenoviridae

    • First isolated in 1953
    • Many infections are subclinical
    • Virus can persist in the host for months
    • Early genes control host and viral transcription and DNA replication, late genes are for virion structure
    • Viral infectious cycle takes about 24 hours
    • Produces about 100,000 virus particles per cell
    • Assembly process is inefficient
    • Adenoviruses are cytopathic for human cells
    • They do not induce syncytia or multinucleated giant cells

    Adenovirus Infections

    • Marked rounding, enlargement and aggregation of affected cells into grape-like clusters
    • Can morphologically transform cells in culture but are not thought to be important in human cancer
    • Cells infected with oncogenic adenoviruses contain rounded intranuclear inclusions containing DNA

    Adenovirus Eye Infections

    • Transmitted in several ways but hand to eye transfer is most common
    • Types 3, 7, and 21 are associated with pharyngoconjunctival fever
    • Symptoms are similar to acute febrile pharyngitis but conjunctivitis is also present
    • Occurs in outbreaks
    • Duration of the illness is 1 to 2 weeks
    • Most people recover completely without lasting sequelae

    Adenovirus Eye Infections Cont.

    • Types 8, 19, and 37 are associated with epidemic keratoconjunctivitis
    • Occurs mainly in adults and is highly contagious
    • Resolves in 2 weeks but may leave sub epithelial opacities for up to 2 years

    Adenovirus Gastrointestinal Disease

    • Many adenoviruses replicate in intestinal cells and are present in the stool without being associated with GIT disease
    • Types 40 and 41 are associated with 5-15% of viral gastroenteritis cases in young children

    Adenovirus Other Infections

    • Transplant patients may suffer adenovirus infections, especially in the gastrointestinal tract
    • Liver transplant patients may develop adenovirus hepatitis in the allograft
    • Heart transplant patients who develop myocardial adenovirus infections are at increased risk of graft loss
    • Immunocompromised patients suffer adenovirus infections, especially in the gastrointestinal tract
    • Types 11 and 21 may cause acute hemorrhagic cystitis in children, especially boys
    • Adenoviruses are commonly found in the urine of immunocompromised patients

    Adenovirus Canine Infections

    • A form of adenovirus that is highly infectious in dogs causing an acute liver infection
    • CAdV-1 causes infectious canine hepatitis, respiratory and eye infections
    • CAdV-2 is a potential cause of kennel cough
    • Core vaccines for dogs include attenuated live CAdV-2, which produces immunity to CAdV-1 and CAdV-2

    Adenovirus Other Animal Infections

    • Adenoviruses are known to cause respiratory infections in horses, cattle, pigs, sheep, and goats

    Adenovirus Immunity

    • Most healthy adults have antibodies to several adenovirus types
    • Maternal antibodies protect infants from severe adenovirus respiratory infections
    • Resistance to clinical disease is directly related to the presence of circulating neutralizing antibodies, which probably persist for life

    Parvoviridae Replication

    • The viral mRNA is synthesized by cellular RNA polymerase from the double-stranded DNA intermediate
    • Newly synthesized single-stranded DNA is converted to double-stranded DNA and serves as a template for transcription or replication
    • Progeny virions are assembled in the nucleus.
    • They are released by cell lysis
    • There are two capsid proteins
    • Viral replication results in cell death

    Parvoviridae Transmission

    • The respiratory route
    • Parenterally by blood transfusions
    • Vertically from mother to fetus

    Parvoviridae Transmission Cont.

    • There is no evidence of virus excretion in feces or urine
    • Transmission of B19 from patient with aplastic crisis to members of the hospital staff has been documented
    • Patients with aplastic crisis are likely to be infectious during the course of their illness
    • Patients with fifth disease are probably no longer infectious by the time of onset of the rash

    Parvoviridae Pathogenesis

    • Erythema infectiosum (fifth disease), a common childhood exanthem
    • Aplastic crisis (anemia) in patients with hemolytic disorders
    • Fetal death
    • Chronic anemia in immunocompromised individuals
    • Polyarthralgia-arthritis syndrome in adults

    Parvoviridae Erythema Infectiosum

    • Most common in children of early school age
    • Illness is biphasic: First and Second
    • Both sporadic cases and epidemics have been described
    • Symptoms mimic rheumatoid arthritis and the arthropathy may persist for weeks, months, or years

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    Nonenveloped DNA Viruses (Parvoviridae, Adenoviridae, Papovaviridae) PDF

    Description

    Explore the fascinating world of DNA viruses, focusing on the unique characteristics of Adenoviridae. Learn about their replication processes, infectious cycles, and effects on human cells. This quiz covers essential concepts relevant to virology and the biology of pathogens.

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