Herpesviruses Chapter Overview

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Questions and Answers

What is the most common cause of congenital infection?

Acyclovir infection

Cytomegalovirus (CMV) (correct)

Epstein-Barr virus (EBV)

Infectious mononucleosis

What does the presence of IgM type antibodies to the viral capsid antigen indicate?

No infection present

Current infection (correct)

Past infection

Vaccination status

Which treatment shows promise for EBV-related lymphoproliferative disease?

Cytomegalovirus vaccine

Antibiotic therapy

Adoptive transfer of EBV-reactive T cells (correct)

Acyclovir

What effect does Acyclovir have on EBV shedding?

Reduces EBV shedding from the oropharynx Signup and view all the answers

What type of serologic tests require interpretation for EBV antibodies?

Serologic tests Signup and view all the answers

What is one symptom Acyclovir does NOT affect in patients with infectious mononucleosis?

Fever reduction Signup and view all the answers

Which of the following statements is true about cytomegalovirus (CMV)?

CMV can lead to severe abnormalities in congenital infections. Signup and view all the answers

What is NOT an effect of Acyclovir on EBV-associated lymphomas?

It enhances treatment efficacy. Signup and view all the answers

What is the significance of heterophile antibodies in infectious mononucleosis?

They agglutinate sheep cells. Signup and view all the answers

What is the commonality of cytomegalovirus (CMV) infections?

Common during childhood and adolescence Signup and view all the answers

What is the primary consequence of immunosuppression in patients regarding EBV?

Reactivation of latent EBV infection Signup and view all the answers

What is the classic syndrome associated with primary EBV infection in adolescents and young adults?

Infectious mononucleosis Signup and view all the answers

What type of lesions may develop on the tongue in AIDS patients due to EBV?

Oral hairy leukoplakia Signup and view all the answers

Which condition is least commonly associated with EBV?

Chronic fatigue syndrome Signup and view all the answers

Which finding indicates reactivation of EBV latent infections?

Increased levels of virus in saliva Signup and view all the answers

What percentage of transplant patients may develop an EBV-associated lymphoproliferative disorder?

1% to 10% Signup and view all the answers

What is the common outcome after an incubation period of 30-50 days due to EBV primary infection?

Headache, fever, malaise, fatigue, and sore throat Signup and view all the answers

What viral genome is commonly detected in malignant Reed-Sternberg cells?

EBV Signup and view all the answers

What type of malignancies are generally associated with EBV in the central nervous system?

Non-Hodgkin lymphomas Signup and view all the answers

What is a common characteristic of most primary EBV infections in children?

Asymptomatic presentation Signup and view all the answers

What is the role of VP16 in the viral replication process?

It activates initial viral gene expression. Signup and view all the answers

What is the typical incubation period for the described condition?

4–8 weeks Signup and view all the answers

What type of cells do herpesviruses typically infect, resulting in cell death?

Cells productively infected Signup and view all the answers

Which symptom is associated with hepatic dysfunction?

Lymphocytosis Signup and view all the answers

How does the length of the replication cycle vary among herpesviruses?

It varies widely from 18 to over 70 hours. Signup and view all the answers

Which group of herpesviruses is characterized by a long growth cycle and cytomegalic cytopathology?

Beta subfamily Signup and view all the answers

Which body fluid presents positive results for the described condition?

Throat swab Signup and view all the answers

Which herpesvirus is commonly associated with chickenpox?

Varicella-zoster virus Signup and view all the answers

What are the clinical findings associated with the disease?

Petechiae Signup and view all the answers

Which of the following is NOT a listed variable in the immunologic section?

White blood cell count Signup and view all the answers

What happens to normal cellular DNA and protein synthesis once viral replication begins?

It virtually stops. Signup and view all the answers

What condition could be a consequence of the described disease?

CNS damage Signup and view all the answers

In which part of the body do the alpha herpesviruses typically establish latency?

Neurons Signup and view all the answers

What biological properties define gamma herpesviruses?

Variable lymphoproliferative behavior Signup and view all the answers

Which of the following is NOT an example of a beta herpesvirus?

Herpes simplex virus type 2 Signup and view all the answers

Which of the following viruses is associated with lymphoid tissue infections?

Kaposi sarcoma-associated herpesvirus Signup and view all the answers

What is a key characteristic of herpesviruses?

They establish lifelong persistent infections in hosts. Signup and view all the answers

What is the size of an enveloped herpesvirus?

150–200 nm Signup and view all the answers

Which of the following herpesviruses shows the highest sequence homology?

HSV-1 and HSV-2 Signup and view all the answers

What type of genome do herpesviruses possess?

Double-stranded DNA Signup and view all the answers

How do the base compositions of herpesvirus DNAs vary?

From 31% to 75% (G + C) Signup and view all the answers

What effect might reactivation of herpesvirus infections have?

They can lead to serious health complications. Signup and view all the answers

What aids in the epidemiologic tracing of herpesviruses?

Restriction endonuclease treatment producing different cleavage patterns. Signup and view all the answers

How many human herpesviruses are commonly recognized?

Eight Signup and view all the answers

Which characteristic is unique to herpesvirus DNAs?

They have terminal and internal repeated sequences. Signup and view all the answers

Study Notes

Overview of Herpesviruses

Herpesviruses include significant human viral pathogens, presenting a broad spectrum of diseases.
They establish lifelong persistent infections and can reactivate periodically, particularly in the elderly and immunocompromised individuals.

Virus Structure and Genome

Enveloped virions measure 150–200 nm; non-enveloped (naked) form is 125 nm.
The double-stranded DNA genome ranges from 125–240 kbp and is linear with terminal and internal repeated sequences.
Herpesvirus genomes show varying base compositions (31% to 75% G + C) and limited homology among different viruses.

Classification of Human Herpesviruses

Alpha Subfamily: Short, cytolytic growth cycle affecting neurons (e.g., HSV-1, HSV-2, Varicella-zoster virus).
Beta Subfamily: Long, cytomegalic growth involving glands and kidneys (e.g., Cytomegalovirus, HHV-6, HHV-7).
Gamma Subfamily: Variable, lymphoproliferative growth affecting lymphoid tissue (e.g., Epstein-Barr virus, Kaposi sarcoma-associated herpesvirus).

Clinical Manifestations

Most primary infections in children are asymptomatic; in adolescents and young adults, primary infection often leads to infectious mononucleosis.
Most common symptoms include headache, fever, malaise, fatigue, and sore throat after an incubation period of 30–50 days.
EBV, specifically, is linked with malignancies, showing its genome in Reed-Sternberg cells indicative of classic Hodgkin disease.

Reactivation and Immune Response

Reactivation of latent infections can be silent but may result in increased virus levels in saliva and blood.
EBV-associated conditions are more likely in immunocompromised patients, leading to severe lymphoproliferative diseases.

Diagnosis and Treatment

Diagnosis of EBV primarily involves serologic tests, highlighting the presence of IgM antibodies as indicators of current infection.
Acyclovir can reduce EBV shedding but has no significant effect on symptoms of mononucleosis or lymphoma treatment.
Adoptive transfer of EBV-reactive T cells shows potential as a treatment for EBV-related diseases.

Cytomegalovirus (CMV)

CMV is the leading cause of congenital infections and can lead to severe clinical complications.
Commonly leads to cytomegalic inclusion disease, presenting as enlarged cells in infected individuals, particularly affecting those who are immunosuppressed.

Conclusion

Herpesviruses exhibit complex pathogenic roles, varying host interactions, and significant clinical implications, necessitating ongoing research and treatment advancements for affected individuals.

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Description

This quiz covers key concepts related to the herpesvirus family, which includes significant human viral pathogens. Learn about their structure, size, and the spectrum of diseases they cause in humans. Test your understanding of herpesvirus characteristics and classifications.