Microbiology trans - DNA Viruses
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Questions and Answers

What is the recommended dosage of Acyclovir for immunosuppressed patients with zoster?

  • 800 mg five times daily (correct)
  • 1 g by mouth three times daily
  • 500 mg three times daily
  • 400 mg twice daily

    • When should antiviral therapy for zoster be initiated?

  • As soon as the rash appears
  • Within 5-7 days after symptoms
  • Within 24-48 hours of symptoms (correct)
  • Within 72 hours of symptoms

    • Which antiviral medication is taken three times daily for 7 days?

  • Ganciclovir
  • Famciclovir (correct)
  • Acyclovir
  • Valacyclovir

    • What is the duration of therapy for Valacyclovir when prescribed for zoster?

    <p>5-7 days</p> Signup and view all the answers

    What is another name for Epstein-Barr Virus?

    <p>HHV-4</p> Signup and view all the answers

    How is Epstein-Barr Virus primarily spread?

    <p>Bodily fluids, primarily saliva</p> Signup and view all the answers

    What is the primary method used for identifying adenoviruses in infected cells?

    <p>Immunofluorescence test using anti hexon antibody</p> Signup and view all the answers

    Which sample type is NOT mentioned for adenovirus detection?

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

    Which diagnostic method can identify any member of the adenovirus group?

    <p>Complement fixation test</p> Signup and view all the answers

    What type of virus structure does adenovirus have?

    <p>Naked virus with icosahedral nucleocapsid</p> Signup and view all the answers

    Which of the following methods can be used to directly detect viral antigens?

    <p>Staining of basal epithelial cells</p> Signup and view all the answers

    What is the significance of a four-fold or greater rise in complement fixing antibody titer?

    <p>Signifies recent infection</p> Signup and view all the answers

    What kind of DNA do adenoviruses possess?

    <p>Double-stranded linear DNA</p> Signup and view all the answers

    How is adenovirus primarily transmitted?

    <p>Direct contact with infected individuals and contaminated surfaces</p> Signup and view all the answers

    Which HPV types are responsible for the majority of cervical cancers?

    <p>Types 16 and 18</p> Signup and view all the answers

    What is the primary feature of papillomaviruses in relation to their infection?

    <p>They exhibit great tissue and cell specificity.</p> Signup and view all the answers

    Which virus family is classified as non-enveloped DNA viruses?

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

    What is the replication location for parvoviruses?

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

    Which agent cannot inactivate viruses?

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

    What must happen for parvoviruses to use the host's DNA replication machinery?

    <p>The host must enter the S-phase.</p> Signup and view all the answers

    Which of the following viruses is known as Cytomegalovirus?

    <p>HHV-5</p> Signup and view all the answers

    Which family of viruses is implicated in causing diseases similar to human herpesvirus?

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

    What mechanism do parvoviruses utilize to enter host cells?

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

    Which of the following viruses does NOT belong to the Herpesviruses group?

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

    Which phase of the host cell cycle is critical for parvovirus replication?

    <p>S phase</p> Signup and view all the answers

    What is a major clinical characteristic of varicella?

    <p>Generalized vesicular eruption of the skin and mucous membranes</p> Signup and view all the answers

    What is the most common source of herpes simplex virus infection in newborns?

    <p>The mother</p> Signup and view all the answers

    What distinguishes varicella from herpes zoster?

    <p>Varicella features successive crops of vesicles</p> Signup and view all the answers

    What is the greatest susceptibility for primary herpes infection in newborns?

    <p>Between 6 months to 2 years</p> Signup and view all the answers

    Which group is at higher risk for severe complications of varicella?

    <p>Adults and immunocompromised individuals</p> Signup and view all the answers

    What is a common complication of varicella in neonates, adults, and immunocompromised patients?

    <p>Varicella pneumonia</p> Signup and view all the answers

    How do newborns typically acquire herpes simplex virus?

    <p>In utero or during the birth process</p> Signup and view all the answers

    What is a common route of infection for a newborn during delivery?

    <p>Contact with herpetic lesions in the birth canal</p> Signup and view all the answers

    Which statement about neonatal varicella is true?

    <p>It can occur from maternal infection before or after birth.</p> Signup and view all the answers

    What is the mortality rate for varicella in normal children?

    <p>Very low, with complications being rare</p> Signup and view all the answers

    What is one potential benefit of antiviral drugs such as Acyclovir?

    <p>It shortens healing time and reduces recurrences</p> Signup and view all the answers

    What is a characteristic of how a newborn's immune response to HSV works?

    <p>Maternal antibodies are present but do not prevent infection</p> Signup and view all the answers

    What is a rare but possible life-threatening complication of varicella?

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

    What does a cesarean section aim to prevent in mothers with genital herpes?

    <p>Transmission of the virus to the baby</p> Signup and view all the answers

    How are lesions of varicella and herpes zoster characterized?

    <p>Both result in vesicular lesions</p> Signup and view all the answers

    What type of pattern does varicella infection follow?

    <p>A centrifugal pattern</p> Signup and view all the answers

    What effect do maternal antibodies have on subsequent herpes infections in the newborn?

    <p>They may modify subsequent disease but cannot prevent reactivation</p> Signup and view all the answers

    What often follows varicella infection in survivors?

    <p>Permanent sequelae</p> Signup and view all the answers

    What is the primary role of antiviral therapy in patients with genital herpes?

    <p>To suppress symptoms and reduce risk of transmission</p> Signup and view all the answers

    Why is it significant for mothers with herpes to understand asymptomatic shedding?

    <p>It is a common source of transmission even when there are no visible symptoms</p> Signup and view all the answers

    Study Notes

    Overview of DNA Viruses

    • DNA viruses categorized into two groups: non-enveloped and enveloped.
    • Non-enveloped DNA viruses include Parvoviridae, Adenoviruses, and Papovaviridae.
    • Enveloped DNA viruses include Herpesviruses, Poxviruses, and Hepatitis B Virus.

    Parvoviridae

    • Parvoviruses depend on host cellular functions for replication.
    • Viral DNA replication occurs within the nucleus after endocytosis.
    • Cannot induce host cells into S-phase; await the host cell cycle to enter.

    Adenoviruses

    • Detected in respiratory samples, conjunctiva, blood, stool, and urine; early sample collection enhances detection.
    • Diagnosis can employ immunofluorescence tests, hemagglutination inhibition tests, and polymerase chain reaction (PCR) assays.
    • Hexon protein is the primary structural protein of Adenovirus.
    • Transmission occurs via direct contact, sexual contact, or contaminated surfaces (fomites).

    Human Papillomavirus (HPV)

    • Causes hyperplastic epithelial lesions across diverse host tissues.
    • Infection is tissue-specific, primarily affecting skin and mucous membranes.
    • Types 16 and 18 are linked to cervical carcinoma, contributing to over 70% of cases.

    Herpes Simplex Virus (HSV)

    • Neonatal herpes can originate from infected mothers during birth or after birth.
    • Newborns are especially vulnerable; maternal antibodies offer temporary protection but do not prevent infection.
    • Antiviral treatments (Acyclovir, Valacyclovir) suppress symptoms, aid healing, and reduce recurrences.

    Varicella Zoster Virus (VZV)

    • Causes Chickenpox (Varicella), characterized by a generalized vesicular skin eruption.
    • Complications are rare in children; more severe in adults and immunocompromised patients.
    • Diagnosis and treatment regimens involve antiviral medications like Acyclovir, Famciclovir, and Valacyclovir administered promptly within 24-48 hours of symptom onset.

    Epstein-Barr Virus (EBV)

    • Known as Human herpesvirus-4, primarily transmitted through saliva.
    • In healthy individuals, most infected cells are effectively eliminated, reducing virus spread.

    Clinical Notes

    • For genital herpes, antiviral therapy can reduce asymptomatic shedding and transmission risk.
    • Varicella pneumonia is a significant complication in neonates, adults, and immunocompromised individuals.

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    DNA Viruses Lecture Notes - Microbiology

    Description

    This quiz covers the topic of DNA viruses discussed in the Microbiology lecture held on September 13, 2024. It includes details on inactivation methods such as formalin and 𝛃-propiolactone. Test your understanding of the characteristics and classifications of non-enveloped DNA viruses.

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