Virology Chapter: Viral Latency and Reactivation
40 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following is NOT a potential outcome of infection with a DNA virus?

  • Chronic infection leading to cell transformation and oncogenesis
  • Persistent infection characterized by viral replication without cell death and eventual resolution (correct)
  • Acute infection leading to cell death and clearance
  • Latency leading to reactivation and productive infection

During latency, why are viral transcripts made to inhibit viral replication?

  • To facilitate the reactivation of the virus and subsequent productive infection
  • To trigger an immune response that will clear the virus from the infected cell
  • To ensure the virus remains dormant by preventing the production of viral proteins (correct)
  • To decrease the likelihood of cell death and ensure the survival of the infected cell

What is the primary reason why CD8+ T cells are unable to recognize and eliminate infected cells during latency?

  • The viral genome is integrated into the host cell's DNA, making it undetectable to CD8+ T cells
  • Latency triggers a suppression of the immune system, rendering CD8+ T cells ineffective
  • The infected cells are protected by a viral protein coat that prevents CD8+ T cell recognition
  • The virus is not actively replicating, so there are no viral proteins present on the cell surface for CD8+ T cells to recognize (correct)

Why is latency considered a successful strategy for some viruses?

<p>It allows the virus to evade the host's immune system and establish a long-term infection (B)</p> Signup and view all the answers

Which of the following statements concerning reactivation of a latent viral infection is TRUE?

<p>Reactivation can occur frequently in immunocompromised individuals (C)</p> Signup and view all the answers

What is the main difference between acute and chronic viral infection?

<p>Acute infections are transient and resolve quickly, while chronic infections persist for a long period (A)</p> Signup and view all the answers

What is the primary mode of transmission for a virus that establishes latency?

<p>Transmission through infected bodily fluids (B)</p> Signup and view all the answers

What is the main reason why antiviral drugs are less effective during latency?

<p>Antiviral drugs can only target actively replicating viruses (B)</p> Signup and view all the answers

Which of the following viral characteristics is NOT directly associated with the establishment of latency?

<p>Ability to spread to other cells and cause rapid replication (C)</p> Signup and view all the answers

A patient presents with a rash that follows a single dermatome, along with acute pain and redness in the area. What is the most likely diagnosis?

<p>Herpetic Whitlow (D)</p> Signup and view all the answers

What is the most common cause of corneal blindness, excluding trauma?

<p>HSV-1 (D)</p> Signup and view all the answers

A pregnant woman with active genital herpes should undergo what procedure to minimize the risk of transmission to her newborn?

<p>Cesarean section (B)</p> Signup and view all the answers

Which of these conditions is NOT a secondary manifestation of HSV-1 and HSV-2 infections?

<p>Lymphadenopathy (D)</p> Signup and view all the answers

Acyclovir and its derivatives are used to treat which of the following viral infections?

<p>HSV-1, HSV-2, and VZV (B)</p> Signup and view all the answers

Which of the following statements correctly reflects the relationship between HSV-1 and HSV-2?

<p>HSV-1 and HSV-2 are distinct viruses with separate modes of transmission and distinct primary manifestations. (F)</p> Signup and view all the answers

What is the role of LATs mRNA during HSV and VZV recurrences?

<p>LATs mRNA inhibits the transcription of IE genes, thus suppressing a productive viral infection and preventing recurrence. (F)</p> Signup and view all the answers

What is the primary site of viral latency for both HSV-1 and HSV-2?

<p>Neurons (H)</p> Signup and view all the answers

Which of the following is NOT a characteristic of the human herpesviruses (HHVs) discussed in the context provided?

<p>Their infection results in only lytic infections, without latent phases. (B), The HHVs have a seasonal incidence based on climatic conditions. (J)</p> Signup and view all the answers

From the text, which statement best outlines the impact of a strong cellular immune response on herpes simplex virus (HSV) infections?

<p>A strong cellular immune response can reduce the frequency and severity of HSV recurrences but cannot eliminate the virus completely. (C), A strong cellular immune response can suppress recurrences but does not completely eliminate the virus from the body. (F)</p> Signup and view all the answers

What does the term "tegument" refer to in the context of herpesviruses, as outlined in the text?

<p>The space located between the envelope and the capsid of the virus. (F)</p> Signup and view all the answers

Which of the following statements is TRUE about the initial infection of HSV?

<p>The initial infection typically resolves within two weeks, but the virus remains latent in the infected cells. (A)</p> Signup and view all the answers

What is the primary clinical presentation of HSV-1 infection in children?

<p>Herpes labialis (B), Gingivostomatitis (F)</p> Signup and view all the answers

How does the transmission of VZV differ from other herpesviruses?

<p>VZV is spread through airborne transmission and direct contact, unlike other herpesviruses. (E)</p> Signup and view all the answers

Which of the following DNA viruses is classified as double-stranded?

<p>Adenovirus (A), Polyomavirus (B)</p> Signup and view all the answers

What type of transmission is commonly associated with herpesviruses?

<p>Direct contact with infected lesions (C)</p> Signup and view all the answers

Which of the following viruses is known for having a latency phase in its infection process?

<p>Hepatitis B virus (D)</p> Signup and view all the answers

Which DNA virus is associated with genital warts and can lead to cervical cancer?

<p>Papillomavirus (A)</p> Signup and view all the answers

Which of these DNA viruses is typically vaccine-preventable?

<p>Hepatitis B virus (A)</p> Signup and view all the answers

What is the characteristic feature of parvoviruses compared to other DNA viruses?

<p>They have a single-stranded genome (A)</p> Signup and view all the answers

What is a common clinical manifestation of infection by poxviruses?

<p>Skin lesions or rash (D)</p> Signup and view all the answers

Which of the following statements accurately describes the typical outcome of a primary polyomavirus infection in an immunocompetent individual?

<p>The virus is usually asymptomatic and establishes a latent infection in the kidneys. (A)</p> Signup and view all the answers

What is the most common mode of transmission for polyomaviruses?

<p>Exposure to contaminated water, stool, urine, or saliva. (D)</p> Signup and view all the answers

What is the primary cellular target of JC Virus (JCV) in the body?

<p>Monocyte-lineage cells and B cells (C)</p> Signup and view all the answers

Under what circumstances is reactivation of a latent polyomavirus infection most likely to occur?

<p>In individuals with a compromised immune system, such as those with AIDS. (A)</p> Signup and view all the answers

What is the primary clinical manifestation of a reactivated BK Virus (BKV) infection?

<p>Hemorrhagic cystitis, characterized by bloody urine. (B)</p> Signup and view all the answers

What is the most definitive diagnostic method for confirming a PML diagnosis?

<p>Histological examination of brain tissue for areas of demyelination and inclusions. (B)</p> Signup and view all the answers

What is the most effective approach to managing a case of PML?

<p>Reducing or eliminating immunosuppressive therapy. (B)</p> Signup and view all the answers

What is the primary reason for the high fatality rate associated with PML?

<p>The virus disrupts the myelin sheath, leading to demyelination and neurological dysfunction. (A)</p> Signup and view all the answers

Which of the following individuals is most likely to be at risk for developing PML?

<p>An AIDS patient with a severely compromised immune system. (D)</p> Signup and view all the answers

Which of the following options represent current strategies for preventing and controlling polyomavirus infections? (Choose all that apply)

<p>Maintaining good personal hygiene and sanitation practices. (A), Implementing strict infection control measures in healthcare settings. (C)</p> Signup and view all the answers

Flashcards

DNA virus classification

DNA viruses classified as either single-stranded or double-stranded, based on the structure of their genetic material.

Viral latency

A state where a virus remains dormant within a host's cells without causing immediate illness, but can reactivate later.

Herpesviruses

A group of viruses known for causing a variety of infections, including cold sores, chickenpox, and shingles.

Adenoviruses

Viruses that often cause respiratory infections, such as the common cold, but can also cause other illnesses.

Signup and view all the flashcards

Papillomaviruses

Viruses that can cause warts and some types of cancer, particularly cervical cancer.

Signup and view all the flashcards

Noroviruses

Viruses that are a common cause of gastroenteritis, a stomach flu.

Signup and view all the flashcards

Hepatitis B virus

Viruses known for causing hepatitis, leading to inflammation of the liver.

Signup and view all the flashcards

Episome latency

The virus can remain dormant within the host cell as an episome, a circular form of DNA that exists independently of the host cell's genome.

Signup and view all the flashcards

Integration into host DNA

The virus can also integrate its genome into the host cell's DNA, becoming a permanent part of the cell's genetic material.

Signup and view all the flashcards

Immune escape during latency

During latency, the immune system doesn't recognize the infected cell as being infected, allowing the virus to escape the host's defense mechanisms.

Signup and view all the flashcards

Minimal viral gene expression

In latency, only a minimal amount of viral genes are expressed, preventing the immune system from recognizing the infected cell.

Signup and view all the flashcards

Reactivation of Latent Infection

The virus can reactivate after an extended period of latency, leading to a productive infection with the virus replicating and potentially causing symptoms.

Signup and view all the flashcards

Factors influencing reactivation

Reactivation can occur due to various factors, such as weakened immune system, stress, or environmental triggers.

Signup and view all the flashcards

Clinical presentation of reactivation

Reactivation can cause illness or may be asymptomatic, but the infected individual can still be infectious.

Signup and view all the flashcards

Recurrent infections

Recurrent infections after reactivation tend to be less severe and easier to clear, thanks to the immune memory developed during the initial infection.

Signup and view all the flashcards

HSV-1 & HSV-2: What are they?

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are viruses that cause a variety of infections, including cold sores, genital herpes, and keratoconjunctivitis. They remain latent in the body and can reactivate later, leading to recurring symptoms.

Signup and view all the flashcards

What are the treatments for HSV-1 and HSV-2?

Acyclovir and its derivatives are antiviral medications used to treat HSV-1 and HSV-2 infections. They help manage symptoms and shorten the duration of outbreaks.

Signup and view all the flashcards

What are the potential complications of HSV-1?

In addition to cold sores, HSV-1 can also cause keratoconjunctivitis, an infection of the cornea that can lead to corneal scarring and blindness. It is the second most common cause of corneal blindness after trauma.

Signup and view all the flashcards

What is VZV?

Varicella-zoster virus (VZV) is the virus that causes chickenpox and shingles. It is a highly contagious virus that can cause a painful rash and other systemic symptoms.

Signup and view all the flashcards

How is VZV related to shingles?

After a primary chickenpox infection, the VZV remains latent in the body and can reactivate later to cause shingles. Shingles typically presents as a painful rash along a single dermatome, which is an area of skin innervated by a single spinal nerve root.

Signup and view all the flashcards

What is Polyomavirus?

A DNA virus that typically causes asymptomatic infections in people with healthy immune systems.

Signup and view all the flashcards

How are Polyomaviruses spread?

Polyomaviruses are spread through various bodily fluids, including saliva, urine, feces, or contaminated water. Inhalation is another common mode of transmission.

Signup and view all the flashcards

Where do Polyomaviruses target in the body?

Polyomaviruses have a tropism for tonsils and lymphocytes, and they typically remain latent in the kidneys.

Signup and view all the flashcards

What is the typical outcome of a Polyomavirus infection?

The most common outcome of Polyomavirus infection is a persistent and latent infection. However, reactivation can occur in immunocompromised individuals or during pregnancy.

Signup and view all the flashcards

Are Polyomavirus infections usually symptomatic?

The majority of Polyomavirus infections are asymptomatic, meaning people don't experience any symptoms.

Signup and view all the flashcards

What happens during the primary Polyomavirus infection?

The primary infection with Polyomavirus typically occurs in the kidneys and remains latent. It is usually asymptomatic.

Signup and view all the flashcards

When does Polyomavirus reactivation occur?

Polyomavirus can reactivate in individuals with weakened immune systems or during pregnancy, leading to replication in the CNS (central nervous system) and/or urinary tract.

Signup and view all the flashcards

What is Progressive Multifocal Leukoencephalopathy (PML)?

Progressive Multifocal Leukoencephalopathy (PML) is a subacute demyelinating disease caused by Polyomavirus JC reactivation. It mainly impacts individuals with AIDS.

Signup and view all the flashcards

What are common symptoms of PML?

Typical symptoms of PML include forgetfulness, difficulty speaking, vision problems, and problems with balance, all suggestive of brain lesions.

Signup and view all the flashcards

How are Polyomavirus infections diagnosed?

Diagnosis of Polyomavirus infections typically involves urine cytology tests searching for characteristic cells, imaging techniques like MRI or CT to detect lesions, and PCR testing to detect viral DNA in various bodily fluids.

Signup and view all the flashcards

Herpes Simplex Virus (HSV)

A type of herpesvirus known for causing oral herpes (cold sores) and genital herpes.

Signup and view all the flashcards

Latency

The period when a virus, like HSV, hides in the body without causing symptoms.

Signup and view all the flashcards

Reactivation

The period when a latent virus, like HSV, becomes active again, causing symptoms.

Signup and view all the flashcards

HSV-1

A specific type of HSV that causes oral herpes (cold sores).

Signup and view all the flashcards

HSV-2

A specific type of HSV that causes genital herpes.

Signup and view all the flashcards

Primary HSV Infection

The initial infection with HSV, typically characterized by sores and fever.

Signup and view all the flashcards

HSV Transmission to Sensory Ganglion

The process where HSV travels up the nerve to a sensory ganglion, where it can become latent.

Signup and view all the flashcards

Sensory Ganglion

The location where HSV can become latent, typically in the sensory ganglion.

Signup and view all the flashcards

Episomal Form

The form of HSV DNA that exists during latency, where the virus is not actively replicating.

Signup and view all the flashcards

Study Notes

Medically Important DNA Viruses

  •  Study content focuses on DNA viruses.
  •  Learning objectives include classifying DNA viruses by structure and genome, discussing the importance of latency in clinical disease, and describing the following viruses: herpesviruses, adenoviruses, papillomaviruses, polyomavirus, parvoviruses, hepatitis B virus, and poxviruses. Each description should include the source/transmission, infection timeline, disease associations/manifestations, and if vaccine-preventable.

Classification of DNA Viruses

  •  DNA viruses are categorized by their structure and genome, distinguishing between single-stranded and double-stranded forms.

Importance of Latency

  •  The presentation highlights the critical role of latency in clinical disease processes.

General Characteristics of DNA Viruses (Human)

  •  There are seven viral families of DNA viruses (–viridae) relevant to humans.
  •  Viral genomes can be linear or circular, partially circular, partially double-stranded, double-stranded, or single-stranded.
  •  Viral replication may occur in the nucleus or cytoplasm.
  •  Viruses utilize cellular or viral DNA or RNA polymerases to replicate their genomes and synthesize mRNA.

DNA Viruses & Their Characteristics

  •  The presentation provides detailed characteristics of various DNA viruses, including those with different envelopes and shapes: non-enveloped, linear, icosahedral; enveloped, linear, icosahedral; non-enveloped, circular, icosahedral; etc.
  •  Specific examples of viral families and types, such as Parvoviridae (Parvovirus B19), Adenoviridae (Adenovirus), Papillomaviridae (Human Papilloma Virus [HPV]), Polyomaviridae (JC Virus, BK Virus), Poxviridae (Molluscum contagiosum, Cowpox, Variola virus (smallpox), vaccinia virus, monkeypox), Hepadnaviridae (Hepatitis B virus), and Herpesviridae (Herpes Simplex Virus [HSV] 1, Herpes Simplex Virus [HSV] 2, Varicella-zoster virus [VZV], Epstein Barr Virus [EBV] and others)

Parvovirus B19

  •  Structure: non-enveloped, icosahedral, single-stranded DNA virus.
  •  Transmission: respiratory, direct contact with oral secretions.
  •  Tropism: erythroblasts.
  •  Outcome: cell lysis, drop in mature red blood cells [anemia].
  •  Geography: worldwide.
  •  Clinical presentation: involves a rash ("slapped-cheek" appearance), arthritis, and anemia.

Adenovirus

  •  Structure: non-enveloped, icosahedral, double-stranded DNA virus.
  •  Transmission: aerosols, fecal-oral, direct contact, auto-inoculation (eye).
  •  Tropism: mucosal epithelium of upper respiratory and GI tract.
  •  Outcome: lytic, persistent, and latent infections.
  •  Geography: worldwide.

Human Papillomavirus (HPV)

  •  Structure: non-enveloped, circular, icosahedral, double-stranded DNA virus.
  •  Transmission: direct contact, possibly contaminated fomites.
  •  Tropism: epithelial cells of skin, mucous membranes.
  •  Outcome: lytic, chronic, or transforming. - Causes warts, condylomas, papillomas. - Can lead to cervical, penile, or anal carcinomas.
  •  Geography: worldwide.

Polyomavirus

  •  Structure: non-enveloped, icosahedral, double-stranded DNA virus.
  •  Transmission: inhalation; fecal-oral; contact with contaminated water, stool, urine, or saliva.
  •  Tropism: tonsils, lymphocytes, kidneys [BK Virus], kidney, B cells, monocyte-lineage cells [JC Virus].
  •  Outcome: persistent, latent infection.
  •  Geography: worldwide.

Herpesviridae

  •  Structure Enveloped, linear DNA virus, icosahedral.
  •  Transmission: direct contact, bodily fluids, and potentially aerosolized.
  •  Tropism: varies
  •  Outcome: Lytic, latent, recurrent infections
  •  Causes: cold sores, genital herpes, chicken pox, shingles, mononucleosis, roseola, other related viral diseases.
  •  Geography: worldwide.

Poxviruses

  •  Structure: Complex DNA virus, enveloped.
  •  Transmission: direct contact, respiratory.
  •  Tropism: varies.
  •  Outcome: Lytic.
  •  Causes: smallpox, vaccinia, cowpox, monkeypox, molluscum contagiosum.

Hepadnaviridae

  •  Structure: Enveloped, DNA virus, partially circular, icosahedral.
  •  Transmission: blood and body fluids
  •  Tropism: hepatocytes.
  •  Outcome: acute and chronic liver infections.

Diagnosis, Treatment, Prevention and Control of DNA Viral Infections

  •  Specific to each viral types with considerations for supportive therapies, antiviral medications, and vaccinations, where available.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Medically Important DNA Viruses 2025 PDF

Description

Test your knowledge on viral latency and reactivation in this quiz. Explore how DNA viruses establish latency, the immune response to such infections, and the implications for antiviral treatments. Ideal for students studying virology and infectious diseases.

More Like This

Human Herpesviruses Quiz
13 questions

Human Herpesviruses Quiz

ReliableMesa avatar
ReliableMesa
Viral Biology Concepts
20 questions

Viral Biology Concepts

VeritableSparkle avatar
VeritableSparkle
Microbiology Chapter 6: Viral Multiplication
15 questions

Microbiology Chapter 6: Viral Multiplication

GoldNeon avatar
GoldNeon
Herpesvirus Replication and Characteristics
24 questions

Herpesvirus Replication and Characteristics

AccomplishedZeal1503 avatar
AccomplishedZeal1503
Use Quizgecko on...
Browser
Open
Browser
Browser