Dr. Marwa A. Meheissen: Parvoviruses & Adenoviruses ILOs Quiz

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Questions and Answers

What are the symptoms during the first phase of illness?

Fever, malaise, myalgia, chills, itching (correct)

Headache and dizziness

Nausea and vomiting

Chest pain and shortness of breath

When does viremia occur after infection with the virus?

1 week after infection (correct)

3 weeks after infection

1-2 days after infection

2 weeks after infection

What is the characteristic appearance of the rash associated with erythema infectiosum?

Bullseye pattern

"Butterfly" distribution on face

Spotty appearance

"Slapped cheek" facial rash and lace-like rash on limbs or trunk (correct)

Which body parts are most frequently affected by joint symptoms in adults with this illness?

Hands and knees (B) Signup and view all the answers

When do patients with fifth disease likely become non-infectious?

When the rash fades after 2-4 days (D) Signup and view all the answers

When do specific IgG antibodies typically appear post-infection?

15 days post-infection (A) Signup and view all the answers

What is the fetal loss rate in primary maternal infections of human parvovirus?

Less than 10% (A) Signup and view all the answers

When does fetal death most commonly occur during pregnancy due to human parvovirus infection?

Before the 20th week (A) Signup and view all the answers

What percentage of respiratory tract samples from young children with respiratory infections show the presence of human bocavirus?

1.5% (B) Signup and view all the answers

Which type of infections are associated with the presence of human bocavirus?

Respiratory and Gastrointestinal (D) Signup and view all the answers

What is the most sensitive test for detecting B19 parvovirus and human bocavirus?

PCR (D) Signup and view all the answers

Where has bocavirus DNA been found in individuals?

Serum, Saliva, Stool samples, Respiratory specimens (C) Signup and view all the answers

Which cellular characteristic is essential for the replication of Parvoviruses?

Dependency on functions supplied by host cells (C) Signup and view all the answers

Which human cell type is a primary target for Parvovirus B19?

Erythroid progenitor cells (B) Signup and view all the answers

What is the main site of virus replication assumed in patients infected with human B19 parvovirus?

Adult marrow (A) Signup and view all the answers

Why do Parvoviruses specifically target dividing cells?

Due to their inability to replicate in non-dividing cells (A) Signup and view all the answers

Which characteristic distinguishes Parvoviruses from other DNA viruses?

Dependence on cellular DNA polymerases (A) Signup and view all the answers

What is the most common clinical manifestation associated with human bocavirus infection in children?

Wheezing and respiratory infections (D) Signup and view all the answers

Which age group is most commonly affected by the respiratory disease caused by adenoviruses?

Infants and children (B) Signup and view all the answers

What percentage of pneumonias in childhood are thought to be caused by adenoviruses?

10-20% (A) Signup and view all the answers

Which syndrome caused by adenoviruses occurs among young military recruits under conditions of fatigue, stress, and crowding?

Respiratory disease syndrome (D) Signup and view all the answers

What characterizes epidemic keratoconjunctivitis, a more serious eye infection caused by adenoviruses?

Highly contagious and occurs mainly in adults (C) Signup and view all the answers

In what setting does pharyngoconjunctival fever caused by adenoviruses tend to occur in outbreaks?

Children’s summer camps (A) Signup and view all the answers

What is the common outcome in cases of mild ocular involvement due to adenovirus infections?

Complete recovery with no lasting sequelae (B) Signup and view all the answers

What is the significance of detecting B19 IgM antibody in serologic assays?

It indicates recent infection (C) Signup and view all the answers

How is chronic parvovirus B19 infection diagnosed in immunodeficient patients?

By the detection of viral DNA (B) Signup and view all the answers

What treatment options are available for human bocavirus infections?

No specific treatment (C) Signup and view all the answers

How can human parvoviruses be prevented from spreading?

By practicing good hygienic practices (D) Signup and view all the answers

What is the role of commercial immunoglobulin preparations in treating persistent B19 infections?

They contain neutralizing antibodies to parvovirus (B) Signup and view all the answers

What characteristics describe adenoviruses?

Icosahedral, naked capsid, and double-stranded DNA viruses (D) Signup and view all the answers

Study Notes

Parvoviruses

Parvoviruses are the smallest DNA viruses, naked, and icosahedral with a single-stranded DNA genome.
They have a limited coding capacity, so they depend on functions supplied by replicating host cells.
Viral DNA replication occurs in the nucleus and requires one or more cellular DNA polymerases.
Parvoviruses cannot stimulate resting cells to initiate DNA synthesis, so they must infect dividing cells.

Infections Caused by Parvoviruses

Parvovirus B19 is pathogenic for humans and has a tropism for erythroid progenitor cells.
Human bocavirus is believed to cause wheezing and respiratory infections in children.
B19 virus is widespread and can cause infections throughout the year in all age groups, as outbreaks or sporadic cases.

Pathogenesis of Parvovirus Infections

Immature cells in the erythroid lineage are the principal targets for human B19 parvovirus.
The major sites of virus replication are the adult marrow, some blood cells, and the fetal liver.
The incubation period is usually 1–2 weeks but may extend to 3 weeks.
Viremia occurs 1 week after infection and persists for about 5 days.
The first phase of illness occurs at the end of the first week, with symptoms like flu, fever, malaise, myalgia, chills, and itching.
The first episode of illness coincides with viremia and reticulocytopenia and detection of circulating IgM–parvovirus immune complexes.
A second phase of illness begins after an incubation period of about 2 weeks, with an erythematous facial rash (“slapped cheek” appearance) and a lace-like rash on the limbs or trunk.

Immunity and Diagnosis

Specific IgG antibodies appear about 15 days post-infection.
Detection of B19 IgM antibody indicates recent infection, which is present for 2–3 months after infection.
B19 IgG antibody persists for years.
Antibody may not be found in immunodeficient patients with chronic B19 infections.
In those patients, chronic infection is diagnosed by detecting viral DNA.
Antigen detection assays can identify B19 virus in clinical samples.

Treatment and Prevention

There is no antiviral drug therapy.
Fifth disease and transient aplastic crisis are treated symptomatically.
Severe anemia may require transfusion therapy.
Commercial immunoglobulin preparations contain neutralizing antibodies to human parvovirus.
Good hygienic practices, such as hand washing and not sharing drinks, can help prevent the spread of B19.
Contact precautions and extensive patient room cleaning may help prevent transmission of B19 from patients with aplastic crisis and from immunodeficient patients with chronic B19 infection.

Adenoviruses

Adenoviruses are naked, icosahedral, and double-stranded DNA viruses.
The overall risk of human parvovirus infection during pregnancy is low, with fetal loss occurring in fewer than 10% of primary maternal infections.
Fetal death occurs most commonly before the 20th week of pregnancy.

Human Bocavirus Respiratory and Gastrointestinal Infections

Human bocavirus has been detected in 1.5–11.3% of respiratory tract samples from young children with respiratory infections.
It is prevalent among children with acute wheezing.
The virus has been detected in about 3% of stool samples from children with acute gastroenteritis.
Coinfection rates with other enteric pathogens are also high, so any causative role of bocavirus in gastroenteritis remains uncertain.

Diagnosis of Adenovirus Infections

Detection of nucleic acid is the most sensitive test, with PCR being the most sensitive assay.
Adenovirus DNA has been detected in serum, blood cells, tissue samples, and respiratory secretions.

Clinical Manifestations of Adenovirus Infections

About one-third of the known human serotypes are commonly associated with human illness.
Adenoviruses 1–7 are the most common types worldwide and account for most instances of adenovirus-associated illness.
Adenoviruses are responsible for about 5% of acute respiratory disease in young children, but they account for much less in adults.
Typical symptoms of adenovirus infections include cough, nasal congestion, fever, and sore throat.
Adenoviruses are thought to be responsible for about 10–20% of pneumonias in childhood.
Adenoviruses are the cause of an acute respiratory disease syndrome among military recruits.

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Description

Test your knowledge on Parvoviruses and Adenoviruses with this quiz based on the lecture by Dr. Marwa A. Meheissen. Explore general characteristics, infections, laboratory results, and pathogenesis of these viruses.