Herpes and VZV Overview Quiz
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Questions and Answers

Which characteristic is shared by both HSV-1 and HSV-2?

  • 50% DNA homology. (correct)
  • Primarily causing disease below the waist.
  • Latent infections of fibroblast cells.
  • Predominantly lytic infections of neurons.

How is HSV-1 typically transmitted?

  • Through oral contact or saliva-contaminated items. (correct)
  • During vaginal delivery from mother to infant.
  • Through sexual contact.
  • Via autoinoculation.

Which of the following is a typical manifestation of a herpes simplex virus lesion?

  • A clear vesicle on an erythematous base. (correct)
  • A dark, hard nodule with a clear base.
  • A deep, scarred tissue with a pustular border.
  • A white plaque on an erythematous base.

What type of cells does HSV-1 and HSV-2 typically infect at the entry site, causing lysis?

<p>Fibroblast and epithelial cells. (A)</p> Signup and view all the answers

Which condition is most often associated with HSV-2 transmission during birth?

<p>Neonatal infection with dissemination to multiple organs. (D)</p> Signup and view all the answers

Which of the following diagnostic methods is most useful for identifying a primary HSV infection?

<p>Serology. (B)</p> Signup and view all the answers

What is the primary mechanism of action of nucleoside analog drugs like acyclovir in treating HSV infection?

<p>Inhibiting viral DNA synthesis. (A)</p> Signup and view all the answers

Where does HSV-1 typically establish latency after initial infection?

<p>Trigeminal ganglia. (B)</p> Signup and view all the answers

What is the primary method by which Varicella-Zoster Virus (VZV) reactivates?

<p>Through anterograde travel towards nerve endings from the sensory ganglia (B)</p> Signup and view all the answers

Which of the following best describes the effectiveness of nucleoside analogs against VZV?

<p>They are effective at reducing fever and skin lesions if treatment starts within 3 days of infection onset, before lesions. (C)</p> Signup and view all the answers

Which clinical manifestation is associated with the reactivation of Varicella-Zoster Virus (VZV)?

<p>Vesicular rash along a specific dermatome. (C)</p> Signup and view all the answers

How is Varicella-Zoster Virus (VZV) diagnosed from skin lesions?

<p>Genome detection in clinical specimens. (D)</p> Signup and view all the answers

What is a common characteristic of the rash associated with VZV reactivation (shingles)?

<p>It is localized to a single dermatome and often painful. (B)</p> Signup and view all the answers

What specific characteristic of Varicella-Zoster Virus (VZV) is not addressed by common antiviral drugs?

<p>The virus in its latent state. (A)</p> Signup and view all the answers

What is a key mechanism of VZV that leads to the formation of a dermatomal rash during reactivation?

<p>Formation of multinucleated giant cells (polykaryocytes) in skin cells. (C)</p> Signup and view all the answers

Which of the following HPV vaccine types targets the most HPV types?

<p>9-valent vaccine (Gardasil 9) (C)</p> Signup and view all the answers

What is the primary function of the L1 protein in HPV vaccines?

<p>To form empty shells that resemble HPV viruses, triggering an immune response (C)</p> Signup and view all the answers

Which of the following is NOT a way that VZV virus can be detected?

<p>Through blood culture. (B)</p> Signup and view all the answers

Which of the following is NOT a recommended screening test for cervical cancer?

<p>Blood test for HPV antibodies (A)</p> Signup and view all the answers

What is the main characteristic of a koilocyte cell as observed in a Pap smear?

<p>An enlarged cell with a clear halo around a shrunken nucleus (C)</p> Signup and view all the answers

Which of the following treatment methods is NOT typically used for the removal of HPV-related warts or precancerous lesions?

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

What is the typical seroprevalence rate of Cytomegalovirus (CMV) in adults?

<p>50-90% (D)</p> Signup and view all the answers

Which of the following is NOT a target cell for CMV infection?

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

In which cells does CMV typically remain latent?

<p>Myeloid stem cells (A)</p> Signup and view all the answers

What are the potential severe disease outcomes of primary CMV infection or reactivation in immunocompromised individuals?

<p>Interstitial pneumonia, gastroenteritis, and retinitis. (C)</p> Signup and view all the answers

Which of these is NOT a mode of horizontal transmission of CMV?

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

Which of the following is a route of vertical transmission of CMV?

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

Which of the following is NOT a typical sign of congenital CMV infection?

<p>Elevated blood pressure (D)</p> Signup and view all the answers

When is the risk for birth defects highest in infants with congenital CMV?

<p>When mothers had primary CMV infections during their pregnancies. (C)</p> Signup and view all the answers

Which of the following is NOT a common organ system affected by Cytomegalovirus (CMV) in immunocompromised individuals?

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

Why is viral isolation in fibroblast cell cultures not a suitable method for rapid CMV diagnosis?

<p>The cytopathic effect develops slowly, requiring weeks (B)</p> Signup and view all the answers

Which diagnostic method is most useful for detecting congenital CMV infection?

<p>Molecular diagnosis using PCR (D)</p> Signup and view all the answers

Why is serology not always dependable for diagnosing CMV infection in immunocompromised patients?

<p>IgM levels can rise even during CMV reactivation, not just primary infection (B)</p> Signup and view all the answers

Which of the following antiviral drugs is NOT specifically mentioned for the treatment of CMV infections?

<p>Acyclovir (C)</p> Signup and view all the answers

Which of the following is a hallmark feature of Epstein-Barr Virus (EBV) infection?

<p>Seropositivity is high in adults, with intermittent shedding (A)</p> Signup and view all the answers

What is the primary route of transmission for Epstein-Barr Virus (EBV)?

<p>Saliva (oral route) (A)</p> Signup and view all the answers

What is a key mechanism by which EBV establishes infection in B cells?

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

What is the primary target cell for HHV-8?

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

Which condition is NOT associated with HHV-8 infection?

<p>Cervical cancer (B)</p> Signup and view all the answers

What type of papillomavirus is primarily responsible for cervical cancer?

<p>High-risk genital HPVs (C)</p> Signup and view all the answers

Which statement about HPV-related lesions screening is true?

<p>Pre-cancerous lesions can be treated to prevent cancer. (C)</p> Signup and view all the answers

What is a characteristic of genital HPV infections?

<p>Usually transient and clear within 3 years (B)</p> Signup and view all the answers

Which HPV types are primarily associated with respiratory papillomatosis?

<p>HPV 6 and 11 (B)</p> Signup and view all the answers

What role do the E6 and E7 proteins play in HPV infections?

<p>They upregulate growth by targeting p53 and pRB pathways. (C)</p> Signup and view all the answers

Which of the following is a method of definitive HPV diagnosis?

<p>PCR and real-time PCR analysis (A)</p> Signup and view all the answers

What are the symptoms of condyloma acuminata due to HPV infections?

<p>Numerous warts in genital and anal areas (D)</p> Signup and view all the answers

What is the primary method to diagnose cutaneous HPV infections?

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

Flashcards

HSV-1 and HSV-2

Two types of herpesviruses that share common features like DNA structure, antigens, and target cells, but cause different symptoms and transmission routes.

HSV-1

Usually spread through oral contact or saliva, causing sores around the mouth and lips (cold sores).

HSV-2

Primarily transmitted sexually, and can cause genital sores and blisters.

Herpetic Lesion

A typical herpes symptom that begins as a clear blister on a red base and progresses to a pus-filled sore, then crusts over before healing.

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Neonatal Herpes

Infection in newborns that can occur during childbirth or through the placenta, causing severe disease.

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Viral Isolation

A laboratory test using cultured cells to identify the presence of herpes virus.

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Genome Detection

A laboratory technique used to detect the herpes virus's genetic material from samples.

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Nucleoside Analogs

Antiviral medications, like acyclovir, used to treat herpes infections by preventing the virus from replicating.

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What is Cytomegalovirus (CMV)?

A common human virus that infects a majority of people by age five. It remains inactive in the body but can reactivate in individuals with weakened immune systems.

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Which cells does CMV prefer to infect?

CMV primarily targets cells like fibroblasts, epithelial cells, and endothelial cells, suggesting it has a wide range of potential target tissues.

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Where does the virus remain latent?

The virus can remain dormant in cells like myeloid stem cells, monocytes, and lymphocytes, meaning it can stay hidden in the body for long periods.

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What are the health risks of CMV reactivation?

CMV can cause serious complications in immune-compromised individuals, leading to infections like pneumonia, gastroenteritis, and retinitis.

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How is CMV transmitted to newborns?

CMV is a major cause of congenital infections, meaning it can be passed from a mother to her unborn child.

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What is horizontal transmission of CMV?

Horizontal transmission refers to CMV spreading between individuals through contact with bodily fluids like saliva, tears, or urine.

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How can CMV spread through organ transplantation?

CMV can also spread through organ transplantation from an infected donor to a recipient.

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What is one way CMV can spread through breastfeeding?

CMV can be transmitted from a mother to her child through breast milk.

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Antiviral drugs for VZV

Antiviral drugs that specifically target VZV are effective in shortening the duration of clinical symptoms and suppressing viral reactivation. However, they cannot eliminate the latent virus.

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VZV reactivation

VZV establishes a latent infection in sensory ganglia. When immune responses weaken, the virus reactivates and travels along nerve fibers causing a dermatomal vesicular rash.

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VZV reactivation mechanism

During the reactivation phase, the virus replicates in skin cells, forming polykaryocytes and causing the characteristic dermatomal rash.

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Clinical manifestations of VZV

VZV infection typically manifests as chickenpox (primary infection) or shingles (reactivation). These are distinct clinical manifestations caused by the same virus.

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Shingles (herpes zoster)

The hallmark of shingles is a painful vesicular rash confined to a single dermatome, which could potentially lead to post-herpetic neuralgia.

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Diagnosis of VZV

The diagnosis of VZV can be confirmed through viral isolation from lesions, genome detection in clinical specimens, or by serological testing.

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Treatment of VZV

Acyclovir, valacyclovir, and famciclovir are nucleoside analogs used in the treatment of active VZV infection. These drugs effectively reduce viral dissemination and often improve symptoms.

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VZV vaccines

VZV vaccines containing live, attenuated virus derived from the Oka strain are available for both primary prevention and boosting immunity.

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Cytomegalovirus (CMV)

Human cytomegalovirus (HCMV) is a common virus that can infect a wide range of tissues and organs, particularly in people with weakened immune systems.

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Diagnosing CMV Infection

CMV infection can be diagnosed through various methods, including viral cultivation (isolating the virus in a lab setting), molecular detection (using PCR to detect the viral genome), and serological testing (detecting antibodies against the virus).

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Treating CMV Infections

Ganciclovir, valganciclovir, cidofovir, and foscarnet are the main antiviral drugs used to treat CMV infections in immunocompromised patients.

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Epstein-Barr Virus (EBV)

Epstein-Barr virus (EBV) is a widespread virus that typically causes mononucleosis (infectious mononucleosis) in children and adolescents.

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EBV Target Cells

EBV can infect both epithelial cells (lining the mouth and throat) and B lymphocytes (white blood cells involved in immunity).

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Lytic and Latent EBV infections

EBV infections can be either lytic, where the virus actively replicates and causes cell death, or latent, where the virus remains dormant within the host.

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EBV Transmission

EBV is highly transmissible through saliva, making it easily spread through close contact, such as kissing.

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EBV Ubiquity and Shedding

Most adults have been exposed to EBV and carry it in their bodies, often shedding the virus in their saliva even when asymptomatic.

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Pap test

A type of cervical cancer screening test that involves examining cells from the cervix under a microscope to detect abnormal cells.

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Liquid-based cytology (LBC)

A type of cervical cancer screening test that uses a swab to collect cells from the cervix and then uses special liquid to preserve the cells for analysis.

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Visual Inspection with Acetic Acid (VIA)

A type of cervical cancer screening test that involves applying acetic acid (vinegar) to the cervix and looking for abnormal changes in the cervical tissue.

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Virus-like Particles (VLPs)

Virus-like particles (VLPs) are molecules that resemble viruses but do not contain viral genetic material. They are used in HPV vaccines to stimulate the immune system without causing infection.

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Quadrivalent HPV vaccine

A type of HPV vaccine that protects against HPV types 6, 11, 16, and 18, which are responsible for most cervical cancers and genital warts.

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Papillomaviruses (HPVs)

A family of viruses with double-stranded DNA genomes, known for causing warts and some cancers. The virus infects epithelial cells (skin and mucous membranes).

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HPV E6 and E7 Proteins

Proteins E6 and E7, produced by HPV, interfere with normal cell regulation, leading to uncontrolled growth of infected cells. They specifically target tumor suppressor proteins p53 and pRB which help control cell division.

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HPV Tissue Tropism

HPV can infect specific tissues based on their type.

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HPV Entry Mechanism

The entry of HPV into the basal cell layer of the skin often occurs through microscopic breaks or injuries, making the skin vulnerable to infection.

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HPV Persistence and Cervical Cancer

Most cases of HPV infection clear up within 3 years. However, persistent infections with high-risk HPV types significantly increase the risk of cervical cancer.

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Cutaneous HPVs and Warts

Benign growths on the skin caused by HPV infection, commonly known as warts. These growths result from increased cell growth and thickening of the skin layers.

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Epidermodysplasia Verruciformis (EV)

A rare condition characterized by the development of flat warts, which can progress to skin cancer. It's more likely to occur in people with a weakened immune system.

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Condyloma Acuminata (Genital Warts)

Genital warts commonly caused by HPV types 6 and 11, often referred to as condyloma acuminata. Characteristically, they can be found in the anal and genital regions.

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Respiratory Papillomatosis

Infections in the upper respiratory tract caused by HPV that can lead to respiratory papillomatosis, affecting the larynx, oral cavity, etc.

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Cervical Cancer Screening

This involves screening for precancerous lesions in the cervix, providing a window to treat abnormalities before they progress to cancer.

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Study Notes

Herpesviridae

  • Genome: linear double-stranded DNA
  • Icosahedral capsid with 162 capsomers, surrounded by an amorphous tegument
  • Spherical to pleomorphic envelope (150-200 nm in diameter)

Herpesviridae Subfamilies and Viruses

  • Alphaherpesvirinae:
    • HHV-1 (Herpes simplex type 1): mucoepithelial cells and neurons; spread via close contact (STD)
    • HHV-2 (Herpes simplex type 2): mucoepithelial cells and neurons; spread via close contact (STD)
    • HHV-3 (Varicella-zoster virus): mucoepithelial and T cells and neurons; spread via respiratory and close contact
  • Betaherpesvirinae:
    • HHV-5 (Cytomegalovirus): monocytes, granulocytes, lymphocytes, and epithelial cells; myeloid stem cell; spread via close contact (STD), transfusions, tissue transplant, and congenital
    • HHV-6: lymphocytes and T cells; spread via saliva
    • HHV-7 : like HHV-6, spread via saliva
  • Gammaherpesvirinae:
    • HHV-4 (Epstein-Barr virus): B cells and epithelial cells; spread via saliva (kissing disease)
    • HHV-8 (Kaposi's sarcoma-associated virus): lymphocytes and other cells; spread via saliva (possibly blood exposure)

Herpesvirus Replication

  • Attachment to host receptors mediates endocytosis
  • Fusion with plasma membrane releases nucleocapsid and tegument proteins into cytoplasm
  • Capsid transported to nuclear pore; viral DNA released into nucleus
  • Transcription/translation of immediate early genes (regulate gene transcription)
  • Replication of parental genome via rolling circle mechanism
  • Transcription/translation of late mRNAs (structural proteins)
  • Assembly in nuclear factories; budding through modified nuclear membrane
  • Release at plasma membrane (lytic replication)

Latent Replication

  • Viral DNA takes circular (episomal) structure
  • Generates latency-associated transcripts (LATs) instead of translating into proteins; inhibits important immediate early genes.

Herpes Simplex Virus (HSV) Type 1 and 2

  • HSV-1 and HSV-2 share characteristics (50% DNA homology)
  • HSV-1 typically spreads via oral contact or saliva-contaminated items, while HSV-2 is primarily spread through sexual contact or from an infected mother to infant at birth.
  • Neonatal HSV infection is often severe and potentially fatal.

Diagnosis and Therapy of HSV Infection

  • Diagnosis: Viral isolation from lesions, detection of viral genome (vesicle, tissue), serology (limited use).
  • Therapy: Nucleoside analogs (acyclovir, valacyclovir, famciclovir) inhibit viral DNA synthesis; shorten symptoms; doesn't affect latent virus

Varicella-Zoster Virus (VZV)

  • Primary infection (chickenpox) associated with mild febrile illness and generalized vesicular rash
  • VZV establishes a latent infection within sensory ganglia
  • Reactivation (shingles) causes vesicular rash along the entire dermatome, very painful post-herpetic neuralgia

Cytomegalovirus (CMV)

  • Ubiquitous; prevalent in children and adults (10-15% of children before age 5, 50-90% seroprevalence in adults).
  • Horizontal transmission through organ transplantation; contact with bodily secretions (saliva, tears, urine, semen, stool, vaginal/cervical secretions)
  • Vertical transmission through transplacental transmission, breastfeeding (maternal milk or colostrum).
  • Severe disease can result from primary infection or reactivation in immunocompromised hosts; can cause interstitial pneumonia, gastroenteritis, retinitis, organ transplant rejection, death.
  • CMV is a leading cause of congenital disease: microcephaly, intracerebral calcification, jaundice, hepatosplenomegaly, rash, vision or hearing loss, and mental retardation
  • In immunocompromised subjects, CMV can affect almost every organ (liver, lungs, central nervous system, gastrointestinal tract, kidneys, and eyes)

Epstein-Barr Virus (EBV)

  • Ubiquitous (80-90% seropositive adults)
  • Primarily spread through saliva.
  • Infections of epithelial cells of the oropharynx and nasopharynx; B-cells.
  • EBV can cause lytic infections of epithelial cells and latent infections or immortalization of B cells.
  • Acute infection can cause infectious mononucleosis (kissing disease).
  • Symptoms: Pharyngitis, swollen lymph nodes, enlarged spleen, exudative pharyngitis, high fever, malaise.
  • Associated with different cancers (endemic Burkitt lymphoma, Hodgkin disease, nasopharyngeal carcinoma, B-cell lymphomas).
  • Diagnosis is usually serological (Paul-Bunnel test, EBV-specific serologic tests)

Other Human Herpesviruses, HHV-6, HHV-7

  • HHV-6 (HHV-6A and HHV-6B) cause exanthem subitum (roseola) in young children (ages 6-24 months)
  • Rapid onset of high fever, followed by rash on the trunk and face.
  • Can reactivate in transplant patients, associated with MS and chronic fatigue syndrome

Other Human Herpesvirus, HHV-8

  • Member of the X-Herpesvirinae
  • Associated with Kaposi's sarcoma (KS), primary effusion lymphoma (a rare type of B-cell lymphoma, and multicentric Castleman disease).
  • B cells are the primary targets, but limited number of endothelial, monocyte, and epithelial cells are also affected.
  • More prevalent in some geographic areas (Italy, Greece, Africa) and those with HIV/AIDS, likely spread sexually or through blood exposure.

Papillomaviridae

  • Genome: double-stranded DNA, circular

  • Icosahedral capsid (50-55 nm)

  • Nonenveloped virus

  • 100 genotypes, classified by tissue tropism

  • Cutaneous HPVs cause warts (on skin).

  • Mucosal HPVs cause papillomas and condylomas (on mucous membranes)

  • Some types cause benign tumors, others cause carcinomas (e.g., cervical cancer)

  • E6 and E7 (proteins) promote unregulated growth.

  • The basal cell layer is a portal of entry via breaks in the skin.

  • Cutaneous syndromes: warts, epidermodysplasia verruciformis (EV)

  • Mucosal syndromes: papillomatosis, condyloma acuminata.

  • HPV causes six types of cancer, including cervical, vulvar, vaginal, oropharyngeal, anal and penile.

  • The infection is typically transient, but long-term high-risk HPV persistence is the most important predictor of cervical cancer.

  • HPV testing, visual inspection (VIA), and conventional Pap test (cytology) are important methods of screening for HPV-related lesions.

HPV Infection Treatment

  • Removal of warts and precancerous lesions (e.g., with salicylic acid, liquid nitrogen, laser or surgical removal)
  • Immune modifiers (e.g., interferon, imiquimod) boost the immune system.
  • HPV vaccines are prepared using virus-like particles (VLPs)
  • Three available vaccines: quadrivalent (Gardasil), 9-valent (Gardasil 9), bivalent (Cervarix).
  • Vaccination is initially recommended at age 11 or 12 for both boys and girls.
  • Continued cervical cancer screening is recommended.

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Herpesviruses: Types, Replication, and Diseases PDF

Description

Test your knowledge on herpes simplex viruses (HSV-1 and HSV-2) and Varicella-Zoster Virus (VZV) with this quiz. Covering transmission methods, symptoms, diagnostics, and treatment mechanisms, this quiz will help reinforce key concepts about these common viruses. Perfect for students studying virology or infectious diseases.

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