Herpes Zoster and Epstein-Barr Virus Quiz

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Questions and Answers

Which of the following correctly describes the clinical manifestation of herpes zoster in older patients?

It causes acute lesions that heal in days.

It typically resolves without any complications.

It results in acute respiratory complications.

It can lead to a chronic painful syndrome lasting months or years. (correct)

What is the primary treatment method for varicella-zoster virus infection in immunocompromised patients?

Broad-spectrum antibiotics

Drug therapy and VZIg (correct)

Topical antivirals

Acetaminophen for pain relief

What characterizes the microscopic features seen in a Tzank smear of herpes zoster?

Multinucleated giant cells and ground glass nuclear inclusions (correct)

Single-cell necrosis with no other findings

Presence of inflammatory lymphocytes only

Only polymorphonuclear leukocytes are observed

Which viral cell receptors does Epstein-Barr Virus (EBV) primarily target?

B lymphocytes and epithelial cells Signup and view all the answers

What proportion of the global population is estimated to be infected with Epstein-Barr Virus by adulthood?

90-95% Signup and view all the answers

What occurs during the secondary viremia of Varicella-Zoster Virus infection?

The virus spreads throughout the body and causes a rash. Signup and view all the answers

Which of the following clinical features distinguishes herpes zoster from other rashes?

Lesions on the scalp. Signup and view all the answers

What is a common complication of Varicella-Zoster Virus infection in adults?

Interstitial pneumonia. Signup and view all the answers

What is the primary method of transmission for Varicella-Zoster Virus?

Respiratory routes. Signup and view all the answers

Which antiviral strategy can be utilized against Varicella-Zoster Virus?

Antiviral drugs targeting thymidine kinase. Signup and view all the answers

How does cell-mediated immunity affect Varicella-Zoster Virus?

It helps control disease severity but can cause symptoms. Signup and view all the answers

Which of the following is NOT a type of cell primarily infected by Varicella-Zoster Virus?

Red blood cells. Signup and view all the answers

What characterizes the rash caused by Varicella-Zoster Virus during the varicella phase?

It appears as pustules which heal into crusts. Signup and view all the answers

What is a common characteristic of recurrent Herpes Simplex infections?

They are preceded by a prodrome of burning sensation. Signup and view all the answers

Which of the following statements about neonatal Herpes Simplex Virus infections is true?

Localized encephalitis carries a mortality rate of 14%. Signup and view all the answers

What is the recommended preventive measure for pregnant women with a history of Herpes Simplex Virus?

Undergo cesarean section to prevent transmission. Signup and view all the answers

Which form of Herpes Simplex Virus is commonly associated with cold sores?

HSV-1 Signup and view all the answers

Which clinical manifestation is unique to primary Herpes Simplex infections?

Painful but benign disease with clear vesicles. Signup and view all the answers

What is the most common viral cause of sporadic encephalitis?

Herpes Simplex Virus (HSV) Signup and view all the answers

Which statement regarding the pathology of the Varicella-Zoster Virus is correct?

It can cause both primary chickenpox and shingles. Signup and view all the answers

What is NOT a recommended management practice for Herpes Zoster infections?

Administration of a Herpes Simplex vaccine. Signup and view all the answers

Study Notes

Herpesviruses

Herpesviruses are DNA viruses characterized by their large, enveloped icosahedral capsids.
Herpesviruses have three subfamilies: Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae.
These subfamilies differ in genome structure, tissues tropism, cytopathologic effect, site of latent infection, and disease manifestation.

Herpesvirus Evolutionary Tree

Herpesviruses are grouped by their evolutionary relationships in an evolutionary tree.
The tree shows the relationships between various types of herpesviruses.
The distribution of herpes viruses into subfamilies, is alpha (α), beta (β), and gamma(γ)

Properties Distinguishing the Herpesviruses

Table 51-1 details the subfamily, virus type, primary target cell, site of latency, and means of spreading.
Alphaherpesvirinae viruses (e.g., Herpes simplex type 1 and 2) primarily infect mucoepithelial cells and establish latency in neurons; spread by close contact.
Gammaherpesvirinae viruses (e.g., Epstein-Barr virus) primarily infect B cells and other cells, and the site of latency is unclear; transmission occurs via saliva and close contact.
Betaherpesvirinae viruses (e.g., Cytomegalovirus) primarily infect monocytes, lymphocytes, and epithelial cells, and latency is found in various places; spread by close contact, transfusions, congenital transmission, and tissue transplantation.

Unique Features of Herpesviruses

Herpesviruses contain double-stranded DNA genomes within large, enveloped icosadeltahedral capsids.
They encode many proteins regulating host cell functions such as shut-off of messenger RNA, DNA and protein synthesis.
Viral DNA replication and assembly occur in the nucleus.
Release is by exocytosis and cell lysis.
Herpesviruses cause lytic, persistent, latent, and (in the case of Epstein-Barr virus) immortalizing infections.

Herpes Simplex Virus (HSV)

HSV has two types: HSV-1 and HSV-2.
HSV-1 and HSV-2 share similar antigenic determinants (cross-reactive antigens), tissue tropism and symptoms.
Genomes are ~152 kbp.
There is ~50% DNA sequence homology between HSV-1 and HSV-2.

Replication of Herpes Simplex Virus

HSV infects most human cells, causing lytic infections in fibroblasts and epithelial cells and latent infection in neurons.
Receptor = heparan sulfate
Coreceptor= nectin-1
Envelope contains 10 glycoproteins (gB, gC, gD, gE, gH,..)
Proteins are glycosylated, enzymes associated with capsids and teguments enclosed in an envelope.

Pathogenesis of Herpes Simplex Virus: Primary Infection

HSV-1 and HSV-2 share similar pathogenesis during primary infection: replicating in mucoepithelial cells and causing local diseases.
HSV-1 is associated with infections above the waist.
HSV-2 is associated with infections below the waist.
Pathogenesis results from cytolysis, caused by inhibition of host cell molecule synthesis, chromatin degradation, cytoskeletal disruption, and cell senescence.

Varicella-Zoster Virus (VZV)

VZV causes chickenpox (varicella) and upon recurrence, causes herpes zoster or shingles.
Different from HSV in that VZV spreads initially through respiratory transmission, then replicates locally, causing viremia, and infecting skin over entire body.
Shares common characteristics with HSV, including latent infections, and cell-mediated immunity preventing serious disease.

Varicella-Zoster Virus (VZV): Pathology

VZV replicates in the lung and is a major source of contamination.
Secondary viremia occurs after 2 weeks, spreading virus and causing a rash of vesicular-pustular lesions which develop in successive crops.
Immunocompromised individuals are at higher risk of serious disease.

Epstein-Barr Virus (EBV)

B lymphocytes and epithelial cells are primary targets of EBV.
EBV discovered through electron microscopy observations in biopsy specimens from lymphomas (e.g., African Burkitt lymphoma).
EBV is associated with infectious mononucleosis discovered through serological testing.
EBV is found worldwide, and most people contract the infection by adulthood.

Epstein-Barr Virus (EBV): Replication and Structure

EBV genome encodes for 70 proteins.
Non-productive infection, the cells contain plasmidelike EBV genomes replication only occurring during cell division.
Productive infection, EBV expresses selective genes for immortalization.
Latent Membrane Proteins (LMPs)
Early Antigen (EA)
Viral Capsid Antigen (VCA)
Membrane Antigens (MA)

Epstein-Barr Virus (EBV): Pathogenesis

EBV infection of B cells establishes lifelong infection; causing infectious monucleosis.
Productive infection of B cells and epithelial cells spreads virus in saliva to others.
EBV proteins activates B-cell growth and prevents apoptosis, leading to non-specific IgM production.
Continued B-cell proliferation may lead to lymphoma development
EBV infection may lead to infectious mononucleosis, lymphoma, and other diseases.

Human Cytomegalovirus (HCMV)

HCMV is the most common viral cause of congenital defects.
HCMV exhibits mild or asymptomatic infection in most cases.

Human Cytomegalovirus (HCMV): Pathogenesis

HCMV is acquired through bodily secretions (blood, tissues, secretions).
Replication and shedding occur without symptoms for some people while others may experience mild disease manifestations.
Reactivation occurs due to immunosuppression.
Cell-mediated immunity is required for disease resolution.

Human Cytomegalovirus (HCMV): Clinical Syndromes

Congenital infection can result in small size, thrombocytopenia, rash, CMV inclusion disease, mental retardation and/or unilateral or bilateral hearing loss.
Perinatal infection (during or after delivery) usually shows no symptoms.

Human Herpesvirus 6 (HHV-6)

Two closely related viruses: HHV-6A and HHV-6B.
Usually acquired in infancy or early childhood.
Causes roseola in children.

Human Herpesvirus-7 (HHV-7)

HHV-7 is not known to cause disease in humans.

Human Herpesvirus-8 (HHV-8) or Kaposi's Sarcoma-Associated Herpesvirus (KSHV)

HHV-8 is present in Kaposi's sarcoma, predominantly in male homosexuals and HIV-1-positive men.
B cells, endothelial and epithelial cells are primary targets.
Predominantly a latent infection; most likely sexually transmitted.

Treatment of Herpes Simplex Virus

Antiviral drugs are available to treat HSV infections.

Treatment of Varicella-Zoster Virus

Antiviral drugs are available to treat VZV infections.

Treatment of Epstein-Barr Virus

No treatment or vaccine is available.

Treatment of Cytomegalovirus

Antiviral drugs: acyclovir, ganciclovir, foscarnet.

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Description

Test your knowledge on the clinical manifestations and treatments related to herpes zoster, as well as the features and impact of Epstein-Barr Virus. This quiz covers important aspects of virology and clinical presentation in older and immunocompromised patients. Challenge your understanding of viral infections and their global prevalence.